detailed project report for phase ii of strategic...

DETAILED PROJECT REPORT FOR PHASE II OF STRATEGIC STORAGE PROGRAMME FOR

CRUDE OIL

MARCH 2013

Volume II PADUR,KARNATAKA

DETAILED PROJECT REPORT

FOR PHASE II STRATEGIC STORAGE PROGRAMME FOR CRUDE OIL

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Template No. 5-0000-0001-T2 Rev. 1

Copyright EIL – All rights reserved

Volume II PADUR

DETAILED PROJECT REPORT FOR

PHASE II STRATEGIC STORAGE PROGRAMFOR CRUDE OIL



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Table of Contents

1 INTRODUCTION ................................................................................................ 5

2 BASIC DESIGN FOR ROCK CAVERN ........................................................... 10

3 PROCESS DESIGN ......................................................................................... 89

4 INTEGRATION WITH EXISTING FACILITIES ................................................ 98

5 FIRE PROTECTION FACILITIES .................................................................. 101

6 INSTRUMENTATION AND CONTROL SYSTEMS ....................................... 106

7 ELECTRICAL INSTALLATION ..................................................................... 119

8 CONSTRUCTION METHODOLOGY ............................................................. 123

9 PROJECT EXECUTION, PLANNING AND CONSTRUCTION SCHEDULE 132

10 OPERATION AND MAINTENANCE ............................................................ 138

11 STATUTARY APPROVALS, CODES AND STANDARDS ......................... 141

12 SCHEME FOR EIA AND RRA ..................................................................... 144

13 COST ESTIMATE ......................................................................................... 153

14 RISK ANALYSIS .......................................................................................... 161

15 RECOMMENDATIONS ................................................................................ 165



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List of Drawings

Basic Design for Underground Rock Caverns

1 A197-001-67-41-1001 Project Layout

2 A197-001-67-41-1002 Cavern Layout Plan

3 A197-001-67-41-1003 Sections of Crude Oil Storage

4 A197-001-67-41-1004 Typical Cavern C/S, Concrete floor & Rock Support

5 A197-001-67-41-1005 Access Tunnel: General Arrangement & Support Detail

6 A197-001-67-41-1006 Water Curtain Layout & Details

7 A197-001-67-41-1007 Shaft Plan, Section & Support Details

8 A197-001-67-41-1008 Concrete Barrier & Separation Wall

9 A197-001-67-41-1009 Shaft Barrier & Casing

10 A197-001-67-41-2010 Geological Map

11 A197-001-67-41-2011 Interpretative Map from NRSC

12 EIL/LF & LU/01 Land Form & Land Use Map

Basic Design for Process Facilities

1 A197-04-41-001-0101 Process Flow Diagram : U/G Rock Caverns

2 A197-04-41-001-0102

Process Flow Diagram : U/G Rock Caverns

Pipeline Integration Scheme

1 A197-000-11-42-3008 Integration Pipeline Route Map

2 A197-000-11-42-3004 Schematic Arrangement for Integration Pipeline

Overall Plot Plan

1 A197-000-1647-0003 Overall Plot plan



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Enclosures

1 Location Map of Storage Site

2 Integration Pipeline Scheme

3 Project Execution Schedule

4 Cost Summary Sheet for Storage Facilities

5 Cost Summary Sheet for Underground Facilities

6 Cost Summary Sheet for Aboveground Facilities

7 Cost Summary Sheet for Integration Pipeline

Annexure

1 Geotechnical Investigation Reports (From Phase-I)



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1 INTRODUCTION

1.0 GENERAL

The present volume outlines the detailed feasibility studies undertaken for the proposed underground rock cavern storage facilities near Padur, Karnataka. Padur, a village belonging to Udupi district, is located on the west coast in south western part of Karnataka state. The proposed site is about 5 km east of Kaup, which is located on the NH-17 connecting Mangalore and Goa at 12 km south of Udupi. It is about 1000 km south of Mumbai by rail extending along the coast of Arabian Sea. The nearest seaport is at Mangalore (New Mangalore Port Trust). The domestic Airport is located at Bajpe, which is 45 km from project site connecting it to Mumbai and Bangalore. Under Phase –I of the strategic storage program, the crude oil storage project of 2.5 MMT is under implementation in Padur. The facility involves development of underground unlined rock caverns for storage of crude oil and laying of a dedicated pipeline connecting the facility to the refinery at Mangalore, located at a distance of about 60kms. Subsequently, the pipeline is connected to the oil terminal (jetty) at the New Mangalore Port. The proposed storage site under Phase-II is located to the south east of the existing storage project, which is under construction (Refer Figure 1.1). With the possibility of having the combined storage facilities, a captive offshore oil terminal (SPM) could be located off the coast of Kaup, which is located at about 5.0 Kms. from the proposed site. This would require the additional pipeline requirement connecting the storage facility to the new offshore oil terminal (SPM) (Refer Figure 1.2). During the prefeasibility study carried out in 2010, an additional storage capacity of 5.0 MMT was proposed at Padur for Phase-II storage program. Further, being located on the western coast of India and on the transshipment route of crude oil from oil exporting countries of Middle East to the oil consuming countries of Far East, the site was envisaged to be developed as an export hub.

However, due to the severe agitation at site, it was not possible to carry out any topography surveys and geotechnical investigations during the present DPR stage. A satellite imagery study was carried out to locate the facility with minimum impact on the local population. This resulted in a reduced storage capacity of 2.5 MMT at Padur. The satellite study was also used to generate topographic data and the geological inputs required for the DPR, which were



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further correlated to the geological data obtained during excavation of the nearby Phase-I storage site.

1.1 SALIENT FEATURES OF STORAGE FACILITIES

With the availability of favorable geological setting, competent rock type and suitable groundwater condition underground unlined rock cavern storage is the selected storage alternative with a total storage capacity of 2.5 MMT. The storage facility is designed to contain two different products, storage A for crude oil with high sulphur content and storage B for crude oil with low sulphur content. Storage A will comprise of three U – shaped caverns where as the Storage B will comprise one U – shaped cavern. Storage A will have approx. 1.875 MMT high sulphur crude oil and Storage B will have approx. 0.625 MMT of low sulphur crude oil i.e. with a proportion of approximately 3:1. The storage facility will have 8 (eight) parallel galleries ( 6 for Storage A and 2 for Storage B) and would involve construction of caverns at a depth of 35 m below mean sea level within the competent rock mass. The hydro geologic containment of the crude oil being stored within the caverns will be ensured through a water curtain systems built above the cavern. Each storage unit is planned to have one inlet shaft and one pump shaft with submersible pump facilities for crude oil filling and evacuation along with other process requirements for a maximum flow rate of 10,000 m3 / hr. With an execution philosophy involving two contract packages of Item rate construction contract for underground cavern storage facilities, one LSTK contract for above ground process facilities and one LSTK contract for pipeline integration facilities, the project is envisaged to be completed in a period of 66 months, which includes 15 month duration for pre bid engineering, tendering and award; followed by 48 months of construction of the facilities and 3 months for commissioning. The detail engineering for the underground works including site supervision, geological mapping of the underground excavation activities and the design of critical items related to containment of stored products will be provided by the Owner / PMC. Based on the basic design performed for the underground storage and associated above ground process facilities, the capital cost estimate has been worked out to be Rs 2226.36 Crores, with an additional approximately cost estimate of Rs. 895.55 Crores for the pipeline integration purpose.



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1.2 PRESENT VOLUME

The volume is presented with following broad chapterization: The chapter on Basic Design for the Underground Storage Facilities outlines the investigation campaign undertaken for the purpose of study, interpretation and analysis of the results and performance of design for the underground storage facilities including cavern dimensions and configuration, required rock supports, water curtain systems etc. The chapter on Process Design for Above Ground Facilities includes the Above Ground Plot plan and Process design and description of the associated process facilities such as submersible pumps, seepage water pumps, on line booster pumps, nitrogen plants etc. The Pipeline Integration scheme has been presented in a separate chapter where in the connectivity of the storage facilities to the proposed new SPM located off Kaup is described. The chapter on Execution Philosophy, Planning and Construction Schedule outlines a broad split of contract packages identified for execution, followed by a planning and construction schedule for the facilities. The Scheme for EIA and RRA has been outlined for the activities to be performed by others so as to confirm the Statutory Approval requirements. Based on the basic design performed for the underground storage and associated above ground process facilities, the capital cost estimate has been presented in the Chapter on Cost Estimates. In consideration of the future commercial operation philosophy, the Operation cost estimate is presented under two components namely fixed cost for the establishment and variable cost for a single turn around operation involving crude filling and evacuation. The last chapter presents the Recommendations and way forward for the purpose of creation of the storage facility at Padur.



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Figure 1.1 : Selected Location for creation of Crude Oil Storage Facilities

with the insert showing Location of the storage facilities at Padur



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Location of Storage site Phase I Phase Ii

Figure 1.2: Location of Storage facilities at Padur, Karnataka along with Pipeline Integration Scheme connecting to new SPM off Kaup, Coast of Karnataka.



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2 BASIC DESIGN FOR ROCK CAVERN

2.0 INTRODUCTION

The purpose of this section is to describe the underground storage facilities design basis including the basic storage principle, overall layout, input from the available site investigations, geological, hydro geological and geotechnical site condition and rock support design and construction philosophy. The proposed site is located near the existing underground storage facilities being built under the phase I storage program and is shown in drawing no. A197-000-67-41-1001.

2.1 OVERALL DESIGN

2.1.1 Storage Principle

The storage facility at Padur will be based on the principle of underground storage in unlined rock caverns with containment of crude oil by groundwater pressure. The storage of crude oil in unlined rock caverns is based on the following basic principles: • The stored crude oil is lighter than water and not miscible in water • The storage cavern is located adequately below the surrounding ground

water level. • Due to natural fissures in the rock mass, water continuously percolates

towards the cavern, thus preventing oil and vapour from leaking out. • Water leaking into the cavern (“seepage water”) is drained to a pump pit

located in the deeper end of the Storage Units, and pumped out from the storage on a regular basis.

2.1.2 Separation of Storage Units

The storage is designed to contain two different products, storage A for crude oil with high sulphur content and storage B for crude oil with low sulphur content. Storage A will comprise of three U – shaped caverns where as the Storage B will comprise one U – shaped cavern. During operation, each unit will have its own product loading and unloading history. Therefore the operating pressure in the units could be different in time and this variation is not necessarily synchronous. Further during operation the vapour pressure in the various cavern units shall be balanced using connections between the cavern units.



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All units are separated by about 100m of rock or with a water filled access tunnel in between. General arrangement, Longitudinal section of the cavern with support details etc are shown in the drawing A197-000-67-41-1001, A197-000-67-41-1002, A197-000-67-41-1003 & A197-000-67-41-1004. Further to ensure hydraulic confinement by continuous flow of water and ensure that water flow is always directed towards the caverns, a horizontal water curtain system is provided. The horizontal water curtain will extend at least 20 meters over and beyond all extensions of storage galleries.

2.1.3 Pressurized Storage

The storage is designed to operate at following vapour pressure conditions:

a) Opening of pressure relief valve 1.5 bar(g) b) Maximum normal vapour pressure 1.3 bar(g) c) Minimum normal vapour pressure 0.1 bar(g) A pressure above atmospheric pressure is always maintained in the cavern, to eliminate leakage of air into the cavern. The cavern shall resist vacuum pressure and is also designed for, as accidental load case, an internal transient explosion of 1 MPa (10barg).

2.2 UNDERGROUND STORAGE FACILITIES.

2.2.1 General

The underground storage facilities consists of Storage A for storage of approx. 1.875 MMT high sulphur crude oil and Storage B for storage of approx. 0.625 MMT of low sulphur crude oil i.e. with a proportion of approximately 3:1. Each U-shaped cavern, with an approximate “D” shaped cross section, is designed to have a shaft with pump installations and pump pit, located at the end of one leg of the cavern, a separate intake shaft is provided at the end of the other leg. Each leg of the U-shaped cavern is 780m long. The caverns are designed to have a span of 20 m, with each leg having a separation distance of 30m between them.

The cavern roof is horizontal along the full length of the cavern. The invert of the cavern units will be having slope from the intake shaft towards the pump pit to ensure free flow of crude and to facilitate dewaxing /desludging operations.



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For construction purposes cross tunnels are provided between the caverns. To ensure circulation of crude oil such cross tunnels will have separation walls.

2.2.2 Location and Orientation

While no specific site investigation campaign could be performed, the underground crude oil storage facilities has been located in a WSW/ENE approximately (N70°E with respect to Plant North) direction, based on the available & collated data from the Phase I storage program. The orientation and location of the caverns is controlled by four predominant joint sets anticipated at the site.

2.2.3 Storage Volumes

The working storage volumes shall result from volume calculation with an assumption of product density of 840 kg/m3 for the high sulphur crude and 880 kg/m3 for the low sulphur crude. Further additional volume considered under the study are as under :

• Presence of a minimum gaseous phase volume : 3% additional volume • Allowing for a minimum of 3 days of storage of seepage water for an unlikely

event of failure of seepage water pumps.

The corresponding excavation volume is briefly summed up as under:

• Vertical shafts and sumps : 26000 m3 approx. • Access tunnel to storage caverns : 290000 m3 approx • Water curtain galleries : 165000 m3 approx • Storage units : 3250000 m3 approx

The excavated volume for storage units has been increased by 120000 m3 to account for the volume of the concrete floor (i.e. backfill & concrete slab). The above quantity do not take into account temporary excavations as turning shelters, niches are to be excavated according to detail design & construction requirements. Total approximate volume of excavation is in the range of 3750000 m3 of in place rock. The excavated material has been planned to be disposed partially on the top of the U/G facilities i.e. OWNER’s plot and partially transported to a remote storage. The corresponding volume is estimated to be in the range of 5000000 m3 (swelling factor 1.4)



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2.2.4 Access Tunnels

For construction purposes, two independent access tunnels are planned from the surface to allow for use of heavy equipment for excavation of the rock caverns and execution of underground civil and installation works. The accesses have been designed with the objective of time schedule as well as safety during the excavation phase and for engagement of two mutually exclusive U/G excavation agencies. All portals are selected ensuring easy and exclusive access, so as to have independent access to the dumping areas for muck disposal. Both northern and southern portal take advantage of topography in order to obtain quickly sound rock cover for the access tunnel. In addition, for safety reason, curves for the access tunnel have been minimized. The access tunnels are designed with a slope of 1:8 and are horizontal in curved segments. The main access tunnels are designed to allow two-way traffic with heavy dump trucks. Parts of the access tunnels & cross tunnels will be used for both access and storage. A Typical General Arrangement of access tunnel is shown in the drawing A197-000-67-41-1005.

2.2.5 Storage Units

The storage facility consists of 8 parallel galleries (6 for Storage A and 2 for Storage B). The cavern geometry is made of 570 m2 cavern section (maximum section), 780 m length and 30 m pillar width. The cavern roof elevation is -35 m MSL and the cavern floor elevation varies between -55 m to -65 m MSL. All the eight U – shaped cavern units are designed to have same main cross section ranging from 30 m x 20 m (H x w) at the outlet end where it is connected to the pump shaft to 20 m x 20 m (H x W ) at the inlet shaft connection. The cavern cross section is designed to achieve a favourable stress situation in the rock. A Typical Cross section of cavern with support arrangement is shown in the drawing A197-000-67-41-1004. The caverns in the Storage Units are designed for excavation with top-headings and benches. The top-heading is designed with 8 meters in height. As the height of the cavern varies due to the inclination of the floor, the height of the benches will vary. The partition in height of each bench shall be defined during the Detailed Design phase.



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Storage galleries are connected at the upper and lower levels by connecting galleries. Additional connecting galleries may be provided within a storage unit to aid construction. All connecting galleries between the two legs of a cavern unit shall be equipped with concrete separation walls in order to avoid the product by passing the foreseen circulation. All connecting galleries from the cavern unit to access tunnels shall be equipped with concrete barriers to ensure tightness.

2.2.6 Water Curtain System

The objective of the water curtain system is to recharge the permeable joints and allow continuous water flow from the rock mass towards the cavern. Therefore, the water curtain system (the water curtain boreholes) is designed to intersect the most pervious joints or the most pervious joint set. Considering the geological setting characterized by the pre-dominant joint sets, the water curtain gallery is oriented N700E (approximately) i.e. parallel to alignment of cavern. The water curtain boreholes shall be of about 50-75m length, inclined 100 downwards, with a initial spacing of 20m and oriented at an angle of about 70-900 with respect to the axis of the water curtain gallery. However based on the geological mapping of the water curtain gallery the appropriate orientation, spacing and length of the boreholes shall be decided during the detailed engineering and construction stage. A Typical General Arrangement of water curtain tunnel is shown in the drawing A197-000-67-41-1006. The access to the water curtain gallery is made from the access tunnels. Length of WCG boreholes has been limited to 75 m and diameter of holes is minimum 95 mm. Water curtain boreholes will be drilled approximately 1 m above the water gallery invert. The horizontal water curtain shall be constructed 20 m above the cavern roof (elevation is -13.8 MSL approx. for borehole and -15 MSL for water gallery invert).

The final spacing and orientation of boreholes will be assessed on site subsequent to specific water curtain testing during construction stage. In order to supply the water curtain boreholes during the construction period, a temporary water supply line will be installed in each branch of the water curtain gallery. In order to take into account a possible shortage of the water supply, it is necessary to have a surface water storage. The volume of this capacity shall correspond to a minimum period of 5 days of water supply.



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It is necessary to maintain pressure in the water curtain system during all phases of the construction period, before excavation of the storage cavern for the following reasons: • The fissures in the rock shall be pressurized and water filled and never

drained. It is nearly impossible to re-fill fissures that have once been drained.

• During drilling and blasting of the gallery of the storage cavern, water leaking zones between water curtain and storage cavern are identified and if necessary pre-grouting are to be performed during excavation of the gallery. Pre-grouting being far more efficient than post grouting, will be performed to ensure reduction in water leakage.

During the construction phase the water curtain acts by maintaining the ground water level in the vicinity of the excavated caverns, thus reducing influence on the surrounding ground water. During the construction period, the boreholes will be connected to the main injection line along the water curtain gallery. Prior to tightness testing of the caverns, the temporary water supply system to the water curtain bore holes shall be disconnected and water curtain tunnel shall be flooded with. This activity shall be carried out in stages.

A permanent water supply of the water curtain will be necessary.

2.2.7 Shaft

One operation shaft and one inlet shaft is designed for each U –shaped cavern. Shaft layouts are to be finalized during the construction stage. A Typical General Arrangement of shaft with support arrangement is shown in the drawing A197-000-67-41-1007.

2.2.8 Cavern floors

To facilitate the flow of crude as well as the desludging/de-watering sequences during operation, the cavern invert is levelled and covered by concrete, sloping longitudinally 1:250 towards the pump pit. Laterally, the cavern floor slopes 1:12 from the centre line towards the side walls to create favourable flow velocity for rinsing of sediments. A Typical General Arrangement of cavern floor is shown in the drawing A197-000-67-41-1004.



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2.2.9 Concrete Barriers and Walls Concrete barriers shall be provided to isolate the product from the external environment in tunnels and shafts and to separate units. Concrete separation walls shall be provided for circulation of crude oil, vapour and inert gas. A Typical General Arrangement of concrete barrier and wall is shown in the drawing A197-000-67-41-1008.

2.2.10 Casing and Pipes in Shaft

For the purpose of installation of pumps and instrumentations in the shafts, casings will be installed in the shafts. In addition there will be process piping in the shafts and caverns. The shafts will be backfilled with mass concrete where in these casings and pipes will be embedded above the concrete barriers. A support framework will be provided on top of pump pit. Additional structural support to casings/pipes shall also be provided between the pumpit and the concrete barrier. A Typical General Arrangement of casing and pipes in shaft is shown in the drawing A197-000-67-41-1009.

2.2.11 Monitoring Wells

Monitoring wells shall be installed to monitor the hydro-geological conditions and water quality during both construction and operation. These wells shall be completed before start of excavation works.



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2.3 SITE ASSESMENT AND INVESTIGATION

2.3.1 Introduction

Site-specific geotechnical investigation campaign could not be under taken due to the severe agitation by the local residents. The interpretative geological, hydro-geological and geotechnical model is prepared based on the available topographical, geological and geotechnical information collated from the excavation-mapping data from the underground facilities being built under the phase I storage program. The topological and geological maps have been derived from the satellite imageries and field verification. Three site investigation campaigns were carried out at the Padur site under Phase 1 storage program. The initial site investigation was carried out during DFR stage in 2005, the second, supplementary site investigations were carried out during the basic engineering design stage in 2009 and the third, mandatory site investigations were carried out before the actual construction of project in 2010.

2.3.1 Initial Site Investigations, 2005

The following investigations were carried out during the initial site investigations:

• Geological mapping and assesment • Geophysical Investigation (Seismic refraction & Electrical resistivity) • Core drilling – six numbers (vertical and inclined) • Laboratory testing of core and water samples • In situ stress measurement • Hydro-geological test (Water pressure tests and water level monitoring) The purpose of the Initial Site Investigation, which covered a large area, was to acquire geotechnical data for assessing the feasibility of the proposed location. The results of the investigation are outlined hereunder.

(a) Geological Mapping and assessment

Based on a reconnaissance survey, the site was selected for the purpose of geological mapping and assessment. The mapping covered delineations of litho units, different geological features such discontinuities, joints, major structures etc. The results from the geological mapping are presented in detail under section 2.4.



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(b) Geophysical Survey

Six lines of various lengths (a total of 2590m) were surveyed by the seismic refraction method using 24-channel array at 5m interval. Similarly, five lines of various lengths (a total of 4950m) were surveyed by the electrical resistivity method. The electrical resistivity imaging was done by using dipole array with an electrode spacing of 10m by using a 72-electrode imaging system. Location of seismic refraction survey lines and resistivity mage profile is shown in Figure 2.1. The locus of shear zones of lines E1,S3 and E2 form a 200-250m long North-South trending shear plane and is shown by site area centre. Similarly locus of shear zones are reflected on lines S4,S5 and S6 from a 500m long shear plane tending East-West. Both these shear zone are seen between RL = -10m to -24m. A fine-grained sand and clay layer struck between 23-26m in the nearby borehole (PB-5) furthere confirms the presence of the shear Zone Overall feature reveals from seimic section that good quality bedrock is almost continuous below RL=-20m except at these shear zones where they are deeper by at least 5m.

Figure 2.1 Schematic site plan showing geophysical survey lines



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(c) Core Drilling

The core drilling program is presented in Table 2.1, showing coordinate, bearing, inclination and length of each core hole. The total drilled length is close to 630.07 m. All holes are drilled down to a level that is equal to/deeper than proposed cavern floor.

Table 2.1 Core Drilling

Following observations are made based on Borehole data

1. The RQD values of Borehole PB 5 showing low value as it is falling in the lineament zone in the valley south of the proposed plot.

2. All the other core holes show RQD and core recovery above 90 % in cavern area

3. It is further noted that only PB 6 is near to the proposed location. Refer Annexure for Report on Geotechnical Investigation for the detailed core logging.

(d) Laboratory Testing

Table 2.2 shows the mean values and standard deviation derived from the laboratory investigation

Borehole Coordinates

Azimuth Inclination Length

(m) NX

76mm Northing Easting Z (MSL)

PB-1 1461212.266 475728.882 -1.673 Vertical 91.7

PB-2 1462022.315 476955.483 +12.073 N270E 30/Ver. 123.0

PB-3 1462392.307 475904.617 +4.079 N180E 30/Ver. 107.03

PB-4 1462065.625 476485.560 +8.889 Vertical 103.50

PB-5 1461547.506 476702.897 -0.361 N360E 30/Ver. 95.81

PB-6 1460934.177 477497.711 +17.205 Vertical 109.03



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Table 2.2 Intact Rock Properties

Parameter Mean

Value

Standard

Deviation Remarks

Bulk Density (KN/m3) 2.71 ±0.12

Porosity 0.4% ±0.2

Sonic Velocity 4994 ±600

UCS (MPa) 133.66 ±42.58

Tensile Strength (MPa) 6.70 ±2.38

Poisson’s ratio 0.23 ±0.09

Cohesion (MPa) 18.02 ±7.43 Tri axial test

Friction angle 56.44 ±7.60 Tri axial test

The test results show wide variation in the parameters, which could be attributed to the large range area of investigation and the geological features, which have been investigated. The detail results are presented under Report on Geotechnical Investigation at Annexure.

(e) In-situ Stress measurement

Seven hydro fracturing tests were carried out in PB1. However, the orientation data could not be obtained, as the toll got stuck. Subsequently, eight nos. of hydro fracturing tests were run in PB 6 with the standard procedure and impressions. The interpretation took into account hydro fracturing data from PB 1 (without orientation) and hydro fracturing values as well as orientation in PB 6.

Table 2.3 presents the depths of tests in the two boreholes. The range of depth is wide enough to ensure a good quality of the estimation of the horizontal stress components and avoid hazardous correlations.

The detailed analysis of the data indicates the following results for the virgin stress field (unit in MPa): Sh=0.075 + 0.0575 . z SH = 0.475 + 0.1025 . z SV = 0.026 . z



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With Sh the minor horizontal stress, SH the major horizontal stress and SV the vertical stress and z the depth in meter below ground level. The mean orientation of the induced fractures in borehole PB 6 suggests a direction of N156E (±14 deg) for SH. The horizontal to vertical stress ratio is about 2 for the minor horizontal stress (Sh/SV) and about 4 for the major horizontal stress (SH/SV) at the depth of the storage.

Table 2.3 Insitu-stress Measurement

(f) Hydro-geological Investigations

Results of water pressure test, analysis thereof are discussed in the section under Hydro-geology Section 2.5. Results of water level monitoring and its analysis are discussed in the section under Hydro-geology Section 2.5.

Borehole Test # Depth (below ground level)

Major horizontal principal stress SH

PB-1 1 87 m 7.5 PB-1 2 81 m 6.3 PB-1 3 75 m 5.3 PB-1 4 68 m 5.9 PB-1 5 65.2 m 6.8 PB-1 6 58.7 m 5.7 PB-1 7 58.3 m - PB-6 1 92 m - PB-6 2 85 m 9.1 PB-6 3 73 m 7.9 PB-6 4 65 m 7.6 PB-6 5 55 m 5.9 PB-6 6 50 m 5.5 PB-6 7 45 m 3.5 PB-6 8 35 m 3.7



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2.3.2 Supplementary Site Investigations, 2009

The Supplementary Site Investigation took place at the time of Basic Engineering stage in 2009. The following investigations have been performed: Geological Mapping Geophysical Investiation (Seismic refraction & Electrical resistivity) Core drilling – Six numbers ( vertical and inclined) Laboratory testing of rock and water samples Hydro-geological test (Water pressure tests & water level monitoring)

(a) Geological Mapping

The results from the geological mapping are summarized and presented in detail under section 2.4.

(b) Geophysical Investigation Seismic refraction studies have been carried out at 9 nos. of seismic refraction profiles covering total length of 2310 almost in grid pattern for better appreciation of bedrock. Based on the investigation summary of the seismic velocities and inferred lithoogy are summarized in the table 2.4.

Table 2.4 Inferred Lithology from Seismic Refraction Studies

Layer Seismic velocity(m/sec)

Inferred Lithology

Topmost layer 565-1135 Lateritic soil/ silty soil Thin zone with varying thickness along profiles

Second layer 2057-2413 Weathered Granite/Granitic gneiss Lower velocity indicates higher degree of weathering, whereas high velocity indicates lower degree of weathering along with fracture and joint in the rock mass

Third layer 3700-4500 Granitic gneiss Massive nature of rock mass with meager fracture<3500m/sec: higher degree of fracture/joint

Fourth layer 5184-6920 Massive Granite/Granitic gneiss



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Based on the compressional wave velocity (Vp), Q value and rock mass

category has been estimated with the empirical relation .

The rock mass category in the area of investigation generally varies from fair to extremely good conditions. However, very poor rock mass condition has been estimated with seismic velocity less than 3500m/sec. 10 nos. of resistivity profiles have also been carried out with a total coverage of 2427.5m.It can be concluded from 2 D resistivity imaging survey that at places very low resistivity zones have been identified below high resistivity zones. These low resistivity zones may possibly be indicating highly jointed or fracture rock mass of Granite/Gneissose Granite under saturated condition. 2 D resistivity image survey reveals in general four distinct layers having different resistivity contours with varying thickness as shown in the table 2.5.

Table 2.5 Inferred Lithology from 2 D Resistivity Studies

Resistivity Value Inferred litho logy

166 Ω-500 Ω Highly jointed or fracture rock mass of Granite/Gneissose

Granite (under saturation) 500 Ω-1000 Ω Moderately jointed or fracture rock mass of

Granite/Gneissose Granite (unsaturated condition) 1000 Ω-2000 Ω Less jointed or fracture Granite/Gneissose Granite

(unsaturated condition) 2000 Ω-15000 Ω Hard and massive rock mass of Granite/Gneissose

Granite

The detail results are presented under Report on Geotechnical Investigation at Annexure. (c) Core Drilling The investigation comprises four vertically drilled boreholes (SPBH1, SPBH2, SPBH4 and SPBH6) with drilled depths between 101.5m and 120m and SPBH3 and SPBH5 are inclined bore holes with inclination angles of 30 degrees and with vertical depths of 151.02m and 40.703m, respectively. The diameters of the holes were NX size (76 mm) and were drilled using rotary drilling equipment. The core-drilling program is presented in Table 2.6.The total drill length is close to 674.1. Bore hole SPBH-4 is near to the proposed location.



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Table 2.6 Characteristics of cored boreholes (2009)

Reference the drilling observation, it is concluded that the bedrock encountered in the project area is of good to very good and even excellent quality having 100 % core recovery & more than 90-100 % RQD. The joints met in borehole only at shallow depth except SPBH-03 where the joints are more prominent in between 119 to 155m depth. Refer annexure for detail result and analysis of the geological and geotechnical log of the bore hole conducted during this stage. (d) Laboratory Testing The mean value and standard deviation have been derived from the testing as shown in Table 2.7


Parameter Mean Value Standard Deviation Remarks

Bulk Density (KN/m3) 26.8 ± 0.075

Sonic Velocity 5252 504

UCS (MPa) Dry 163.0 ± 27.0

Wet 144.0 ± 34.0

Tensile Strength (MPa) 12.0 ± 2.0

Young’s Modulus (GPa) 62.0 ± 4.0

Poisson’s ratio 0.24 ±0.04

Cohesion (MPa) 38.75 ± 8.41 Tri axial test

Friction angle 49.30 ± 3.01 Tri axial test



(m) Northing Easting Z

(MSL)

SPBH-1 1461828.930 476970.471 20.994 Vertical 120

SPBH-2 1462433.317 477309.674 12.62 Vertical 101.5

SPBH-3 1462265.026 477027.745 9.309 N240°E 30°/Ver. 175.6

SPBH-4 1461863.992 477511.939 34.250 Vertical 120.0

SPBH-5 1462280.187 477253.586 10.573 N240°E 30°/Ver. 47

SPBH-6 1461942.855 477279.132 29.617 Vertical 110.0



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(e) Hydro-geological Investigations

Results of water pressure test and analysis thereof are discussed in the section under Hydro-geology Section 2.5. Results of water level monitoring and its analysis are discussed in the section under Hydro-geology Section 2.5.

2.3.3 Mandatory Site Investigations, 2010

Under Phase-I storage program, the civil works for underground works is divided into two independent contracts with vertical split of work, to be executed by two contractors and are designated as Part A & Part B. Proposed location in Phase-II storage is close to the area near Part B and therefore results and interpretation of the investigation scheme performed in part B are discussed here. The test, which was performed in the area under Phase-I storage program before the actual construction, is as follows:

Geological Mapping

Core drilling – Eight numbers (7 inclined and 1 vertical) in Part-A & Eleven number (6 inclined and 5 vertical) in Part- B

In-Situ Test (SPT)

Laboratory testing of rock and water samples

Hydro-geological test (Water pressure tests and water level monitoring)

(a) Geological Mapping

The results from the geological mapping are presented in detail under section 2.4.

(b) Drilling The characteristics of all boreholes located in the Part B contract area are given in table 2.8.



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Table 2.8 Characteristics of cored boreholes Part B (2010)

The investigation results reveal that the top layer consists of laterite and weathered zone of bedrock. Bedrock is mainly composed of fresh granitic gneiss with fractured contact zones.. (c) In-Situ Test (SPT) SPT test was done for the soil layer at APBH-6, APBH-7, APBH-8, APBH-9 & APBH-10.The values of residual soil are in the range of relative density of medium to dense sand. (d) Laboratory testing The average value from the laboratory tests are summarized in table 2.9.

Table 2.9 Intact Rock Properties Parameter Mean Value Remarks

Bulk Density (KN/m3) Dry 26.2

wet 26.9



(m) Northing Easting Z

(MSL)

APBH-1 1461623.00 477069.00 26.27 N00E 30/vert. 145.0

APBH-2 1461747.00 477158.00 28.70 N20E 30/vert 125.0

APBH-3 1462002.88 477270.78 28.61 N60E 30/vert 121.0

APBH-4 1461888.73 477398.84 34.44 N45E 30/vert 125.0

APBH-5 1462152.12 477502.79 24.23 N70E 30/vert 110.0

APBH-6 1462200.00 477600.00 18.29 N30E 30/vert 105.0

APBH-7 1461923.56 477102.56 38.72 Vertical 23.3

APBH-8 1461906.21 477114.30 40.52 Vertical 27.7

APBH-9 1461888.85 477122.45 40.70 Vertical 31.0

APBH-10 1461812.46 477023.32 22.90 Vertical 94.7

APBH-11 1461625.56 477132.95 31.41 Vertical 101.1



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Water absorption 0.22

UCS (MPa) Dry 132.2

Wet 117.9

Tensile Strength (Mpa) 11.2

Young Modulus (Gpa) Dry 56.9

Wet 53.8

Poisson’s ratio 0.23

Cohesion (Mpa) 26.1 Tri axial test

Friction angle 54.6 Tri axial test

(e) Hydro-geological Investigations

Results of water pressure test and analysis thereof are discussed in the section under Hydro-geology Section 2.5.

Results of water level monitoring and its analysis are discussed in the section under Hydro-geology Section 2.5. 2.3.4 Conclusion All phases of investigations included geological mapping, core drilling, laboratory testing of core and water samples, seismic refraction survey, electrical resistivity survey, water pressure tests, groundwater level monitoring and groundwater analyses. Based on the above investigations, consolidated findings about rock mass behavior, rock mass structure and rock mass condition has been obtained and a basic model with respect to geotechnical, geological and hydro geological conditions created. To develop a geotechnical model, a broad conclusion drawn based on the various investigations is as follows:

(a) Drilling

From the drilling results, soil layers comprising of lateritic soil and residual soil are distributed having thickness of 0.5-6m. Bed rock appeared to have a RQD in the range of 90-100%. Most of the joint met in boreholes only at shallow depth. Borehole no. PB-6 performed during initial site investigation (2005), borehole no. SPBH-4 performed during supplementary site investigation (2009) and borehole



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no. APBH 1, 2, 4 & 10 performed during supplementary site investigation (2010, part B) are close to the proposed location selected for Phase-II storage program. (b) Laboratory Testing The average value of lab tests taken for engineering purpose are given in the table 2.10


Parameter Mean Value Remarks

Bulk Density (KN/m3) 27 High dry density

Porosity 0.45% Very low

Water Absorption 0.2% Low

Sonic Velocity 5252 High to very high

UCS (MPa) Dry 133 Competent crystalline

rock matrix Wet 118

Tensile Strength (MPa) 12 High

Young Modulus

(GPa)

Dry 57

Wet 54

Poisson’s ratio 0.23

Cohesion (MPa) 26

Friction angle 54

Cercher Hardness Index 51

Cercher Abrasivity Index 3.3

(c) In situ Stress Measurement

The mean orientation of the induced fractures in borehole PB-6 suggests a direction of N156E (±14 deg.) for SH. The horizontal to vertical stress ratio is about 2 for the minor horizontal stress (SH/SV) and about 4 for the major horizontal stress (SH/SV) at the depth of the storage.



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2.4 GEOLOGY

2.4.1 Introduction

This section outlines the geological model of the selected site for phase II storage program involving underground unlined rock caverns near Padur. With an objective to locate the storage facilities for an envisaged capacity of 5.0 MMT, reconnaissance survey was undertaken near the existing site where the phase I storage program is being implemented. The phase I storage program involves underground unlined rock caverns for a storage capacity of 2.5 MMT. Based on the recee, a surface geological mapping campaign was undertaken for the identified site. Having established the possibility of locating storage facilities for a total storage of 5.0 MMT, owing to a severe agitation by the local residents, the follow up geotechnical investigation campaign could not be taken up. Therefore, through available remote sensing data, interpretative geological map and very limited ground truth verification the proposed site assessment was undertaken. This lead to identification of a smaller land parcel and the resultant reduced storage capacity of 2.5 MMT. Constrained with unavailability of site-specific geotechnical data, through an interpretative assessment of the various available information, the geological model of the selected site has been developed.

2.4.2 Land Form and Land Use Mapping

Owing to agitation by the local residents, on site geotechnical investigation campaign could not be undertaken. Therefore, based on a joint decision; in order to assess the impact of the proposed project on the local habitation, a land form and land use mapping exercise was under taken. Using the digital remote sensing data and very limited ground truth verification, the morphological features, rock out crops, fertile land parcels and dwelling units within the site were established. This involved procurement of SOI topographical maps, satellite imageries, analysis of the digital data and interpretation of the surface features. The land form and land use map is furnished at Annexure . Based on the interaction with the district administration, in order to have minimum impact on the local populace, it was decided that the segment of land parcel with relatively higher population density index will be excluded. Thus, a reduced land parcel lying south east of the phase I storage facilities have been selected with a considered storage capacity of 2.5 MMT instead of 5.0 MMT.



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Despite the effort, since no site specific investigation could be undertaken, it was decided that all the available topographical and geological information will be collated and studied for development of an interpretative geological model. The inputs include the available investigation results covering the near vicinity area, excavation mapping data from the underground facilities being built under the phase I storage program; the topographic map, the satellite imagery of the selected site, the interpretative geological map derived from the satellite imageries and field verification. While for the purpose of this DPR, the interpretative model is developed it is to be noted that prior to execution of the project, site specific investigation campaign is required to be carried out so as to reaffirm the assumptions and undertake the detail design of the storage facilities. The intent of this section is to compile the results of the investigation campaigns and to develop a geological model of the site.

2.4.3 Geological Investigation

(a) DFR for Phase I Storage Faciltites

Through a pre-feasibility study and reconnaissance survey of the region the proposed location was selected. Thereafter, an area of about 2km. X 2km. was identified for undertaking the investigations during the DFR stage.

For the purpose of geological mapping traverses were made across the entire selected site so as to map the exposures/ out crops, litho-units and large scale structural features and small scale discontinuities including the joint sets associated with the outcrops. The observed details were plotted on the SOI topographic map and later translated on to the detailed topographic maps prepared at a scale of 1: 2000. Having mapped the geological setting of the site, investigation scheme for electrical resistivity and seismic refraction survey were finalised. The entire area was covered through six seismic refraction survey lines totalling about 2.6 km length and six lines of electrical resistivity surveys lines totalling about 5.0 km. Based on the geological mapping 6 core drilling (3 Inclined & 3 vertical) locations were selected so as to have a representative coverage of the entire area (2km. X 2km.). During the core drilling geological logging of the cores were undertaken so as to corroborate the surface geological interpretations. Geophysical (sonic) logging was also carried out in the core-holes. Samples were selected for petrographic analysis through thin section studies.



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(b) Supplementary Investigations for Phase-I Storage facilities

Having carried out the detailed investigations it is observed that the entire site is transected by a structural/topographic lineament broadly dividing the site into two areas the northern part and the southern part. Therefore, based on this geologic revelation and other parameters such as population density, suitable access for cavern construction, muck disposal and topography, the north eastern part of the site was selected for siting of cavern for phase I storage program. In view of this, while the scheme of investigations was well spread for the entire area, the selected location for the caverns is reportedly characterised by only one representative borehole and a few segment of seismic and electric survey lines. Therefore, prior to commencement of the execution of the project a supplementary investigation campaign was carried out. This involved a focused approach for the selected location and collection of geological, geotechnical and hydro-geological data so as to minimise the technical uncertainties. As part of the supplementary investigations, for the purpose of geological model the following activities were carried out. • Engineering geological mapping of the site ( an approx. area of one sq.km.)

for the selected location; • Additional geophysical investigations comprising of seismic refraction surveys

of 2310m line meter and electrical resistivity surveys of 2430m line meter covering the selected location;

• Geological core logging of the additional core-holes within the selected location, which includes four vertical coreholes ( SPBH1, 2, 4 & 6) and two inclined coreholes ( SPBH3 & 5);

• Geophysical logging of the above additional coreholes.

The re-visit during the geological mapping of the site aimed at the following: • Gathering details on the litho-stratigraphy of the selected location; • Gathering structural discontinuities, if any, in the under ground facility area; • Gathering rock parameters for rock mass characterisation in the underground

and above ground facility areas; • Assessing the geological setting of the cavern location; • Establishing suitability of the cavern location vis-a-vis the access for

construction, muck disposal areas etc.



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In addition to the above, the Geological Survey of India (GSI) was engaged for an independent assessment of the geological setting of the proposed site through surface geological mapping and review of the geological logs of the coreholes.

(c) Mandatory Investigation for Phase I Storage Faciltites

Prior to execution, mandatory geotechnical investigations involving core drilling and hydro-geological testing were carried out for the identified portal and shaft locations for the underground facilities. The objective of these campaigns was to have on site information for detail design and rock support requirements for the portals for the access tunnel and the fore shaft & shafts.

2.4.4 Geological Information from Phase I Underground Faciltiies

The underground facilities associated with the caverns are the shafts, access tunnels, water curtain tunnels, water curtain boreholes and the storage caverns. The storage caverns are being excavated in multiple stages viz. heading and benches. As part of the excavation cycle, geological face mapping is being carried out for the underground facilities. Based on the mapping results the rock-mass type is being identified and the corresponding design rock-support is being installed.

For the purpose of water curtain system, while majority boreholes have been drilled through destructive drilling; selected water curtain boreholes have been core-drilled and logged for ascertaining the geological features.

Further, the storage caverns are being excavated with an on–the–go–design approach, where in the predictive geological model is being prepared and updated continuously, with progress of excavation of heading and subsequent benches. Therefore, owing to lack of any site specific data for phase II storage site, compilation of the available geological information from the near by phase I underground facilities forms a key assumption / input for the present studies.

2.4.5 Interpretative Geological Model

As an innovative approach, since no geotechnical investigation could be conducted for the selected land parcel for phase II storage program, it was decided that the interpretative geological model be prepared with the available data from the various sources such as investigation campaigns of DFR, Bid



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Engineering stage, Detailed Engineering stage and the compiled excavation mapping results.

These data were coupled with the topographic survey maps generated through digital remote sensing data and the derived land form and land use maps. Further, the satellite imagery data were used for lineament studies and identification of interpretative geological discontinuities. In continuation to the aforesaid, the interpretative geological map from National Remote Sensing Center was also studied for deriving the geological model with a better degree of assumption.

2.4.6 Geological Model

2.4.6.1 Regional Geological Setting

Gneissic rocks, otherwise known as Peninsular Gneisses, belonging to this region are the most widespread group of rocks in Karnataka and many parts of southern India. These are characterized by heterogeneous mixture of different types of granites intrusive into the schistose rocks after the latter were folded, crumpled. They include granites, granodiorites, gneissic granites and banded or composite gneisses, the granitic constituents of which show distinct signs of intrusion.

The banded gneisses consist of white bands of quartz-feldspar (felsic bands) alternating with dark bands containing hornblende, biotite and minor accessories (mafic bands). The gneissic types are due to the intensive granitisation of older schistose rocks and show streaky and contorted bands of which are granitoids to porphyritic and others granulitic intrusive of different ages, difficult to say but their very complex nature is unquestionable since they include composite gneisses, migmatites, granitised older crystalline rocks and true granites with their aplitic and quartz vein systems. These lithounits represent rocks of different ages i.e. the earlier schists and the latter intrusions of possibly different periods.

The peninsular region of the Indian subcontinent belongs to a stable regional zone since no major tectonic event occurred subsequent to formation of these rocks. This stable zone is referred as Dharwar craton, named after the Dharwar region, and is composed of various types of rocks as described above.



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Within these various rocks forming the craton, gneisses is considered as the "fundamental" basement. Gneisses include gneiss, granitic gneiss or granite. All these facies are collectively known as "Peninsular Gneisses" in the literature.

The gneiss of the western block of the peninsula is older (3.0 to 3.2 Ga) than those of the eastern block (2.7 to 2.9 Ga). (The above is an excerpt from the book Geology of India & Burma by M. S. Krishnan, 3rd Ed, 1956, Assoc. Press, Madras).

2.4.6.2 Seismicity

Mangalore and its vicinity covering padur are classified as Zone III as per Seismic Zone map of India where the seismic coefficient is about 0.04 g. The project structure being seated >30m below the ground level (at any point below the lowest point on ground) this coefficient may be reduced by 0.5 for seismic design.

2.4.7 PROJECT GEOLOGICAL SETTING

2.4.7.1 Geomorphology

The proposed site at Padur, in the Udupi district is located along the National Highway NH17connecting Goa and Mangalore, at 15 km south from Udupi city and 50 km North from Mangalore. The coast line of Arabian sea is about 5 Km from the site. The airport is located at Bajpe (Mangalore) about 45 km south east from the site.

The topography of the area exhibits an undulatory hilly terrain traversed by a narrow central valley oriented roughly east-west. The fringing plateaus on either side have an elevation difference of about 20 m. The plateau and the flanks towards the valley are characterised by a number of gneissic hilly outcrops orientated North–South with an elevation of about 35m to 40m. The central valley and the valley flanking the northern part of the site is characterised by vegetation and paddy fields.

The selected site for phase II storage program is located to the east of the valley and to the south east of the phase I storage site.



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2.4.7.2 Litho-stratigraphy

The gneissic rocks belonging to this area include granites, granodiorites, gneissic granites and banded or composite gneisses, the granitic constituents of which show distinct signs of intrusion. The banded gneisses consist of white bands of quartz-feldspar alternating with dark bands containing hornblende, biotite and minor accessories.

In the study area, peninsular gneiss is by far the most represented rock type. However, granites are also found at some places. Though a few basic dykes were reported for the entire area during the DFR stage, no such surface manifestation is reported indicating presence of basic dyke in the project facility area.

As part of the geophysical investigation, interpretation of the seismic refraction survey data has been carried out with special attention to find out any low velocity zone within the basement rock along the seismic lines. Seismic refraction studies have been carried out at 9 nos. of profiles at proposed area. The seismic refraction survey data has reveals four distinct layers with different seismic velocity contrast with depth. The abstract of seismic velocities are summarizes as under:

Topmost layer comprises of overburden lateritic soil / silty soil, of varying compactness. This top layer is very thin having varyiable thickness along profiles. This layer has seismic velocity of the order of 500 m/sec to 1100 m/sec.

Second layer comprises of weathered Granite / Granite gneiss having seismic velocity of the order of 2000 m/sec to 2400 m/sec, which increases with depth. Lower velocity indicates higher degree of weathering, whereas high velocity indicates lower degree of weathering along with fracture and joint in the rock mass.

Third layer comprises of fresh Granite/ Granite gneiss (lower velocity < 3500 m/sec indicates lesser degree of fracture/ Joint, whereas the higher velocity in the range of 3700 m/sec to 4500 m/sec represents massive nature of rock mass with meager fracture.

Fourth layer comprises of massive Granite / Granites Gneiss having seismic velocity of the order of 5100 m/sec to 6900 m/sec forming basement.



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A reasonable correlations of seismic results have been reported when compared with the available drill hole data. No distinct low velocity media or anomalous features are reported from the study.

In addition to the above, 2D resistivity imaging survey has been carried out along the seismic lines to supplement/compliment the findings inferred from seismic survey and detailed geological mapping. The interpretation of the Resistivity data has been carried out with special attention to find out any low resistivity zones within the basement rock having very high resistivity along the resistivity lines.

As has been reported from the Resistivity images, at some places very low resistivity zones have been identified below high resistivity zones. These low resistivity zones may possibly be indicating highly jointed or fractured rock mass of Granite / Gneissose Granite under saturated condition.

These low resistivity zones are found to be having a reasonable correlation with the geological logging of cores with joint sets. However, having adopted an integrated approach of analyzing the data along with surface geological mapping, no major structural weakness zone is expected at the site. The independent assessment by GSI also confirmed the aforesaid interpretation.

2.4.8 Rock Types

Lateritic soil/ Laterite

Partly overlying the bed rock is a lateritic soil/lateritic cover, which are found in the valleys, depressions and flat land being used for cultivation. Laterite is not fairly developed locally, both in extension and thickness. From the observations made in the numerous water wells existing in the area, Lateritic soil/ Laterite thickness ranges from a few meters to a maximum of 8 meters.

Gneiss

The predominant rock type is peninsular gneiss with its typical banding of felsic and mafic minerals. Felsic bands, due to their mineralogical composition, are light in colour and essentially made of quartz, plagioclase and potash feldspars. The dark bands are called mafic bands due to presence of ferromagnesian minerasls like amphibole, pyroxene and little biotite.

Felsic and mafic bands are homogeneously distributed, each type representing about half of the whole rock mass. The banding pattern ranges from few to 20 centimeters and with its varying undulation, it is difficult to consider a general or



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representative orientation. The banding pattern is characterized by micro-structures such as folds and micro faults and they do not impact on the strength of the rock. In boreholes, banding does not represent an important source of joints and the coring process did not create artificial joints on limits of bands. This observation allows to consider gneiss as homogenous at the macroscopical scale say for the purpose of excavation.

Granite

Two types of granite are found in the area: Porphyry Granite and Iso-granular Granite.Porphyry granite does not exist at a large scale and this litho-unit is restricted to intrusions inside the gneissic rock mass. These are acid granites with predominant felsic minerals like quartz and feldspar. The name “porphyry” is owing to the presence of large plagioclase crystals, upto 5 centimeters.

Except for the grain size, isogranular granite is similar to porphyry granite with a minor increase of mafic minerals percentage, essentially micas. Plagioclase feldspars do not appear as large crystals and all the minerals are almost similar in grain size (few mm). Contacts between gneiss and the granite do not indicate weakness zones as they are sealed, tight and difficult to break with hammer or in the cores. Altered rocks Two types of alterations were observed during surface mapping and core logging namely weathering and hydrothermal alteration.

i) Weathering

The weathering zone is more developed when the gneiss is overlain by a laterite cover. This is observed in water wells where the gneiss is fairly weathered while the joints and the structure can be easily recognized. The thickness of the weathered zone are about 2 meters. The transition from weathered gneiss to fresh one is generally sharp. A few slightly weathered portions of gneiss are found in deeper cores, owing to inflow of meteoric waters along open joints.

ii) Hydrothermal alteration

Hydrothermal alteration is visible only on cores in few sections. It appears as joints filled with yellowish to whitish mineral encrustation. Macroscopically, these



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materials are identified as carbonate (calcite), clay and silica (quartz or amorphous silica). Hydrothermal joints have been observed in the deepest section of some cores. These joints are almost vertical and sometimes open. Hydrothermal fluids have deposited the filling material but have also slightly modified the mineral assemblage of the walls and the gneiss becomes slightly discoloured (feldspars become yellowish to greenish and pinkish) on a few mm to cm scale. These chemical changes, revealed by a change of colour generally affect the strength of the matrix since feldspars are more affected than other minerals (such as quartz which remains very slightly affected). Felspars are frequent and appear with quite big crystals so they largely impact on strength characteristics. Since, hydrothermal alteration is only slightly developed and only concentrated along joints with filling the strength reduction effect is very limited, in terms of location and also magnitude.

2.4.9 Tectonics

Three main striking features have been observed during the geological mapping:

I. N010 °E oriented depressed areas, essentially in the NW part of the site II. N160 °E oriented ridges and depressed zones of gneiss III. N110 °E central valley. In addition to the above near vertical joint sets, presence of a sub horizontal joint with orientation N 600 E is also observed.

The undulating topographic surface is attributable to the ridges and the associated depressions / valleys. The ridges are basically outcrops of fresh gneiss and represent roughly 50 % of the covered area with a typical shape of an elephant’s back. The study through satellite images of the area confirms the terrain configuration. In general, the depression / valley areas are represented by lateritic soil and paddy fields.

The most important feature of the area is the E-W central valley. It is characterised by its linear, narrow and dissymmetrical disposition. The azimuth of the valley is N110°E. During the DFR studies, the dis-symmetry of the valley along with the core logging of PB-5 borehole suggested a syn-tectonic fault transecting the area. However, based on the over all geological assessment during the supplementary investigation campaign the central valley has been inferred as a structural/ topographic lineament. Further, the selected site is located to the north east of the inferred lineament and no major structural feature is expected within the location of the underground storage facilities.



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2.4.10 Discontinuities

As seen from surface observations in quarries, very few discontinuities are reported. They have been classified as textural and structural ones.

Textural discontinuities are foliations or banding observed in the gneissic rock due to the presence of white felsic and dark mafic minerals in alternate manner. Globally it seems that the gneiss in the area has a general banding oriented E-W ( N110 E ) with a steep dip of 850 towards N. Away from this very general disposition, various orientations and dipping are found, with numerous micro structures such as micro folds and micro faults.

Structural discontinuities such as dykes, lineaments and joints are reported considering the over all area covered during DFR studies, however at the site area of the underground facilities, no major structural weakness zone is expected.

Surface engineering geological mapping of rock outcrops and the excavation mapping of the phase I underground facilities reveal the following predominant joint sets in the site area:

• N010°E dipping 850 towards East with a varying degree of spacing. • N110°E dipping 850 towards South with a varying degree of spacing. • N160°E dipping 850 towards East with a varying degree of spacing. • N60°E dipping 150 towards East / West with a varying spacing .

These four predominant joint sets are most developed; locally affected by hydrothermal alteration with mineral fillings / coating; and slightly “open”. Along with the foliation plane, these joints have induced differential weathering of the gneissic terrain and contributed to the undulating topography of the site.

Linear parallel depressions are reported in the north western part of the area trending N10°E-S10°W. An inclined borehole SPBH3 was drilled to investigate this depression. The drill cores revealed closely spaced joint sets between 117m to 150m drill depth. When these closely spaced joint sets were projected to surface they fall in the above depression found between hills. The joints are oriented N10°E and are subvertical (slight inclination towards east) and are found to be water bearing as is evident in the electrical resistivity survey.



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2.5 HYDRO-GEOLOGY

This document summarizes the hydro-geological results of various investigations under taken during the detailed feasibility studies (2005) in this area and subsequent supplementary investigations (2009) during bid stage of phase I site and all other additional investigations in the year 2010 before construction of phase I storage site. This document also incorporates the experience gained from the excavation of the phase I storage site which is under construction now. The intent of this section is to outline the results of the investigation campaign and all the available data from the existing storage site under construction to develop a hydro-geological model of the site.

2.5.1 Investigation Campaign

The following hydro geological investigation studies are included in this DPR.

• Single well hydraulic packer tests in core drills involving short duration tests using double packer system;

• Single well hydraulic packer tests in core drills involving long duration test per core hole using single packer system;

• Multiple well piezometric interference test; • Chemical analysis of water samples; • Hydro-geological monitoring of existing investigation holes and monitoring

wells.

Out of the six investigation coreholes (PB-1,2,3,4,5 & 6) carried out during DFR stage (2005), two inclined coreholes (PB5 and PB6) falls near the proposed project area. Hydro-geological tests were carried out in these coreholes, the results of which have been taken in these studies.

During supplementary investigation stage (2009), further six vertical coreholes (SPBH1, 2, 3, 4, 5 and 6) were drilled in the existing storage facility situated north west to the present proposed project site. However, the hydro geological characteristics will not vary very much between the two sites. Water pressure tests (short and long duration tests) were carried out in all the coreholes which have been taken in the present DFR studies.

Further, additional investigations were carried out in the Phase-I storage facility for identifying possible water bearing and conductive zones along the indicated lineaments from the satellite studies. All of them were inclined core holes, since all the major joints are found to be almost dipping vertically and missed most of the vertical coreholes drilled earlier. Total 14 coreholes (APAH1, 2, 3, 4, 5 & 8



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and APBH1, 2, 3, 4, 5, 9,10 & 11) were drilled including two coreholes (APBH9,10) for the shafts of the Phase-I storage project. Water pressure tests (short and long duration tests) were conducted in all these boreholes. The results from all the above investigations have been considered in the present study.

Apart from these coreholes; few monitoring wells were also drilled for permanent monitoring of ground water levels. However these are destructive holes and not investigative and are not included in these investigation studies. Ground water levels have also been measured from all the investigation holes drilled during 2009 and 2010 investigations.

Apart from the above investigations, three piezometric interference tests were also carried out. Between corehole PB5 and boreholes PS-2, OP-5, OP-6 and OP-10 in the fault valley to the west during DFR (2005).

The following interference tests were performed during investigation for existing phase I storage site (2010):

Between core hole APAH5 and coreholes APAH1, SPBH3, APAH8 and SPBH1. Between core hole APBH11 and coreholes APAH4, APAH5 and APAH3. Between core hole APBH1 and coreholes APBH10, APBH2, APBH9, SPBH1and APBH5.

2.5.2 Hydro geological Tests

Out of the six coreholes drilled in 2005 DFR stage, hydro-geological test results of one coreholes (PB-6) falls closer to the proposed layout and one corehole (PB-5) falls in the paddy field valley west of the proposed layout. (a) Short and Long Duration Water Pressure Tests The investigations involved water pressure tests in coreholes comprising short section and long section tests. Short sections were typically of 12 m each. These were either Lugeon tests or Injection-fall off tests using double packer. The packers sealed a portion of the corehole on both end of the test section.The tests covered the entire length of the core hole during various number of tests in rock.



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After completion of the short section tests, a long duration test was carried out in longer test sections in each corehole. These were Injection-fall off test. A single packer sealed the top of the test section in core hole. The maximum length of this test section is about 100m. Location of packer/length of test section in rock was decided as per the geological logging of core holes.

The following number of water pressure tests were conducted during DFR (2005) investigations:

Corehole Lugeon test Injection fall-off

Short duration test Injection fall-off Long duration test

PB-5 3 4 - PB-6 1 7 1 Note: Owing to high flow-rate and very fast pressure drop, only Lugeon test was performed with a long interval in corehole PB-5 (from 33 to 95.4 m drilled). A permeable fault was encountered during drilling at depth between -54m to -68 m below sea level. The corehole PB-5 represents central fault valley of paddy fields.

The following number of water pressure tests were conducted during supplementary investigations (2009) & mandatory investigation (2010):

Corehole

Short duration test

Injection fall-off Long duration test

SPBH-1 13 1 SPBH-2 12 1 SPBH-3 10 1 SPBH-4 9 1 SPBH-5 3 1 SPBH-6 9 1



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Corehole Short duration test Injection fall-off Long duration test

APAH-1 8 1 APAH-2 9 1 APAH-3 8 1 APAH-4 5 1 APAH-5 10 1 APAH-8 8 1 APBH-1 12 1 APBH-2 10 1 APBH-3 10 1 APBH-4 12 1 APBH-5 7 1 APBH-9 8 1 APBH-10 8 1 APBH-11 9 1

(b) Hydraulic Conductivity

A synthetic permeability profile from the test results of all the boreholes from DFR (2005) and supplementary investigations (2009) & mandatory investigation (2010) is presented in Figure 2.3 & Figure 2.4.

Permeability for the upper zone corresponding to lateritic or soil overburden and weathered bedrock seems to average at about 50 md (values range between 8 and 100 md) but the thickness of this zone is generally low.

The permeability profile (Figure 2.3) obtained from the hydro-geological tests in the corehole PB-5 show a low permeability (around 3 md) and a relatively high permeability (300 md) in the fractured zone occurred between -54M to -68 M below MSL. This corresponds to a fault. In long duration test, permeability of 50 md is reported. (A permeability of 1 md is equivalent to a hydraulic conductivity of about 10-8 m/s).

The permeability profile obtained from the hydro-geological tests in the corehole PB-6 show a low to very low permeability (lower than 0.6 md) and a relatively high permeability (12 md) in the upper 50m weathered zone. A fractured zone corresponding to the hydrothermal alteration zone is reported at the bottom of the borehole with permeable fissures but with limited extension. In long duration



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test, low permeability of 0.6 md is reported. (A permeability of 1 md is equivalent to a hydraulic conductivity of about 10-8 m/s).

In continuation, the interference tests indicate transmissivities in the order of 4000 to 40,000 mmd for the upper part of the weathered gneiss and extremely low permeability for the gneiss rock mass, equivalent to the above permeability.

The study results from the supplementary investigations (2009) of all the boreholes show a globally low permeability with locally high values in fractured zones or in the highly jointed zone encountered in few boreholes (Figure 2.4).

Boreholes SPBH-2, SPBH-4, SPBH-5 & SPBH-6 are representative othis globally low permeability. The joints in the rockmass are very few and the average permeability is very low of the order of 1 x 10 -10 m/s.

Boreholes PB2, SPBH1 and SPBH-3 is representative of jointed zone. The joints in these rockmass are open and permeable and the permeability varies between 1 x 10-10 m/s and 4 x 10-6.

The study results from of all the boreholes the mandatory investigations (2010) in the existing facility Figure 2.4) show a globally low permeability with locally high values in fractured zones or in the highly jointed zone and the dykes encountered in few boreholes. Permeability of the order of 5 x 10-6 m/sec was observed in few vertical fracture zones. The highest permeability was observed in borehole APBH-1 and APBH-10 of the order of 7 x 10-6 m/s representing sub-horizontal joints.

(c) Multiple Well Piezometric Interference Tests

Out of the envisaged three piezometric interference tests one multiple well interference test was conducted on PS3 bore hole system located close to core hole PB-4. Limited piezometric interferences were reported in the observation wells corresponding to PS3 – PB4 borehole system. The interference tests indicate transmissivities in the order of 4000 to 40,000 mmd (i.e. transmissivities of the order of 10-4 m2/sec) for the upper part of the weathered gneiss and extremely low permeability for the gneiss rock mass.

The interference tests in supplementary investigations in APAH5, APBH1 and APBH-11 indicate transmissivities of the order of 10-5 m2/sec to 10-4 m2/sec for the whole core hole (100m length) which includes laterite, weathered gneiss and jointed gneissic rock mass. The corehole APAH5 includes dolerite dyke



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intrusion. The corehole APBH1 includes sub-horizontal joint sets. The corehole APBH11 includes vertical joint sets as observed from the coreholes and later in tunnels and caverns during construction.

Thus it is observed that the area consists of dykes, sub-horizontal joint sets and vertical joint sets at some places and having high permeability of the order of 10-6 m/sec or more.

2.5.3 Ground Water Monitoring

Monitoring of the water table is being performed regularly for the existing coreholes and monitoring wells in the phase-I storage project since beginning of April 2010. It is observed that water level fluctuations are controlled by both natural and artificial parameters. Namely, withdrawal for irrigation by the farmers during the dry season (October to March) leads to a decrease of the water levels while the recharge during the monsoon period (June to September) leads to increase of the water levels. In general, it is observed that, the minimum water level fluctuates between 3 m to 15 m below ground level in a whole year.

Considering elevation of the wells, minimum hydraulic potentials in the wells range between +5 MSL (well near corehole PB-5) and +21 MSL.

During the monsoon period, the water levels in wells increased significantly to range between 0m and 4 m below ground level corresponding to hydraulic potentials between +8 MSL and +32 MSL.

2.5.4 Chemical Analysis

Chemical analyses including micro-biological tests were performed in water samples from existing wells and river for the following parameters viz. Iron, Manganese, Sulphate, Calcium, Magnesium, Nitrate, Bicarbonate, and pH and are tabulated below.



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Element Average

(mg/l) Minimum( mg/l) Maximum(mg/l)

Iron 0.50 0.14 2.12 Manganese BDL BDL BDL Sulphate 4.53 0 37.49 Calcium 7.86 1.07 41.49 Magnesium 2.70 0.85 11.32 Nitrate 0.17 0.05 0.29 Bicarbonate 41.75 24.4 122.0 Value of pH between 5.2 and 7.3 Note 1. BDL: Below Detection Limit 2. The most significant concentration of ions is reported in a sample from a submersible pump near PB-6 with 42 mg/l of Ca++, 122 mg/l of HC03-- and 38 mg/l of SO4--. The other parameters show normal values allowable for domestic household use.

2.5.5 Others

Site specific meteorological data such as barometric pressure, ambient temperature, and rainfall are as follows:

Maximum Barometric Pressure 1002 mbar (January) Minimum Barometric Pressure 994 mbar (May) Average annual temperature 27°C Maximum temperature 39°C Minimum temperature 16°C Maximum monthly average temp 31°C Minimum monthly average temp 23°C Annual average rainfall 4000 mm Maximum monthly rainfall 1320 mm Minimum monthly rainfall 0 mm Maximum daily rainfall 270 mm

No major floods have been reported in the area.



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2.5.6 Hydro-Geological Model

The topography of the area exhibits an undulatory hilly terrain traversedby a narrow central valley oriented roughly east-west. The fringing plateaus on either side have an elevation difference of about 20 m. The existing facility of the phase -I is in the northern flank of this valley. This central valley gets abruptly terminated to the east and are flanked by plateau on the eastern side. The proposed phase –II project is east of this central valley in this plateau. The plateaus and the flanks towards the valley are characterised by a number of gneissic hilly outcrops orientated North–South with an elevation of about 20 m. The central valley and the valleys at the north and south are characterised by vegetation and paddy fields.

The undulating topographic surface is attributable to the ridges and the associated depressions / valleys. The ridges are basically outcrops of fresh gneiss and represent roughly 50 % of the covered area with a typical shape of an elephant’s back. In general, the depression / valley areas are represented by lateritic outcrops and paddy fields.

Nala flow in the central valley and the valleys located both north and south of the site. The nala flowing in the central valley i.e at the west of the proposed site reaches Markodi River which flows further west of the site and drains to the Arabian sea at west. During rainy season (monsoon) the valleys are flooded and some water ponds do exist. These central and both north and south valleys are oriented roughly NNW- SSE and ENE-WSW and are characterized by lateritic soils, vegetation and paddy fields. The lineament map studies performed during this DFR (2012) also corroborate this (A197-000-67-41-1011) and show that these pattern do exist in this whole region of few square kilometers. As per the available meteorological data, the average rainfall in this region is about 4000 mm per year. The evaporation data for this region is reported to be about more than 50%. The topography of the area leads to heavy surface runoff towards the valley at north, south and west. The drainage pattern is dendritic to trellis. About 50% of the surface runoff is flowing towards valley at the south and the rest towards valley at north and west.

The site is characterized by a thin layer of lateritic or soil material, followed by a thin layer of weathered rock and subsequently hard gneiss/granite with a low to very low hydraulic conductivity. In addition there is a large area of exposed rocks with few joints. In literature it is reported that the average recharge in hard rocks in Peninsular India is of the order of 10% of the precipitation. However at the site the rock is massive with few joints and limited soil cover with large surface



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runoff. In view of the above the recharge is likely to be between 1 to 5% of 4000 mm per year. Farmers have shallow wells directly connected to the lateritic cover and to the weathered bedrock. The aquifer supply is inferred to be mainly from rain infiltration.

Groundwater in the basement rock is contained in fractures such as joint system or jointed veins or fractures but over all the formation is considered to be an extremely poor water bearing aquifer (i.e. very low storativity and high sensitivity to drought or water abstraction).

The permeability distribution in the rock mass essentially depends on joints characteristics (width, infilling materials, etc.). The very low average permeability value measured at site indicates very low joint density of the formation, and confirms that the gneiss matrix permeability is extremely low. But there are few open joints along the NW and EW lineaments and sub-parellel to them having extremely high permeability.

Based on the all the investigation results, a conceptual geological model with respect to ground water of the Padur site area is prepared. The summary of the geology of the site is given below:

Top soil Above bed rock, a thin veneer of soil and at places lateritic soil is found. But these are not fairly developed, both in extension and thickness. They are found in the valleys, depressions and flat land being used for cultivation. Its thickness ranges from a few meters to a maximum of 8 meters. Water bearing formations are restricted to the thin veneer of the lateritic soil/or followed by the weathered bedrock. Farmers have dug shallow wells in the lateritic soil and slightly inside the weathered bedrock.

Bed rock The predominant rock type in the area is peninsular gneiss and occasional granite intrusion at few places. The bedrock is weathered at the top few meters ranging from 1 - 5 meters. Below which the bedrock is generally fresh and hardly jointed. Intrusive granites present are found to be devoid of joints and massive at some places.

Geological features/jointed zone in the bed rock



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Based on the lineaments study in the area and the subsurface investigation including hydro test, following features are probably intersecting the project facility.

• Vertical jointed zone: running app. north south (NNW – SSE) direction. • Vertical jointed zone: running almost east-west direction. • Sub-horizontal open joints: running ENE direction and dipping both north and

south. • Vertical dykes parallel to the lineament NNW. • Vertical dykes parallel to the lineament east-west direction. • Fault zone in the north west side of the facility however it lies outside of the

project.

2.5.7 Conceptual Hydro-geological Model

Hydraulic conductivity profiles from all the short and long duration water pressure tests are presented from Figure 2.3 & 2.4. The hydro-geological properties of each litho unit are described below:

Soil No hydraulic conductivity tests were carried out in the upper zone corresponding to lateritic soil/ overburden because of the placement of casing during drilling. However the thickness of this zone is generally low and is expected to have high permeability.

Weathered bedrock Hydraulic conductivity for the weathered bedrock ranges between 1 x10-10 - 2 x10-6 m/s seems to average at about 2 x10-8m/s but the thickness of this zone is small in the range of 1-5m.

Fresh Bedrock The study results from all the boreholes show a globally low hydraulic conductivity for the fresh bed rock (consisting of gneisses/granites) with locally high values in the jointed zones. The water pressure tests also suggest that there is no difference in hydraulic properties for the rock mass at cavern level compared to the rock mass as a whole with the exception being some horizontal joints.



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Geological features / jointed zones in the bedrock The fresh bedrock is intersected by jointed zone / dyke contact zone as described in the Geological model. These features are either open or highly conductive. The general hydro-geological properties based on the experience gained in the existing construction project are given below:

• The vertical jointed zone running north-south (NNW-SSE) directions are all

open and are conductive as high as 10-6 to 10-7 m/sec. • The vertical jointed zone running east west directions are all relatively open

and are moderatively conductive about 10-7 m/sec. • Sub-horizontal joints running ENE direction are fully penned and are highly

conductive as much as 10-4 m/sec. • The vertical dykes parallel to the lineament NNW are highly conductive along

the contacts and some difficulty in grouting could be faced. • The vertical dykes parallel to the lineament east-west are relatively tight.

However their contact zone with the bedrock may be low conductive at some places.

• The fault zone in the north west of the facility is highly permeable could be as high as 10-4 m/sec however, they lie outside the cavern layout but could influence the water flow and recharge both natural and artificial.

2.5.8 Permeability Distribution Model

The hydro-geological data were segregated according to the vertical lineaments, horizontal joints and dykes intersected on the boreholes outlined in the above conceptual hydro-geological model. The data were synthesized and analyzed and the following permeability distribution model was prepared:

Lowest

K m/sec Highest K m/sec

Geom. Mean K Range (m/sec) at cavern level

Grouted K (m/sec)

Remarks

Main Rock mass zone 4x10-11 2x10-9 1.25 x 10-10 -

1.5x10-10 -----------

All Vertical joints 1x10-10 5X10-6 2x10-7 110-7 Dykes are

also included. All Sub-horizontal joints

1X10-8 7X10-6 2x10-6 25x10-8



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Note: 1. It is assumed that all vertical joints will be grouted to 10-7 m/sec. 2. It is assumed that all sub-horizontal joints will be grouted to 5x10-7m/sec. However as the horizontal joints only intersect part of cavern section, an average grout permeability of 5x10-8m/sec is assumed in the whole section.

Based on the experience in phase I storage project, the length of cavern section likely to be influenced by highly permeable vertical dykes and fracture zones and sub-horizontal joint zones are given in the following table.

Length of section affected by high permeable zone in each cavern:

Caverns

Length of section affected by highly permeable Vertical Joints (in meters)

Length of section affected by highly permeable Sub-

horizontal joints (in meters)

Rock mass

Unit A1 150 m 100 m Rest Unit A2 150 m 50 m Unit B1 150 m 50 m Unit B2 150 m 100 m

Applied K in the model

10-7 m/sec 5x10-8 m/sec

1.5x 10-10 m/sec



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2.5.9 Hydro-Geological Design

(a) Water Curtain System

The storage facility consists of eight parallel caverns / galleries with unitary length of about 780 m and a pillar width of 30m within unit and about 70 m Intra unit. The caverns are designed with a dimension of 30m height X 20m width. The cavern roof elevation is designed at - 35 MSL and the cavern floor elevation at ≥ -65 MSL with a longitudinal slopping bed at 1: 250.

A horizontal water curtain is constructed 20 m above the cavern roof (designed elevation is -15 MSL for WC boreholes). Initial borehole spacing is constant and equal to 10 meters. Water curtain galleries are oriented parallel to the caverns (N700E). The horizontal water curtain is oriented in a manner to have the water curtain holes perpendicular to the most pervious joint sets i.e. NS and EW joint sets; with water curtain holes oriented N1500E and N2400E to intersect the pervious joint set.

Water curtain boreholes are drilled perpendicular to the water curtain gallery at a spacing of 10 m. Length of boreholes is limited within 100m in order to avoid deviation, generally encountered in sub-horizontal holes. Water curtain boreholes are to be drilled approximately 1 m above the water gallery invert.

During construction period, the water curtain boreholes will be pressurized with water through the main water supply line in the water curtain gallery. At the end of the construction, the boreholes will be disconnected and open and the injection line will be dismantled before the flooding of the water curtain gallery. Depending on the hydrogeological observations collected at the end of the construction and during the Acceptance Test, a permanent water supply of the water curtain could be necessary. This water supply will be performed either trough the access tunnel or a dedicated monitoring well connecting the water curtain gallery to the surface.

The water curtain injection water will have to be fresh and clean water with low value of suspended materials and very low value or lack of bacteria in order to avoid water curtain clogging.

(b) Numerical Modeling

Finite element model studies were carried out to check the flow pattern around the caverns to confirm hydraulic containment and estimate seepage rates based on all the available data.



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The following parameters are to be considered:

a. Maximum operating pressure (1.3 bar g) b. Hydraulic margin of at least 20m above the maximum operating pressure c. Requirement of hydraulic gradient greater than 1 at cavern roof level d. Provision of water curtain above the cavern with boreholes charged to a

head equivalent to (+5) msl with water curtain curtain gallery at -15 MSL.

The results obtained from the above study indicate that the essential containment criterion of hydraulic gradient of ≥ 1 is satisfied (see Figure 2.2). The flow patterns observed around the cavern units shows all flows diverted towards the cavern.

Figure 2.2 Typical flow pattern

(c) seepage estimates

The water seepage during construction and operation of the storage units were calculated based on the above finite element seepage analysis studies and the experience from phase 1 storage project. The permeability considered for the analysis is based on the permeability distribution model discussed above.

The summary of the assumptions considered in the model are as follows:

1. K (rock mass) = 1.5 x 10-10 m/s 2. K (vert. joints)= 10-7 m/s (achievable after grouting) 3. K (hz. Joints) = 5 x 10-8 m/s (Based on permeability of sub-horizontal joints

intersecting cavern with high K and is assumed to be grouted up to average grout permeability of 5x10-8 m/s in a section of one meter)

4. Average length of section (LAvg) affected by geological structures.

A B



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1. Total seepage Total seepage during construction & operation at Pmin = 60 m3/hr Total seepage during operation at Pmax = 45 m3/hr Maximum seepage in a unit during operation = 20 m3/hr

2. Water curtain make-up Requirement:

Water requirement for water curtain supply during construction and operation at Pmin = 60 m3/hr. Water requirement for water curtain supply during operation at Pmax = 40 m3/hr.

3. ETP Requirement:

The capacity of Effluent treatment plant (ETP) required for treatment of seepage water during operation is estimated at 60 m3/hr.

2.5.10 Discussion

• The caverns are located in the competent rockmass with a low hydraulic conductivity. However joints and dykes with high permeability will exist at few places locally, which will affect the hydrogeological conditions.

• Dykes, fracture zones, shear seams and other highly jointed zone will intersect few parts of the cavern and are expected to encounter higher inflows and may require extensive pre-grouting.



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Figure 2.3 – Permeability test results during DPR (2005) stage



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Figure 2.4 – Permeability test results during Supplementary Investigation and construction stage (2009 & 2010) of phase I project



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2.6 GEO-TECHNICAL MODELS This section outlines the analysis and design of the underground structures and support recommendations to obtain the safety, stability and economy of the project. The formulation of geotechnical models may be grouped under the following headings:

2.6.1 Determination of Input Data:

Determination of input data, which comprises of getting the geological structure as well as rock and rock mass properties, is done through the planning and conducting the site investigation. As a result of the undertaken geotechnical investigation, the geological features and engineering parameters, which are going to have an impact on the design and construction of the project, are set as below: • Geological structure • Natural stress field • Rock mass properties



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(a) Geological structures:

The geological structural model include inferred major structural features such as joints, faults, dykes, bedding planes, zone of alteration etc based on the boreholes, exposure mapping , petro logical descriptions and geophysical survey.

From the various geological investigation campaign performed during phase I underground storage facilities reveal the following predominant joint sets in the site area: • N010°E dipping 850 towards East. • N110°E dipping 850 towards South. • N160°E dipping 850 towards East. • N60°E dipping 150 towards East / West.

These four predominant joint sets are most developed; locally affected by hydrothermal alteration with mineral fillings / coating; and slightly “open”. Natural stress field

(b) Natural Field Stress

Vertical stress

The overburden above the cavern area is derived from the satellite imagery of the selected site. The cavern gallery roof is situated at –35 m below mean sea level and the contour level in the area varies from +15 to +40. On an assumption of an average contour of +30, the rock cover for the analysis at the crown of the long caverns will be up to approximately 65 m. With a density of 2.7 t/m3, the maximum vertical stress is approximately 2 MPa.

Horizontal stress

The stress measurement were carried out in two-bore holes namely PB1 & PB 6 drilled with NX size. The interpretation took into account hydro fracturing data from PBI (without orientation as the tool was struck and had to be abandoned in the hole) and hydro fracturing value as well as orientation in PB6.

The detailed analysis of the data gives the following results for the virgin stress field (unit in MPa): Sh=0.075 + 0.0575 . z SH = 0.475 + 0.1025 . z SV = 0.027* z



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With Sh the minor horizontal stress, SH the major horizontal stress and SV the vertical stress and z the depth in meter below ground level. The mean orientation of the induced fractures in borehole PB 6 suggests a direction of N156E (±14 deg) for SH. The horizontal to vertical stress ratio is about 2 for the minor horizontal stress (Sh/SV) and about 4 for the major horizontal stress (SH/SV) at the depth of the storage.

Stress Measurement

(c) Rock Mass Properties

Rock contains fractures, which render it structural discontinuity. There is a clear distinction between intact rock and rock mass. The rock mass is the total in-situ medium containing bedding planes, faults and others structural features. Section 2.3 compiles all the test result of intact rock conducted in laboratory to arrive at the upper bound values of rock paramteters. Those value, cannot be used as an input for numerical analysis programs, however, can be used as an input to obtain the rock mass properties determined by RocLab. RocLab is a software program for determining rock mass strength parameters, based on the generalized Hoek-Brown failure criterion. The following inputs are required to obtain the rock mass properties in RocLab.

• Unconfined compressive strength of intact rock, σci • The intact rock parameter, mi • The geological strength index, GSI • The disturbance factor, D • The Intact rock modulus, Ei

The value of unconfined compressive strength of intact rock & Intact rock modulus can be obtained from the laboratory test results. mi is the material constant of intact rock and D is the disturbance factor based on the excavation pattern performed at site.

Stress Magnitude, MPa

Direction Stress Ratio Ko

Sv 2 Vertical SH 7.2 N156E ≈ 4 Sh 3.8 Perpendicular to SH ≈ 2



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Geological strength index, GSI

The Geological Strength Index (GSI) provides a system for estimating the reduction in rock mass strength for different geological conditions as identified by field observations. The rock mass classification is straight forward and it is based on the visual impression of the rock structure, in terms of blockiness, and the surface condition indicated by joint roughness and alteration (Table 3, from Hoek & Brown). The combination of these two parameters provide a basis for providing a wide range of rock mass type, with diversified rock structure ranging from very tightly interlocked strong rock fragments to heavily crushed rock mass. Based on the rock mass description the value of GSI is estimated from the contour as given in Figure 2.5.

Figure 2.5 : Geological Strength Index



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The majority of the excavation work is expected to be made in the rock mass with an average GSI value greater than 80 to 90 i.e. “good/v.good” rock condition.Once the Geological Strength Index (GSI) has been estimated, the parameters that describe the rock mass strength characteristics are calculated by utilising the Roclab software (Rocscience). The results of the calculation are tabulated 2.11.

Table 2.11: Rock Mass Parameters Parameter Value Remark GSI 80 to 90 mi 28 Gneiss Rock mass Compressive strength (MPa)

45 to 75 Rockmass, H-B

Friction Angle (0) 55 to 65 Rockmass, M-C Cohesion (MPa) 4 to 6.0 Rockmass, M-C

In situ deformation modulus

Grimstad and Barton (1993) have found good agreement between measured displacements and predictions from numerical analyses using in situ deformation modulus values estimated from: Em = 25log10Q. The modulus values ranges from 12-68 GPa with an average value of 50 GPa.

From rock lab results (Figure 2.6), the typical value of deformation modulus has been taken 40GPa.

Figure 2.6 : Rock lab Test Results



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Summary of design input: Based on the input data from the site investigations and subsequent analysis, the following intact rock and rock mass parameter design values, as well as stress levels as shown in the table 2.12, have been determined.

Table 2.12: Design Input from Investigations

Property Value Remark

Intact Rock

Bulk density (t/m3) 2.68 ± 0.75 Mean ± Standard deviation

Uniaxial compressive strength, UCS (MPa) 133 ± 43 Mean ± Standard

deviation

Tensile strength (MPa) 6.7 ± 2.4 Mean ± Standard deviation (indirect tensile strength test)

Young’s modulus(GPa) 62 ± 4.0 Mean ± Standard deviation

Poisson’s ratio 0.23 Form laboratory tests

mi 28 For Gneiss

Rock stresses at cavern roof

Vertical stress (MPa) 1.4 to 2.0 Rock cover varies from 15 to 40m

Max horizontal stress (MPa) 5.5 to 8.0 Rock cover varies from 15

to 40m

Min horizontal stress (MPa) 3 to 4.0 Rock cover varies from 15

to 40m

Rock Mass (Typical Value at Cavern Level)

GSI 85 Mean GSI is 90

Rock-mass strength (MPa) 50 Rock Lab, H&B

Friction angle (0) 65 Rock Lab and correlations

Cohesion (MPa) 4.7 Rock Lab and correlations

Deformation modulus (GPa) 40 Rock lab and correlations



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2.6.2 Design method:

A consistent design for rock caverns mixes the following three methods:

• Empirical method (Rock Mass classification & comparative approaches) • Analytical method (numerical and physical models, failure criteria) • Observational (Field measurements).

(a) Empirical method (Rock Mass classification & comparative approaches)

Rock mass classification schemes have been developing for over 100 years and has attempted to formalize an empirical approach to tunnel design, in particular for determining support requirements. Rock mass classification has the following general aim in an engineering application:

a) To divide a particular rock mass into groups of similar behaviour; b) To provide a basis for understanding the characteristics of each group; c) To yield quantitative data for engineering design; and d) To provide a common basis for communication.

Q-system according to Barton et al (1993) have been used for prognosis of rock mass during the present study.

Q-system On the basis of an evaluation of a large number of case histories of underground excavations, Barton et al (1974) of the Norwegian Geotechnical Institute proposed a Tunnelling Quality Index (Q) for the determination of rock mass characteristics and tunnel support requirements. The numerical value of the index Q varies on a logarithmic scale from 0.001 to a maximum of 1,000 and is defined by:

Q = (RQD/Jn) x (Jr/Ja) x (Jw/SRF)

Where,RQD - Rock Quality Designation

Jn - joint set number Jr - joint roughness number Ja - joint alteration number Jw - joint water reduction factor SRF - stress reduction factor

Note : 1. At the tunnel cross-sections reduce the Q value to 1/3rd. 2. In view of the pressurization of water curtain tunnels Jw value to be taken considering high pressure conditions.



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The Q-value can be considered to be a function of three parameters, which are crude measures of: a) Block size (RQD/Jn) b) Inter-block shear strength (Jr/Ja) c) Active stress (Jw/SRF)

In relating the value of the index Q to the stability and support requirements of underground excavations, Barton et al (1993) defined an additional parameter which they called the Equivalent Dimension, De, of the excavation. This dimension is obtained by dividing the span, diameter or wall height of the excavation by a quantity called the Excavation Support Ratio, ESR. Hence:

De = Excavation span, diameter or height (m)/Excavation Support Ratio, ESR

The value of ESR is related to the intended use of the excavation and to the degree of security, which is demanded of the support system installed to maintain the stability of the excavation. Barton et al (1993) suggest the following values:

Table 2.13 Recommended ESR Values

Q-classification

The following Q-value parameters have been estimated (Table 2.14) from the field mapping and the mapping of cores from the investigation done at Phase-1 stage and the present DFR stage.The values have been selected considering geotechnical conditions in plot area.



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Table 2.14: Q values in cavern area

Parameters Range Remarks RQD 80-100 Good to Excellent Jn 6-1 Two joint sets + Random to un

jointed Jr 2-4 Smooth undulating to

discontinuous joints Ja 4-1.0 Low friction coating to joints in

contact Jw 0.5-1.0 Dry to wet condition SRF 1.0 Medium stresses Q 3.3 -530 Poor to Excellent (typical value of

Q>>40) ESR 1.3 Storage rooms De 15.4 B/ESR (B = 20 ), roof De 23.08 H/ESR (H = 30 ), wall

The majority of the excavation work is expected to be made in the rockmass with an average Q value greater than 40, corresponding to “good/excellent” rock. The P-wave values from the Seismic Refraction, correspond to Q-values with in this range, according to the following equation, Barton (1991) Q= 10(Vp-3500)/1000 which gives a Q-value greater than 40 when using an average P-wave velocity greater then 5000 m/s in the sound rock.

(b) Analytical method

(i) Numerical Analysis

The total stress situation in the vicinity of an excavation depends on:

a) The in situ stress field b) The orientation of the excavation with respect to the in situ stress field c) The geometry of the excavation d) The excavation stages

The Stress analysis is carried out to analyze the following

a) Stress/Strain situation and distribution in the rock mass b) State and extension of possible yielding zones. c) Pillar stresses d) Rock displacements, internal stresses and forces



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The rock formation is considered as a homogenous and elasto-plastic material. 2D plane strain analysis was carried out using Phase2 FEM software using the following mechanical parameters as input.

Rockmass Parameters Adopted for analysis

a) Unit weight 0.027 MN/m3 b) Material type: isotropic c) Young's modulus 40 GPa d) Poisson's ratio 0.23 e) Compressive strength 133 MPa f) m parameter: 13.707, s parameter: 0.1353, a parameter 0.500 g) Material type: Plastic h) Dilation parameter : 0 i) Residual mr : 1, j) sr : 0 k) ar: 0

The residual parameter has been taken based on the rock mass and type of failure. Assuming the rock as a massive in view of the GSI close of 85, the high stress shall result in intact rock failure (brittle type).

Field Stress Conditions Adopted

a) Field stress: gravity b) Ground surface elevation: 70 m of rock cover is considered above the cavern

roof. c) Unit weight of overburden: 0.027 MN/m3 d) Stress ratio (horizontal:vertical in-plane): 4 e) Stress ratio (horizontal:vertical out-of-plane): 2

Phase2.0 Software

The numerical analysis is performed by using the software Phase2.0. It is a two-dimensional continuum modeling approach for simulating the behaviour of discontinuous rock mass.

Model The analysis was performed using a model of an unsupported excavation to determine the intrinsic stability limits of the rock mass. The Generalized Hoek-Brown failure criterion is used for analysis.Three noded triangular elements are



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adopted for generating the mesh. The assumed dimensions of the adopted section is as follows

Height : 30 m Width : 20 m Shape : D-shaped No. of caverns : 8 Pillar width in a storage unit : 30 m Spacing between the units : 100 m Strength Criterion: The rock mass are assigned properties obeying the linear-elastic perfectly plastic law where Generalized Hoek-Brown Strength Criterion is considered as follows:

Where is a reduced value of the material constant , given by

and are constants for the rock mass given by the following relationships:

GSI = Geological Strength index D is the disturbance factor. Boundary Condition Boundary conditions adopted are top surface of model is free, nodes in vertical edges of the model are fixed in X-direction and the bottom nodes are fixed in both X and Y directions. Pore pressure is not considered in the analysis.The right hand side boundary of the model is 50 m away from the cavern wall because of the symmetry of the storage units. The distance between cavern and left side model boundary is taken as ten times the width of the excavation to eliminate the effect of displacement and stress on the boundary.



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Figure 2.7 Mesh and Boundary Conditions Adopted for analysis

Results and Conclusions: Principal Stress:

Figure 2.8 Maximum Principal Stress Contours

• Maximum principal stress observed at the crown level is close to 18MPa and

that at the invert level is of a magnitude of 18 MPa. • Maximum principal stress at the crown of 16 to 18 MPa, is of about two to

three times the magnitude of the in-situ stress, and approx. 30% of the rock mass strength.

• Stress levels around the cavern are moderate and acceptable and stability due to rock stresses will not be a problem.



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Yield Zone:

Figure 2.9 yield zone • The maximum yielding zone of about 2.0 m is observed in the penultimate

cavern walls. • Therefore, length of Rock bolt of 5m is sufficient.

Deformation

Figure 2.10 Total Displacement Contours

• Maximum total deformation is noted at the cavern walls of the end caverns and is of 8 mm and the max deformation in the roof is of 2.5 mm.

• This may be due to the influence of the magnitude and direction of the principal stresses.

• The overall displacements are relatively small and acceptable.



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Pillar Strength

Figure 2.11 Strength Factor Contours

• The maximum stress in the pillar is of 6 MPa magnitude which is much less

than the strength of the rock mass. • The minimum strength factor between the pillars is close to 3 which are

acceptable. • The minimum principal stress at the roof is kept compressive with a

magnitude less than the rock mass strength. Tensile stress of very low magnitude is developing around the end cavern walls; this stress is far less than the tensile strength of the rock mass.

Shear Stress

Figure 2.12 Maximum Shear Stress Contours



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• From the shear stress distribution it can be seen that the rock pillar between the caverns is in a triaxial compression state where the shear stress is very close to zero. This state ensures the stability of the pillar, since the major failure mechanism associated with rock pillars is shear failure. The same point is confirmed with the strength factor as the strength factor around the cavern excavation is greater than unity.

Conclusions: Based on the FEM analysis, it can be concluded that in-spite of the maximum stress perpendicular to cavern wall, the stresses around the cavern are very much less than the rock mass compressive strength and corresponding deformations are very small. Pillar stability will not be critical. In view of the low yielding zone, Rock bolt of 5m is sufficient.

(ii) Structurally controlled instability

In tunnels excavated in jointed rock masses at relatively shallow depth, the most common types of failure are those involving wedges falling from the roof or sliding out of the sidewalls of the openings. These wedges are formed by intersecting structural features, such as bedding planes and joints, which separate the rock mass into discrete but interlocked pieces. When a free face is created by the excavation of the opening, the restraint from the surrounding rock is removed. One or more of these wedges can fall or slide from the surface if the bounding planes are continuous or rock bridges along the discontinuities are broke After identification of the main joint sets carried out from core geological observation, the potential unstable wedges formed by the main gallery intersecting the identified joint sets are investigated using dedicated software namely UNWEDGE (Rocsciences).

UNWEDGE is designed for the analysis of the geometry and the stability of underground wedges defined by intersecting structural discontinuities (three maximum for UNWEDGE) in the rock mass surrounding an underground excavation. UNWEDGE is the preferred tool for maximum block analysis. The size and shape of the potential wedges in the rock mass surrounding the cavern depends upon the orientation of the discontinuities but also upon the orientation, shape and size of the cavern section. The efficiency of the proposed support patterns methods has been checked for the projected structural instability using the computer software. If the initial excavation works reveal any major differences between actual conditions and findings from the site investigation, the design may have to be amended accordingly.



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The leading parameters, which may lead to changes in the design, are:

a) Discontinuities liable to cause instability not previously suspected from the investigation works.

b) Locally disturbed rock conditions (e.g. thick weathered or broken strips) with alterations reaching the dimensions of the main galleries.

c) Previously undetected shear faults.

The main assumptions for the analysis are given below:

a) The rock mass density is taken equal to 2.7 t/m3. b) The joints are assumed to be planar and continuous. They are characterized

by a Mohr-Coulomb criterion with a joint cohesion of 0.0 MPa and a joint friction angle equal to 450.

c) Considering the UNWEDGE analysis, the beneficial effects of the in-situ stresses on the wedge stability are ignored in the analysis

d) The wedges are tetrahedral in nature, and defined by three intersecting discontinuities in UNWEDGE

e) Safe condition is assumed when safety factor is equal to or above 1.5 (safety factor below 1 implies wedge failure).

f) Maximum Persistence of the joint is taken as 10m.

Major Joint Sets Considered for the Analysis are tabulated as under :

Table 2.15 Joint Sets Joint set number Dip/Dip Direction 1 85/100 2 85/20 3 85/70 4 15/150

Orientation of the cavern is N70oE. Joint Properties Friction angle: 450 Cohesion: 0.0 MPa

Rock bolt Properties • Type: Grouted Dowel • Diameter : 25mm • Tensile capacity: 0.213 MN • Plate Capacity: 0.15 MN



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• Bond strength: 0.1 MN/m • Bond Length :100% of Bond Length • Shear Strength : 0.118MN • Minimum yield strength 500 MPa • Bolt Length: 5m • Orientation: Normal to Boundary • Pattern Spacing: in Plane 2.0 m • Pattern Spacing: out of Plane 2.0m • Pattern Spacing: out of Plane offset 0.0m

Results of UNWEDGE analysis

The aim of this analysis is the detection of the most unfavourable combination of joint sets. The wedges considered are the largest wedges which can be formed for the given geometrical conditions. The probability that such huge wedges occur is very low since the wedge size in actual rock mass is limited by the persistence and spacing of the discontinuities. Without Support: Summary of the unwedge results without support are given in table 2.16.Also the diagram showing details of wedge are presented in Fig 2.13, 2.14 & 2.15.

Table 2.16 Wedge Analysis

Joint Dip/Dip Direction

Comb. 1 (J1,J2,J3)

Comb. 2 (J1,J2,J4)

Comb. 3 (J1,J3,J4)

Comb. 4 (J2,J3,J4)

1 85/100 X X X 2 85/20 X X X 3 85/70 X X X 4 15150 X X X Not Relevant

Crown Wall Crown Wall Crown Wall Crown Wall Wedge Weight

(MN) 0.006 0.00

0 1.391 0.003 0.621 - 0.925 0.009

Apex Height (m)

- - 4.41 0.2 4.66 - 4.24 0.4

FOS Without Support

0.087 Stable 0.087 - 0.087 Stable



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Figure 2.13 Critical Wedges formed Joint Set (J1-J2-J4) without Support (Min. FOS 0.087)

Upper Left wedge [3] FS: 3.732 Weight: 0.003 MN Excavation Area: 1.73 m2 Apex Height: 0.20 m

Roof wedge [4] FS: 0.087 Weight: 1.391 MN Excavation Area: 37.63 m2 Apex Height: 4.41 m

Upper Right wedge [6] FS: 0.087 Weight: 0.375 MN Excavation Area: 23.54Apex Height: 2.04 m



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Figure 2.14 Critical Wedges formed Joint Set (J1-J3-J4) Without Support (Min. FOS 0.087)


Roof Wedge [6] FS: 0.087 Weight: 0.209 MN Excavation Area: 13.60 m2 Apex Height: 2.34 m

Floor wedge [6] FS: Stable Weight: 0.129MN Excavation Area: 10.7 m2 Apex Height: 1.48 m



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Figure 2.15 Critical Wedges formed Joint Set (J2-J3-J4) Without Support (Min.FOS 0.087)

Upper Right wedge [4] FS: 0.087 Weight: 0.276 MN Excavation Area: 17.14 m2 Apex Height: 2.10 m

Lower Left wedge [5] FS: 3.732 Weight: 0.009 MN Excavation Area: 2.38 m2 Apex Height: 0.40 m




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With Support: Summary of the unwedge results with support are given in table 2.17.The diagram showing details of wedge are presented in Figure 2.16,2.17 & 2.18.

Table 2.17 Wedge Analysis

Figure 2.16 Critical Wedges formed Joint Set (J1-J2-J4) with Support (Min. FOS 1.21)

Joint Dip/Dip Direction

Comb. 1 (J1,J2,J3)

Comb. 2 (J1,J2,J4)

Comb. 3 (J1,J3,J4)

Comb. 4 (J2,J3,J4)

1 85/100 X X X 2 85/20 X X X 3 85/70 X X X 4 15150 X X X Not Relevant

Crown Wall Crown Wall Crown Wall Crown

Wall

Wedge Weight (MN)

0.006 0.000

1.391 0.003 0.621 - 0.925 0.009

Apex Height (m)

- - 4.41 0.2 4.66 - 4.24 0.4

FOS Support 5m @ 1.5m c/c

1.92 Stable 2.47 - 1.54 Stable

Upper Left wedge [3] FS: 291.25 Weight: 0.003 MN Excavation Area: 1.73 m2 Apex Height: 0.20 m


Upper Right wedge [6] FS: 5.13 Weight: 0.375 MN Excavation Area: 23.54m2 Apex Height: 2.04 m



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Figure 2.17 Critical Wedges formed Joint Set (J1-J3-J4) With Support (Min. FOS 2.47)


Roof Wedge [6] FS: 3.31 Weight: 0.209 MN Excavation Area: 13.60 m2 Apex Height: 2.34 m

Floor wedge [5] FS: Stable Weight: 0.129MN Excavation Area: 10.7 m2 Apex Height: 1.48 m



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Figure 2.18 Critical Wedges formed Joint Set (J2-J3-J4) With Support (Min.FOS 1.54)

Upper Right wedge [4] FS: 4.91 Weight: 0.276 MN Excavation Area: 17.14 m2 Apex Height: 2.10 m

Lower Left wedge [5] FS: 206.94 Weight: 0.009 MN Excavation Area: 2.38 m2 Apex Height: 0.40 m




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Observations and Recommendations

a) The above results shows that very few wedges will be forming with J1-J2-J3 joint set combination as the all major joint sets are dipping vertical to sub vertical.

b) The wedge forming in the wall of the cavern is stable and the wedge formed in the roof (spring level) of the cavern is very narrow which can be stabilized by pattern bolting.

c) Results show that the critical wedge is formed with the combination of vertical joint set with horizontal bedding plane N60°E (combination J1-J2-J4,J1-J3-J4 & J2-J3-J4) .

d) At the crown, the wedge is formed with maximum apex height 4.66 m suggests that bolt length should be more than the wedge apex height. Therefore, minimum length of the bolt should be 5.0 m.

e) The results as obtained from the Unwedge analysis shows that a Factor of Safety greater than 1.5 can be achieved with rock support having length of 5 m and the rock bolt spacing of 2.0 m c/c in most of the case in the roof. No major wedge is formed are estimated in the wall.

f) In some roof wedge formed with the combination of J1-J2-J4 and J2-J3-J4, wherein the factor of safety is less than 1.5 with rock bolt spacing of 2.0m c/c, the spacing of the rock bolt needs to be densify from 2.0m c/c to 1.5 c/c.

g) Shotcrete has not been taken into consideration in the analysis. The application of shotcrete will invariably increase the factor of safety.

(c) Observational (Filed measurements)

Geotechnical Monitoring

Monitoring is a tool to check the validity of the assumption involved in conceptual models and values of rock mass properties adopted in design calculation. To check the rock mass response and as a consequence, adjust the overall design to take the remedial measures is an important aspect of monitoring.

Displacement of the rock mass shall be monitored with borehole extensometer and convergence measurement equipment (optical target). 5 optical targets on the roof and 3 on either side of the wall of the cavern shall be applied during each stage of excavation.



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2.6.3 ROCK SUPPORT DESIGN

Typical Rock Support

The typical rock support is based on untensioned, fully cement grouted, rock bolts (rebars) interacting with fibre-reinforced shotcrete. The installed support acts as a support-system by both reinforcing the rock mass and retaining broken rock. The main objective of reinforcing the rock mass is to strengthen it, and thus enabling the rock mass to support itself. The rock bolts are the main reinforcing elements, however, they also act as holding elements to tie the retaining elements (shotcrete) back to stable ground. The support philosophy is derived from extensive experience from similar cavern excavations.

This experience forms the basis for the empirical rock support design, which is derived from the various rock mass classifications, such as the Q-system. Consequently, the support recommendations given by the Q-system have been used for choosing the typical rock support, shown below. The indicative typical rock support for Padur is given in table 2.18 to 2.22 together with the corresponding rock mass classes (Q-values). The rock bolts are fully cement grouted, untensioned, rebars (25 mm diameter) with the indicative spacing as shown below. The shotcrete is fibre reinforced, with the indicative thickness as shown below.

Table 2.18 Typical rock support caverns

Cavern 20 X 20-30 m (W X H) Q-value Q>40 10<Q<40 4<Q<10 1<Q<4 Q<1

Support Type I-V.Good II-Good III - Fair IV- Poor V – V.Poor Crown Support Bolt length 5 m 5 m 5 m 5 m 5 m Shotcrete thickness 50 mm 50 mm 75 mm 100 mm 150 mm

Bolt spacing 2.5 2.0 1.75 1.5 1.5 Sidewall Support Bolt length 5 m 5 m 5 m 5 m 5 m Shotcrete thickness 50 50 75 mm 100 mm 150 mm

Bolt spacing SB* 2.5 2.0 1.75 1.5 * Spot Bolting Note:- Longer bolts of length of 8m may be required in some areas.



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Table 2.19 Typical rock support for water curtain tunnels

Q-value Q>4 1<Q<4 Q<1 Support Type I-III –Very good to Fair IV- Poor V – V.Poor Bolt length 2.5 m 3 m 3 m Shotcrete thickness 50 mm 50 mm 100 mm

Bolt spacing SB* 2.0 m 1.5 m Bolt length 2.5 m 3 m 3 m Shotcrete thickness 50 mm 50 mm** 100 mm

Bolt spacing SB* 2.0 m 1.5 m * Spot Bolting **If Required

Table 2.20 Typical rock support for Access tunnels and Cross Access Tunnels

Access Tunnel 8 X 12 m (W X H)

Q-value Q>40 10<Q<40 4<Q<10 1<Q<4 Q<1 Support Type I-V.Good II-Good III - Fair IV-

Poor V – V.Poor

Crown Support Bolt length 3 m 3 m 3 m 4 m 5 m Shotcrete thickness 50 mm 50 mm 50 mm 75 mm 100 mm

Bolt spacing SB SB 2 m 1.75 m 1.5 m Sidewall Support Bolt length 3 m 3 m 3 m 3 m 5 m Shotcrete thickness NR** NR** 50 mm 75 mm 100 mm

Bolt spacing SB* SB* 2 m 1.75 m 1.5 m * Spot Bolting **Not Required



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Table 2.21 Typical rock support for Shafts (6m x 12m) and Pump pits

Shafts and Pump Pits 6 X 12 m (W X B) Q-value Q>40 10<Q<40 4<Q<10 1<Q<4 Q<1 Support Type I-V. Good II-Good III - Fair IV- Poor V -V.PoorSidewall Support Bolt length 3 m 3 m 3 m 3 m 4 m Shotcrete thickness 50 mm 50 mm 50 mm 75 mm 100 mm

Bolt spacing SB* 2.5 m 2.0 m 1.75 m 1.5 m

* Spot Bolting Table 2.22 Typical rock support for Shafts (4m x 4m) and Pump pits

* Spot Bolting

2.6.4 Verification During Construction:

Tunnel design is fraught with uncertainty and therefore a risk assessment must be completed during design to evaluate the uncertainty and how to deal it with during construction. It involves detailed geological mapping and monitoring during the construction. During and after excavation some critical location which exhibited a particular geometric arrangement of joints and faults such that they were deemed as having potential of wedge sliding should be identified and the stability of cavern are further checked. For each of the identified location, a further joint set analysis should be undertaken based on the joint information from the excavation.

Shafts and Pump Pits 4 X 4 m (W X B) and 5 X 5 m (W X B) Q-value Q>40 10<Q<40 4<Q<10 1<Q<4 Q<1 Support Type I-V. Good II-Good III - Fair IV- Poor V-V.Poor Sidewall Support Bolt length 2.5 m 2.5 m 2.5 m 2.5 m 2.5 m Shotcrete thickness 50 mm 50 mm 50 mm 50 mm 100 mm

Bolt spacing SB* SB* SB* 1.75 m 1.5 m



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Discussion

In caverns excavated in jointed rock masses at relatively shallow depth, the most common types of failure are those involving wedges falling from the roof or sliding out of the sidewalls of the openings. These wedges are formed by intersecting structural features, such as bedding planes and joints, which separate the rock mass into discrete but interlocked pieces. When a free face is created by the excavation of the opening, the restraint from the surrounding rock is removed. One or more of these wedges can fall or slide from the surface if the bounding planes are continuous or rock bridges along the discontinuities are broken. Unless steps are taken to support these loose wedges, the stability of the back and walls of the opening may deteriorate rapidly. Each wedge, which is allowed to fall or slide, will cause a reduction in the restraint and the interlocking of the rock mass and this, in turn, will allow other wedges to fall. This failure process will continue until natural arching in the rock mass prevents further unravelling or until the opening is full of fallen material. Potential wedges and wedge support can only be determined during actual excavation. Minor wedges, sliding and toppling, will be formed but are supported by the typical rock support or in extraordinary cases by rock anchors as determined necessary. Provision must be made for the use of rock anchors, should large wedges be encountered.

The Cavern roof shall be provided with a systematic rock support irrespective of the rock class. A safe and robust design of the cavern roof is required to ensure no damage to the cavern facilities can occur due to roof instability. Critical areas such as shaft intersection with cavern, cavern ends, cavern end wall at pump-pit and cross tunnels intersecting caverns will require special design considerations in view of complex geometry and safety of cavern equipments. The excavation of the shaft will encounter poor weathered rock conditions until reaching down to fresh rock



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Appendix 1 Unwedge Analysis Information Document Name File Name: Wedge analysis Project Settings Project Title: Stability Analysis of Wedges for Underground Excavations Wedges Computed: Perimeter Wedges Units: Metric, stress as MPa General Input Data Tunnel Axis Orientation: Trend: 70° Plunge: 0° Design Factor of Safety: 1.500 Unit Weight of Rock: 0.027 MN/m3 Unit Weight of Water: 0.010 MN/m3 Seismic Forces Not Used Scale Wedges Settings Lower Left wedge [3] Scale Joint 1 (85/100) Persistence: 10.00 m Scale Joint 2 (85/020) Persistence: 10.00 m Scale Joint 4 (15/150) Persistence: 10.00 m Scale Out Of Plane Length: 10.00 m Roof wedge [4] Scale Joint 1 (85/100) Persistence: 10.00 m Scale Joint 2 (85/020) Persistence: 10.00 m Scale Joint 4 (15/150) Persistence: 10.00 m Scale Out Of Plane Length: 10.00 m Floor wedge [5] Scale Joint 1 (85/100) Persistence: 10.00 m Scale Joint 2 (85/020) Persistence: 10.00 m Scale Joint 4 (15/150) Persistence: 10.00 m Scale Out Of Plane Length: 10.00 m



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Upper Right wedge [6] Scale Joint 1 (85/100) Persistence: 10.00 m Scale Joint 2 (85/020) Persistence: 10.00 m Scale Joint 4 (15/150) Persistence: 10.00 m Scale Out Of Plane Length: 10.00 m Joint Orientations Joint 1 Dip: 85° Dip Direction: 100° Joint 2 Dip: 85° Dip Direction: 020° Joint 3 Dip: 15° Dip Direction: 150° Joint Properties Joint Properties 1 Water Pressure Constant: 0 MPa Waviness: 0° Shear Strength Model: Mohr-Coulomb Phi: 45° Cohesion: 0 MPa Tensile Strength: 0 MPa Bolt Properties Bolt Property 1 Bolt Type: Grouted Dowel Tensile Capacity: 0.196 MN Plate Capacity: 0.196 MN Bond Strength: 0.0707 MN/m Bond Length: 100% of Bolt Length Shear Strength: Used Shear Strength: 0.118 MN Bolt Orientation Efficiency: Used Method: Cosine Tension/Shear Shotcrete Properties Shotcrete Property 1 Shear Strength: 1.00 MPa Unit Weight: 0.026 MN/m3 Thickness: 10.00 cm



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Support Summary Summary of Perimeter Shotcrete No Shotcrete on Perimeter Summary of Perimeter Support Pressure No Support Pressure on Perimeter Summary of Perimeter Bolt Patterns Number of Bolt Patterns on Perimeter: 1 Perimeter Bolt Pattern: 1 Property: Bolt Property 1 Strength type: Grouted Dowel Bolt Length: 5.00 m Orientation: normal to boundary Pattern Spacing - In Plane: 1.50 m Pattern Spacing - Out of Plane: 1.50 m Pattern Spacing - Out of Plane Offset: 0.00 m Summary of End Bolt Patterns No Bolt Pattern on Ends Summary of End Support Pressure No Support Pressure on Ends Summary of End Shotcrete No Shotcrete on Ends Wedge Information Lower Left wedge [3] Factor of Safety: 291.260 Wedge Volume: 0.112 m3 Wedge Weight: 0.003 MN Excavation Face Area: 1.72 m2 Apex Height: 0.20 m Joint Trace Lengths: 1) 9.94 m, 2) 10.00 m, 4) 0.35 m Roof wedge [4] Factor of Safety: 1.918 Wedge Volume: 51.527 m3 Wedge Weight: 1.391 MN Excavation Face Area: 37.63 m2 Apex Height: 4.41 m Joint Trace Lengths: 1) 10.06 m, 2) 10.25 m, 4) 10.00 m



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Floor wedge [5] Factor of Safety: stable Wedge Volume: 15.857 m3 Wedge Weight: 0.428 MN Excavation Face Area: 29.79 m2 Apex Height: 1.60 m Joint Trace Lengths: 1) 7.78 m, 2) 7.78 m, 4) 10.00 m Upper Right wedge [6] Factor of Safety: 5.135 Wedge Volume: 13.906 m3 Wedge Weight: 0.375 MN Excavation Face Area: 23.54 m2 Apex Height: 2.04 m Joint Trace Lengths: 1) 6.58 m, 2) 10.17 m, 4) 8.42 m



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3 PROCESS DESIGN

3.0 General

For the performance of storage facilities, including loading and unloading of stored product, inventory management etc. the following above ground installations are envisaged:

a. Cavern Shaft Tops b. Heat Exchangers c. Metering Skids d. Booster Pumps e. Boiler f. Pipe way above ground g. Buried Pipelines and Electrical Cables h. Effluent Treatment Plant i. Fire Water Tank j. Fire Water Pump House k. Fire Station l. Control Room m. Standby Power Generator n. Outdoor Switch Yard o. Sub Station Building p. Compressed Air System q. Nitrogen Plant r. Maintenance Workshop s. Diesel Oil Tanks and Pumping System t. LPG Mounded Storage and Pumping u. Storm water reservoir v. Raw water tanks and pumps w. Drinking water sump and pumps x. Flare

The above mentioned facilities are located to meet the statutory requirements and best engineering practices adopted in Oil and Gas Industry. The overall plot-plan (Drawing No. A197-000-1647-0003) is annexed to the report.

The raw water for the proposed project is assumed to be available locally. The storm water is planned to be collected in a pond to utilize the water and reduce the requirement of river water/local sourcing.



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3.1 Storage Capacity and Storage Philosophy

The Padur crude oil storage cavern shall be designed as “U” shaped tunnels with a “D” shaped cross section. Each storage Unit will comprise of two cavern legs.

The total stored capacity of the proposed rock caverns facility is 2.5 MMT in four separate units, each unit having a net capacity of 0.625MMT.One unit shall be used to store Arabian light crude (low sulphur) and three units shall be used for storage of Arabian heavy crude. (high sulphur).

3.2 Storage Principle

The design of the storage is based on the hydraulic containment principle: the hydrostatic pressure at cavern depth has to be sufficient to counterbalance the cavern pressure and confine the stored product in the cavern. The storage facility at Padur will be based on this principle of underground storage with confinement by external groundwater pressure. The storage of crude oil in unlined rock caverns is based on the following basic principles: • The storage oil is lighter than water and basically not soluble in water. • The storage cavern shall be located below the surrounding ground water level. As the storage caverns are located below the surrounding ground water level, the oil is confined in the cavity. Due to natural fissures in the rock, water continuously percolates towards in the cavern, thus preventing oil from leaking out. Water leaking into the cavern (“seepage water”) is drained to a pump pit located in the deep end of the storage units, and automatically pumped out from the storage.

3.3 Storage pressure

The storage is designed to operate at following vapor pressure conditions: Operating Pressure Relief Valve 1.5 Kg/cm2g Maximum Operating Vapor Pressure 1.3 Kg/cm2g Minimum Operating Vapor Pressure 0.1 Kg/cm2g A pressure above atmospheric pressure is always maintained in the cavern, to eliminate leakages of air into the cavern, and any leakages of vapor out of the cavern can also be detected above ground. The cavern shall resist under pressure and is also designed for, an accidental load case, an internal transient explosion of 1MPa (10 bar (g)).



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3.4 Normal Storage Temperature

The normal storage temperature will be in the range +25° to +30° C. The temperature in the surrounding rock is approximately +28° C, which will be the crude temperature during long term storage without any additional heating. By allowing a span of normal storage temperature, the need for heating the storage under normal conditions is reduced to a minimum and can be performed intermittent, if necessary. As intake of crude into the cavern is at a temperature close to the storage temperature, the risk for thermal stratification is minimized. Seepage water into the cavern will be at a temperature close to the storage temperature, therefore thermal loss from this storage during normal storage conditions is thus brought to zero.

3.5 Crude Receiving System

Crude oil for storage will be received through 1,40,000 to 3,20,000 DWT ship tankers at a proposed new SPM to be installed off Padur. The ship tanker pumps will transfer the crude oil to the cavern site through a new subsea-pipeline from SPM through booster station near LFP and onshore pipeline, thereafter upto cavern. The process flow diagrams are presented herewith (Drawing No. A197-04-41-002-0101& 0102).The required battery limit pressure at the cavern facility before metering is 6.5 kg/cm2 (g). The maximum flow rate for cavern filling will be 10,000 m³/h.

3.6 Crude Oil Quality/Design Data

The facility will be designed to store two types of crude oil. A set of six units are allotted to store Arabian heavy crude oil and second set of two units, to handle Arabian light crude. However all the cavern units shall be designed to handle both the types of crude. The properties of crude oil considered for this project are mentioned in the table below.

Property Arabian Heavy

Arabian Light

Gravity °API 27 34.2 Sp. Gravity 60°F/60°F 0.8927 0.854 Reid Vapour Pressure Psi 7.0 3.5 Sulphur Wt% 3.0 1.65 Mercaptan Sulphur Ppm - 103 Wax Ppm - - Pour Point °C -18 (-54)-(-30)



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Viscosity Kinematic

@ 20°C Cst @ 40°C Cst @ 50°C Cst

43.3 18.4 13.0

11.6 8.04 6.83

The crude quality mainly affects the following major parameters: • Treatment requirement for seepage water. • Venting Requirement / Flaring. • Sludge and Wax formation. • Storage Temperature. • Stratification. • Pump Specifications

3.7 Crude Oil Pumps

The product will be pumped out from the cavern at a maximum flow rate of 10,000 m³/h and will be exported by the same pipeline used for inlet. With help of submersible pumps, crude oil is pumped to grade level. (+30m, m.s.l ). The submersible pumps shall be capable of handling melted waxes and crude sludge during dewaxing operation. Type of Pumps : Vertical Submersible Crude oil No. of Pumps : 4(3W+1S) per unit ×4 units = 16 Capacity : 1600 m3/hr (each pump) Head (m) : 165

For max crude transfer to SPM, two units are considered in operation simultaneously. After flow measurement, the crude oil is sent to the mainline pumps before being discharged at a maximum flow rate of 10,000 m3/h into the new pipeline which is used for both import/export operation. Type of Pumps : Horizontal Centrifugal (Mainline pumps at Cavern) No. of Pumps : 4(3W+1S) Capacity : 3300 m3/hr (each) Head(m) : 210



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3.8 Flow Metering Station

It is planned to install four no. of flow meters in parallel (3W+1S) to measure the maximum 10,000 m³/h flow rate into and out of the caverns(each meter capable of measuring 3300m3/hr). They will be equipped with strainers with air eliminators, as well as an integrated on-line automatic sampling skid allowing product samples to be taken for off-line laboratory analysis. A master meter in the form of Turbine flow meter shall be considered for verifying the ultrasonic flow meters. The capacity of the turbine meter will be 3300m3/hr.

3.9 Casing pipes

All pumps, level and temperature transducers and steam lines for the caverns shall be installed in casing pipes. The casing shall be designed to withstand an explosion, inside the cavern up to a pressure level of 1 MPa (explosion in the vapor phase). During normal operation the pressure inside the casing pipes shall be equalized to the cavern vapor pressure by pipe connections at the cavern shaft top.

3.10 Boiler

3.10.1 General Data Boiler/Heat Exchanger

Steam generation is required for : • Heating crude during dewaxing/desludging

• Steam injection to pump pits for improving fluidity.

Steam shall be made available at vendor's battery limit at minimum header conditions (t = 67 deg c & pr = 6.5 kg/cm2g). The total boiler load is 30 TPH of steam. The boiler typically consists of: • Two boiler units(12 TPH each), de-aereator, feed water treatment and

softening plant(to meet the desired BFW specification) , pumps, valves, fuel burner and control unit etc. The assembly shall be packaged type.

• Two furnace fuel oil atmospheric tanks (Commercial grade Diesel) of capacity 500 m3 each.



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3.10.2 Crude Oil Heating Philosophy

• Crude oil heating is performed to enable bottom 15% of the crude to be heated up in order to melt the sludge/wax formed, and to decrease the product viscosity for making pumping easier.

• One month time considered for entire heating operation. • It is envisaged that one unit out of four will be undertaken for desludging

operation at a time. • A total of two heat exchangers, each of capacity 800 m3/hr are proposed to

facilitate the heating of crude from one unit. • Heat exchanger shall be of tube/shell type. • Inlet temperature shall be varying between 28 °C to 60 °C. • Outlet temperature and maximum allowable pressure drop should not exceed

70 °C & 1 bar respectively.

3.10.3 Heating by steam Injection

Local heating of the water in the pump pit can be achieved by direct injection of steam into the water. It is considered that 6 kg/cm2g pressure steam at cavern top is adequate for heating. Steam shall be injected @ 4-5 tons /hr. Injection at the bottom of the pump pit also creates turbulence and mixing of sludge into the water. Steam injection nozzles can also be used for injection of additives to minimize bacterial growth in the oil / water interface.

3.10.4 Steam Injection to Flare

Provision for steam injection to flare tip for smokeless flame has been considered. The steam capacity for smokeless flaring shall be for hydrocarbon vapour load equivalent to 20% of peak load. It is estimated that around 0.64 tons/hr is required for this operation.

3.11 Cooling Water System

Cooling water is required for cooling of air compressors and pumps. A cooling tower of capacity 150 M3/hr (tentative) has been considered for the proposed storage facility.

3.12 Nitrogen

Nitrogen is required for the underground storage crude oil to perform the following activities: • Removal of O2 from the cavern prior to taking crude oil to the cavern.O2

content should be brought down below 5%.



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• Maintaining cavern pressure while pumping out crude from the cavern. Pressure to be maintained at 0.3 kg/cm2g.

• Any maintenance activities in the pump shaft. • Quicker dispersion of hydrocarbons and other gases released through vent.

3.12.1 Nitrogen Requirement during Commissioning/Normal Operation

The Nitrogen requirement during commissioning shall be met by using IG generators. During normal operation, maximum nitrogen requirement will be at the time of crude pump out @ 10,000 m3/hr (max transfer from two units). The quantity of N2 necessary to meet this requirement is computed as 12000 Nm3/hr.

3.12.2 Nitrogen System

As the vapor pressure of the stored crude oil is below atmospheric pressure, it is necessary to inert the vapor phase with Nitrogen. Moreover, Nitrogen is also required when the cavern pressure drops with crude oil withdrawal. In order to meet the requirement of 12000 Nm3/hr during withdrawal, two PSA Inert gas generator skids each of capacity 6000Nm3/hr are proposed. The quantity and quality of air needed for inert gas generation shall be met by dedicated compressors, dryers etc., which are considered as part of nitrogen package vendor.

3.13 Compressed Air System

Compressed air is required in the complex for the following main requirements: • As Instrument Air to operate the various instruments in the facility and also

for the purging of some control panels • As Process Air (for example as aeration air for ETP). • As Service Air for operating hose stations for various miscellaneous uses in

the complex, including providing breathing air to personnel during vessel entry, etc.

Compressed air required for all of the above uses, is generated at a centralized location in the topside of cavern and distributed to the various users through headers. Two qualities of compressed air shall be produced and distributed: • Plant Air comprising compressed air cooled to ambient temperature. This air,

though not containing any entrained water droplets, is saturated with water vapor at the supply conditions.



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• Instrument Air comprises compressed air cooled to ambient temperature and dried to remove water vapor to meet stringent atmospheric dew point requirements.

During a power failure, to enable the safe shutdown of the unit and other users in the complex, facilities will be provided to supply emergency instrument air for upto 30 minutes by providing a storage vessel. The capacity of Compressed air unit is 225 Nm3/hr and air shall be available at Battery limit of compressed air system at the following conditions. • Maximum pressure of 8.0 kg/cm2 (g) , • Normal pressure of 6.5 kg/cm2(g) and • Minimum pressure of 5 kg/cm2 (g)

3.14 Seepage Water System

It is estimated that a seepage water flows into the cavern @ 60m3/hr. The seepage water is removed from caverns by submersible pumps installed in Duples SS 25Cr casings anchored in the concrete plug at cavern roof depth extending down into the cavern sump. The casing bottom ends in the cavern water phase, ensuring that the pumps always pump seepage water only. Type of Pumps : Vertical Submersible Seepage Water Pumps No. of Pumps : 2(1W+1S) per unit ×4 units = 8 Capacity : 60 m3/hr (each) Head (m) : 141

3.15 Seepage Water Treatment

Seepage water shall be pumped to the water treatment plant from seepage water tank using ETP feed water pumps. Water treatment plant (ETP) of capacity 60 m3/hr (H) shall be designed in such a way, so as to meet the quality of water for reuse in • Make up fire water tank. • Supplementary make up water to the water curtain. • Irrigation purpose in green field area.

This is to achieve zero discharge for this facility.



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3.16 Flare System

It is planned that flaring of gas and vapor will be required during filling, during circulation and during heating. PSVs is provided to release the vapor to flare in case of uncontrolled pressurization during last stage of filling. The flare system and the PSVs is designed for the flare load corresponding to maximum crude inlet capacity, i.e. 10,000 m3/h. Height of the flare stack shall be decided based on ground level radiation as per API 521. One LPG mounded bullet of capacity (20m3) is required for pilot ignition for flare system. In view of the possible commercial operation of the phase II storage facility; the possibility of having Zero Flaring Concept was also evaluated. However, it is felt that the concept could be considered for adoption during the FEED stage once the operation philosophy is finalized. 3.17 Elevation Inline booster pumping area FGL elevation : +4.6 m above MSL Low / Mean / High Sea water level : 0.03/0.95/1.68 m above CD FGL of cavern storage area : +30 m above MSL FGL of mainline pump area at Cavern : +30 m above MSL Ship Tanker Rail elevation : 11.6 M above chart datum 3.18 Integration with Phase I Storage Facility During the present DPR stage, an attempt was made to study possible sharing of facilities between the existing Phase I storage facility and the planned Phase II storage facility. However, owing to non availability of any specific operation philosophy for the Phase II storage program, both Phase I and Phase II storage facilities have been designed as stand-alone units with inter connectivity through pipeline.



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4 INTEGRATION WITH EXISTING FACILITIES

4.0 General

The storage facility shall be integrated with a captive offshore oil terminal (SPM) which could be located off the coast of Kaup, at about 5.0 Kms. from the proposed site. This would require the additional pipeline requirement connecting the storage facility to the new offshore oil terminal (SPM) Following assumptions have been made in conceptualization of the schemes for integration to existing facilities: a) Maximum utilization of existing facilities to minimize cost towards creating

new facilities.

b) Existing facilities would be available for filling in the strategic storage (s) and rotation of stored crude at pre-determined intervals so as to keep the facilities in working condition.

c) During emergency scenarios existing facilities would be available full time for transportation of the stored crude oil.

d) Infrastructural facilities required for the storage sites shall be drawn from the existing facilities of oil companies, wherever possible.

e) Crude oil hold up in the existing pipelines has not been considered as part of the storage inventory.

Details of the envisaged integration to the existing facilities are enumerated herewith. 4.1 Pipe Line Integration

The envisaged storage facility at Padur involves underground rock cavern storage of 2.5 MMT capacity. The facility involves development of underground unlined rock cavern for storage of crude oil and shall be integrated with a new dedicated pipeline connecting the facility to new SPM located off Kaup. The complete facility shall comprise of: • Single Point Mooring System (SPM) • Pipeline End Manifold (PLEM) with temporary Pig Launcher



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• 48” OD x 18 km Long offshore pipeline • Inline Booster Station • 42” OD x 5 km Long Onshore Pipeline

The design, fabrication, installation, testing and commissioning of pipeline shall meet the requirements of ASME B31.4 “Pipeline Transportation Systems for Liquid Hydrocarbons and Other Liquids”. Additional the requirements of OISD 141 “Design and Construction requirements for cross country hydrocarbon pipelines” shall also be met. 4.2 Pipeline Designation: (a) Offshore Section

Origination : PLEM Termination : LFP Pipeline Length (Km) : 18 km Pipeline OD (mm) : 1219 mm Pipeline Material : API 5L Gr X-65 (CS), LSAW/HSAW Wall thickness, mm : 22.2 / 20.6 Service : Crude Oil Design Life : 30 years Design Pressure, kg/cm2 (g) : 19 Design Temperature, °C : 65 Hydrotest Pressure Kg/cm2 : 1.25 times the Design Pressure Corrosion Coating Material : Three Layer Polyethylene Thickness (mm) : 3.0 Piggability : Suitable for Intelligent Pigging

(b) Onshore Section

Origination : Inline Booster Station Termination : Underground Rock Cavern,Padur Pipeline Length (Km) : 5 km Pipeline OD (mm) : 1067 mm Pipeline Material : API 5L Gr X-60 (CS), LSAW/HSAW Wall thickness, mm : 11.1 Service : Crude Oil Design Life : 30 years Design Pressure, kg/cm2 (g) : 41 Design Temperature, °C : 75 Above Ground 65 Underground Hydrotest Pressure Kg/cm2 : 1.25 times the Design Pressure



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Corrosion Coating Material : Three Layer Polyethylene Thickness (mm) : 3.0 Piggability : Suitable for Intelligent Pigging

4.3 Pipeline Integration Route Map & Schematics:

Drawing No. A197-000-11-42-3008 Integration Pipeline Route Map

Drawing No. A197-000-11-42-3004 Schematic Arrangement for Integration Pipeline

4.4 Process Description

Crude Oil is imported through a proposed new captive SPM by a 48" diameter pipeline, approx.18 km upto inline booster pumps near LFP and a 5 Km long and 42” pipeline from booster station at LFP to storage cavern. For effective maintenance of pipeline, pigging facilities (for intelligent pigs) is provided for the crude oil pipeline from SPM to inline booster pumping station near LFP. Temporary pig launching facilities are envisaged at PLEM and permanent receiving one at inline booster pumping station. The crude intake and dispatch facility from cavern are considered with same pipeline and SPM. Crude shall be received at a maximum rate of 10,000 m3/hr from the new captive SPM. The details of the In-line Booster station will be as under: Capcity : 3300 me/hr (each) No. of Pumps : 4 (3 W +1 S) Type : Centrifugal



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5 FIRE PROTECTION FACILITIES

5.1 GENERAL

Large volumes of fuel confined in rock caverns are not exposed to fire, because of the absence of oxygen in the storage. The installations connecting the cavern with the surface are dimensioned to withstand an internal explosion. In the remote possibility of such an occurrence, the pressure is transferred through the cavern vapour line out to atmosphere via the flare stack. In case of fire, the oxygen in the cavern will be consumed and the fire will rapidly die by itself. The major risk of fire is encountered when a pipe at the surface is leaking. In case of ignition the propagation of fire shall be prevented by isolating the burning section while cooling the surrounding area with water spray. Trailers with a foam tank shall be used in combination with the hydrants and sprinklers. The fire prevention has been planned to be ensured by: • Suitable choice of equipment and installations withstanding fire and high

temperatures. • Safety distance between different areas and equipment. • Sectioning and isolating different hazard zones. • Effective spill / leakage detection system. • Effective fire, gas and smoke detection systems both at surface and inside

buildings. • Fire fighting system and extinguishing equipment always ready to use. The sprinkler systems has been planned to be installed at the following areas: • Shaft Top • Heat Exchanger • Metering Station • Booster Station Fire alarm is to be initiated by temperature, smoke and gas sensors.



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5.2 CODE AND STANDARDS

Special Requirements of the Indian Fire Authority shall be applied. OISD / NFPA / TAC standard shall be applied for the fire protection equipment particularly the following parts OISD STANDARDS • OISD Standard -117 (Fire Protection Facilities For Petroleum Depots,

Terminals, • OISD Standard -118 (layout for Oil and Gas Installation). • OISD Standard -163 (Process Control Room Safety) • OISD Standard -173 (Fire Prevention and Protection System for Electrical

Installations) • NFPA FIRE PREVENTION CODE • NFPA 10: Portable Fire Extinguishers • NFPA 12: Carbon Dioxide extinguishing systems • NFPA 13 Sprinkler systems • NFPA 14 Stand-by and Hose systems • NFPA 15 Water Spray systems • NFPA 17 Dry chemical extinguishing systems • NFPA 20 Centrifugal Fire Pumps • NFPA 22 Water tank for Private fire protection • NFPA - 2001 Clean Agent Extinguishing System. Tariff Advisory Committee (TAC) RULES Fire Protection Manual (Internal appliances, fire engines, trailer pumps, and hydrant systems) (By Tariff Advisory Committee). Rules of TAC for • Sprinkler System • Water Spray System

5.3 SOURCE OF FIRE WATER

Freshwater shall preferably be used as firewater source. In this study freshwater supply is assumed either from sub surface sources and / or from the nearby local area.



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Fire water shall be supplied to the fire storage tank via an external supply. The tank shall be connected to the water supply in such a way that it is automatically refilled as soon as the level of the water decreases (float ball valve). The firewater tank is calculated for an autonomy of 4 hours at maximum fire flow demand plus a water reserve for miscellaneous services and cleaning.The firewater tanks is to be constructed of carbon steel tanks and located above ground.

5.4 FIREWATER PUMP HOUSE

Firewater pump house shall be RCC frame construction having R.C.C. roof with brick walls as per TAC norms. It shall have provision for separate battery room. A HOT crane shall be provided for maintenance and erection. A local fire control panel in operator’s room shall be provided for all controls of firewater pumps.

The Fire Water Pumps will have following specifications:

• Main Pumps Capacity - 410cum/hr.(TAC approved) (2W+1S) • Head 8.8 kg/cm2g min. • Type Horizontal • Standby pumps Capacity - 410 cum/hr & Head-8.8 kg/cm2g • Drive Electrical (main pump) / diesel engine (stand by) as per OISD. • Power supply to Electrical driven pumps To meet the requirement of the

OISD. • Diesel Driven Pumps To meet the requirement of OISD • Diesel - day tanks capacity – Minimum 12 Hour running storage • Mode of Operation Starting of pumps Automatic through pressure switches

and manual stopping of pumps • Fire water Jockey Pumps

a) Capacity 2 nos. (Capacity - 50 m3/hr) b) Head To keep the system pressurized at 8.8kg/cm2 continuously c) Type Horizontal d) Drive Electric To run on emergency power as well. e) Mode of operation Automatic through pressure switches with provision

to start and stop manually.

5.5 FIREWATER DISTRIBUTION TO HYDRANTS / MONITORS

The firewater distribution network shall be constructed using a closed loop arrangement around the surface area, this will enable a supply of firewater upto the full capacity and pressure to any emergency area even when a section of the network is broken or out of service.



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Pneumatic motor operated valves and hand operated butterfly valves are installed throughout the system. Operated valves shall be fail-safe type and shall automatically open in case of emergency (ESD). The fire fighting distribution network shall be buried.

5.5.1 Fire Water Network

a) Location of Hydrants & Monitors • Hydrants shall be provided @ 45m c/c around utilities • Hydrant & water cum foam monitors shall be provided 30m c/c around

tankages • Hydrants & Monitors shall be placed near the facility for proper coverage

as per TAC guidelines b) Isolation valves

• Isolation valves shall be provided at crossings (Junctions) to ensure easy maintenance and uninterrupted water supply in case of break down.

• Isolation valve shall be provided below monitor and at all hydrants. • Isolation valve shall be provided at all tapping points on firewater headers. • Landing valves on buildings shall have individual isolation valve at each

tapping. • Only carbon steel Gate valves shall be used. No cast iron valves shall be

used. c) Hydrants

• Hydrant shall be BIS approved, • Outlet : 63mm double headed • Pipe size: 4" CS • Capacity: 36 cum/hr

d) Monitors • Monitor shall be BIS approved

i. Pipe size : 6" CS ii. Capacity : 144 cum/hr

• Water cum Foam Monitors shall be BIS approved i. Pipe size : 8" CS ii. Capacity : 2580lpm

e) Hose Reels & Hose boxes • Hose reel shall be 40m long of 20mm bore size. • Hose boxes shall be at every alternate hydrant points & landing valves. • Hoses shall be as per BIS kept in each hose cabinet.

f) Landing Valve • Double headed, to be provided on landings of first floor and above.



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5.5.2 Water Spray System

Rate of Water Application & Mode of Operation of Water Spray System

Facilities Mode of Operation Rate of application

Mounded Bullet Automatic 10.2 lpm/sqm Metering station Manual 10.2 lpm/sqm Shaft top Manual 10.2 lpm/sqm Heat exchangers Manual 10.2 lpm/sqm On pumps(Booster) Manual 20.4 lpm/sqm Transformers Auto (Deluge system) 12.5 lpm/sqm Diesel Storage Tank Manual 3.0 lpm/sqm

5.6 MOBILE FOAM EQUIPMENT

One trailer with a tank containing foam liquid shall be provided for the plant. Mixing equipment, foam generators, hoses and nozzles to use in combination with hydrants shall be stored in the site warehouse. The capacity of the tank shall be sufficient to cover an area of 150 m2 at hydrant flow rate (approximately 1000 litres depending on the foam number).

5.7 FIRE PROTECTION OF ELECTRICAL AND CONTROL ROOMS

Electrical and control rooms shall be protected with a fixed inert gas injection system type Inergen. Cylinders shall be stored outside the building.Each room shall have several types of detectors, optical and ionic. The inert gas injection shall only be automatically activated on alarm from two detectors. A delay of a few minutes will permit the operators to evacuate the building. Emergency signals such as red beacon lights and sirens shall be installed.

5.8 PORTABLE EXTINGUISHERS

At the surface each installation and equipment zone shall have two 9 kg portable extinguishers. Wheeled 50 kg powder extinguisher shall be provided for the diesel storage tank area. Each room of the site building shall be equipped with 2 portable powder extinguisher.



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6 INSTRUMENTATION AND CONTROL SYSTEMS

6.1. GENERAL

The purpose of this section is to describe the main above ground systems used for monitoring all relevant information of the storage, for ensuring the safety of the facility and for performing the process control of the plant.

6.1.1 Control Room Concept

The entire Strategic Storage unit including its all utilities is envisaged to be operated from Main Control Room which will have rack room, engineering room, Console Room for housing DCS, PLC as well as CCTV components. Main Control shall provide total plant information to the plant operators and plant managers simultaneously at one location.

6.1.2 Control System

The overall system configuration diagram showing the major hardware for DCS, PLC & other sub-systems shall be conceptualized during engineering phase of the project. The major features for the Project control system are as follows: The control & monitoring of process unit & Utility Areas shall be through DCS system, with Foundation Field Bus (Field Barrier concept) based field instruments for the open and closed loops (except complex loops) and Smart field instruments shall be considered for the DCS complex loops, Special fast acting loops, Safety & Emergency Shutdown related field instruments. In general, all interlock and shutdown of main process units shall be executed through ESD PLC. The PLC shall be SIL-3 TUV certified. PLC shall be either Triple Modular redundant or Quadruple Modular Redundant. Utilities packages like ETP plant, Instrument Air compressor, Utility Boiler, Nitrogen package etc shall have their dedicated Non-SIL dual redundant PLC for interlock & shutdown as well as control & monitoring with serial interface to main plant DCS for centralized monitoring.



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The Major control systems are:

a) Distributed Control System (DCS), b) Emergency Shut Down system (ESD), c) Fire system, d) Gas detection system, e) Access and Intruder alarm systems, f) Video surveillance system.

6.2. DISTRIBUTED CONTROL SYSTEM (DCS)

The Distributed Control System shall be able to:

a) Control all the storage equipment (pumps, valves, etc.,) b) Monitor all the storage data, c) Archive data, d) Alarm / inform the operating staff (using graphic displays notably), e) Communicate with others systems (such as Programmable Logical

Controller). Concerning the process control, it shall be performed using Process and Instrumentation Diagram’s, logic diagrams, process descriptions. This system shall be designed by taking into account the following aspects:

• Reliability, • Availability, • Maintainability.

A HVAC system shall be foreseen in the control room and the technical rooms.

6.2.1 Electrical Power Supply

The DCS shall be powered by two different electrical sources:

• 230 VAC 50 Hz from normal power supply, • 230 VAC 50 Hz from UPS.

The DCS shall supply, by internal means, the levels of voltage required for its different modules.



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6.2.2 Human / Machine Interface (HMI)

The following equipment shall be located in the control room for operating staff: a) 3 operator stations including 21" colour graphic screen, operator keyboard

with special function keys, standard keyboard, trackball (or mouse), disc drive, CD-ROM drive

b) One laser printer for alarm report and process status event report c) One colour graphic laser printer or video copier for hard copy d) One configuration station (that can be used as operator station, if necessary. The operator stations shall consolidate all information, display data and enable operators to initiate and stop sequences/programs, adjust controller set-points, transfer from one mode to another (manual, automatic,.. to be defined with the customer), start and stop motors, open and close valves…

6.2.3 Access Levels

The system shall allow three levels of access (as a minimum): a) Operator access: this level shall authorize the normal control room operator

functions (Automatic /Manual command, set point change, alarm, acknowledgement, etc.)

b) Maintenance access: this level aims at testing equipment, and / or modifying software parameters which are not accessible to the operator (some PID's action, timer setting, maintenance, inhibit). It shall also provide access to all the operator displays.

c) Engineer access: this level aims at providing system network maintenance functions and developing / testing software configuration. It shall also include all operator and maintenance functions.

These accesses shall be secured using key-lock and / or passwords.

6.2.4 Graphic Displays

The operator stations shall be used to provide the operator with quick and easy access to the storage information and controls. It shall be possible for the operator to move between displays using "touch targets". The stations shall also be used to provide the operator with information and control facilities of ESD and F&G systems connected to the DCS on customized displays built within the DCS.



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All monitored measured variables shall appear at least once on a standard display. As a minimum, the following graphic displays shall be realized:

a) Storage overview display representing the major components of the storage display,

b) Unit graphic display / Process operating displays to supervise and control the unit / sequences from the display,

c) ESD / Safety displays dedicated to safety data / functions, d) Trend displays, e) Historical displays, f) Loop displays for tuning (usually standard function such as faceplate), g) System Status display (usually standard function), h) Alarms display.

6.2.5 Engineering/Configuration station

A separate configuration station shall be considered. This PC shall be proposed with a dedicated programming software. For configuration, it shall be possible to use ladder logic or high language complying with IEC 61131 standard. The software shall ensure:

a) On line modifications without any process disturbance, b) Generation of soft documentation, c) Override of safety input for maintenance.

Access to soft modification shall be restrained by password.

6.2.6 Unit History Node (UHN)

Unit History Node (UHN) shall be provided to store automatically gathered data from control systems i.e. DCS & PLC, manually entered data, for long term historisation, to carry out calculation, to present the data in a meaningful manner for performance enhancement and fault analysis and for interface to higher level plant wide network through firewall.

6.2.7 Alarm Information Management System

Alarm Information Management System shall be provided for the project to have centralized alarm information which can be used for acquiring, sorting, add value and to provide redistribution platform so as to streamline and transform raw alarm data into intelligent, add actionable information for plant operation personnel.



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6.2.8 Documentation Node (DON)

Documentation Node (DON) shall be considered to store complete unit documentation and shall be connected to system on plant wide information network (TCP/IP network).

6.2.9 Communication

The DCS network manages all the exchanges of data between components of DCS. The data communication system shall be fully redundant and all access ports shall be redundant. The data shall be transmitted with a high degree of reliability and sufficiently high speed to comply with the specified performances. The transmission protocols shall be designed open and compatible with all bus participants and shall have proven reliability and efficiency by significant industrial use. Preferably, an optical bus suitable for industrial use and based upon Ethernet (IEEE 802.3 standard) shall be used. The rate of communication shall not be less than 1 Mbit /sec. The DCS shall be connected to various sub-systems from different Vendors through redundant or non redundant gateway and data links to allow data acquisition and supervisory control from the operator stations. All data links shall provide secure transmission with data transfer error detection, self diagnosis and retry facilities. Detected errors and faults shall initiate an alarm and stop data communications. Redundancy shall enable data communications to continue using the healthy link. Links shall be provided with galvanic/optical isolation. As far as possible, serial links shall be implemented with Modbus protocol.



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6.2.10. Preliminary Inputs / Outputs Take-off

The estimated number of inputs and outputs for the DCS is tabulated below:

Digital Input :DI Digital Output :DO Analog Input :AI Analog Output :AO

1100 500 300 70

6.3. EMERGENCY SHUTDOWN SYSTEM (ESD)

The Emergency Shutdown system shall be designed to bring the installation to safe status independently from the main control system (DCS) should any critical safety condition occurs. The usual architecture for ESD system shall consist in:

a) one or several fail safe controllers dedicated to safety, b) one failsafe redundant bus, c) one configuration station.

The ESD system shall be configured using PID’s, logic diagrams.

6.3.1 Electrical power supply

The ESD system shall be powered by two different electrical sources:

a) 230 VAC 50 Hz from normal power supply, b) 230 VAC 50 Hz from UPS.

The ESD system shall supply, by internal means, the level of voltages required for its different modules. Each ESD PLC shall have a redundant power supply module with a dedicated protection system to ensure the reliability and availability of the supplied voltage. The changeover from one source to another shall not disturb the system.

6.3.2 Human / Machine Interface (HMI)

Three identical operator stations shall be supplied to allow the operator to supervise and control the storage facilities.



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These stations shall be the same for ESD and DCS systems. The graphics displays are described under DCS graphic displays description.

6.3.3 Engineering / Configuration station

A separate configuration station shall be supplied (separate from the one used for DCS). This PC shall be proposed with dedicated software. This software shall comply with IEC 61131 standard. Like for the DCS, the software shall ensure:

a) On line modifications, b) Generation of soft documentation, c) Override of safety input for maintenance.

6.3.4. Preliminary inputs / outputs take-off

The estimated number of inputs and outputs concerning the safety system is the following:

Digital Input :DI Digital Output :DO Analog Input :AI Analog Output :AO

100 200 30 20

6.4. FIRE AND GAS DETECTION SYSTEMS

The Fire and Gas (F&G) systems consist of:

a) Fire and gas detectors. b) Fire and gas protection systems. c) Dedicated fire and gas supervision system (if any).

Appropriate sensors shall be used in both cases. An individual alarm shall be available for each fire or gas detector. The Fire and Gas systems shall be configured to respond such that any incident shall initiate the following executive actions:

a) Shutdown of all rotating equipment (except seepage water pumps) b) Closing of all valves (except these of seepage water discharge line) c) Isolate the power supply d) Alert personnel on the plant (using audible and visual alarms).



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6.4.1. Electrical Power Supply

The electrical power supply is described under ESD and DCS electrical power supply.

6.4.2. Detectors

In order to control at any time, the presence of combustible vapours, gas detectors shall be installed throughout the installation in all areas where these vapours may propagate or accumulate. The gas detectors shall be installed at ground level, in the following areas: a) In process and utility areas, where equipments are susceptible to generate a

hazardous area, b) In buildings, at air intake and cable pulling chambers, c) Around electrical power transformers and utility areas in general.

The gas detectors shall be chosen in the following types: a) Catalytic oxidation for process facilities, power transformers, buildings, b) IR (Infra Red type) open path detector for perimetric protection. Fire detectors shall be installed in each fire area where a hazard of fire exists. The fire detectors shall be chosen in the following types: a) In process areas:

a. Flame detectors Ultra-Violet in conjunction with Infra-Red type (UV/ IR) b. Fusible Plugs (FP) detectors

b) In buildings:

a. Smoke detectors Ionization type (I) or optical (O) in false floor and ceiling, b. Heat detectors rate of rise type (TV) in false floor and ceiling, c. Flame detectors (UV/IR) in buildings that include rotating equipment, d. Heat detectors Thermostatic type (TS) in workshop and warehouse.

All the detectors must be certified for use in hazardous areas.



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6.4.3. Fire and Gas detection units

Outputs from the fire and gas system can be sent directly to equipment (electrical isolation, water deluge valve…) and / or be routed to the ESD system that shall take process-related actions (closing /opening safety valves). a. Gas detection unit The gas detection unit shall be a standard 19" modular rack systems, installed in a cubicle. The racks shall be equipped with modules data acquisition. These modules shall be selected so as to provide the following specifications: a) One fault contact (sensor failure, short circuit, ground fault, power failure) b) DEL shall be foreseen on each module to indicate the module status, c) Two adjustable alarm levels for each sensor (Thresholds to be defined) –

One "high level" for alarm (to DCS) and one "high high level" for emergency trip (to ESD or directly to equipment),

d) One analogue measurement for each sensor (connected to DCS for example).

A serial link shall be available on the detection racks (for connection to DCS). b. Fire detection unit Like for the gas detection system, the fire detection unit shall be a standard 19" racks. Each detection module shall be able to initiate alarms and / or special actions in case of fire detection. The system shall be connected to DCS (serial link) and to ESD (Hardwired links) and / or directly to equipment (firewater valves). In addition to this system, manual call points shall be foreseen.

6.4.4. Fire and Gas Hardware Panel

To complement the fire and gas detection units, a gas detection and fire fighting hardwired panel shall be foreseen.



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It shall display all main alarms, provide all necessary push-buttons for equipment control (firewater valves mainly, emergency water injection in shaft,) and also indicate the positions of main fire fighting equipment. The panel shall be designed per zones and per type of information in order to enable the operator to quickly and clearly identify the incident and its location. All these indicators and push-buttons will be hardwired directly on the equipments, independently of all automatic systems. This principle ensures a redundancy with the systems and with the vital equipment of the plant.

6.5 TANK FARM MANAGEMENT SYSTEMS (TFMS)

Tank Farm Management Systems (TFMS) shall be considered for the Cavern Storage Area with centralized Tank Farm Management PC located in Main control room. Tank Farm Management Systems (TFMS) shall be interfaced to the main Plant DCS system through serial links.

6.6 SURVEILLANCE SYSTEMS

The surveillance systems consist of: a) one intruder detection system, b) one access control system, c) one Closed Circuit Television (CCTV) system.

6.6.1 Intruder Detection System

The basic principle of this system is to ensure overall security for process areas and the specified buildings. The whole system should be based on digital fully programmable control unit (mounted in standard 19" cabinet). This unit shall be equipped with the required interfaces for cooperation with CCTV system and shall be equipped with devices providing selective monitoring and events recorder (PC and printer). The detectors shall be chosen in the following types: a) Infra-red Beam detectors (based on transmission of infra-red beam between

a transmitter and a receiver), b) Passive Infra-Red (PIR) detectors (based on temperature elevation), c) Microwave detectors (based on microwave movement detection), d) Dual technology detector (Microwave and Infra-red),….



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The detectors which cover the entry area(s) shall be interlocked with the access control system which controls the gates to disable automatically the protection of the relevant sector when a vehicle or a person enters the site. All sensors and contacts shall be connected as separate lines to the control unit.

6.6.2. Access control system

The system shall control and record the movements of persons throughout the area by assigning individual permission to each passage, using time zones to protect the passage, and controlling the time of staying inside the zone. The system shall log users’ permissions. Leaving the zone (opening the door from inside the zone) should be easy, that is, by pressing the door handle or button. The doors shall be equipped with automatic shutting devices. The system shall have a modular configuration and its ID card-based operation. This system shall be installed at entry / exit points (process areas, buildings). The system shall be able to record all the following events: a) Authorized entry, b) Authorized exit, c) Unauthorized entry attempt, d) System communication lost, e) System failure. The access control system shall be connected to CCTV system and all the data shall be transferred to a computer in the control room. The following devices shall be used:

a) Card readers, b) Magnetic door contacts, c) Electric door locks,…

The access control system and the intruder detection system can be combined in one system.

6.6.3 CCTV System

CCTV system shall be used for plant surveillance with cameras, Pan & Tilt unit, Washer & wiper in the field and control equipments like video encoder, network



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switch, video matrix NVR etc. in the SRR / Main Control Room. The CCTV monitors and their joysticks/keyboard shall be located in the console area along with the operator station. The conceptual overall configuration diagram showing the major hardware of CCTV systems shall be prepared during detail engineering stage The CCTV system, which shall be designed to provide general plant monitoring, shall include cameras, monitors, camera controllers and cables. All components and materials shall be of the latest field-proven design and in current production. The equipment shall be installed outdoors and shall be designed for both continuous operation and in periods of inactivity in an atmosphere made corrosive by traces of chemicals found in petrochemical plants. Environmental conditions also include the presence of rodents and insects. All electrical components shall be suitable for use in the environment specified. The available unfiltered industrial power is 230 VAC, single phase, 50 Hz for the monitor(s). The equipment shall be capable of proper operation for voltage deviations of ±10 % and frequency deviations of ±5 %. The CCTV system shall deliver a picture that is sharp, crisp and clear. The proposed cameras shall generate a video signal exhibiting low noise while delivering a high resolution display. The cameras shall be located at the following areas: a) Flare area, b) Booster/shelter area. c) Shaft Top Area. d) ETP area. e) Boiler Area. f) Main Gate g) Other Gates. A complete set of accessories normally used for operation, maintenance and testing shall be supplied. For example, the following accessories shall be supplied:



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a. Environmental enclosure with blower and sun shroud (for camera), b. mounting pole or tower, c. Camera video and control cables. The cameras shall be connected to monitors. At least, one 40” monitor shall be located in the control room and one in the guardhouse. A camera control console shall be provided with the items listed below: a) One console with switchover equipment for switching any camera to the

monitor, b) One PC loading picture permitting one-month storage period of recorded

pictures from each camera.



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7 ELECTRICAL INSTALLATION

7.0 GENERAL

Electrical power shall be received from State Electricity board through 110 kV, Single circuit transmission line (Double circuit towers), “Lynx” ACSR conductor up to 110 kV switchyard.

7.1 110 KV SWITCHYARD

110 kV, 630 A, 40 kA for 3 sec, Switchyard shall be complete with following major items: a) Power transformers, 20/25 MVA 110/6.6 kV ONAF with OLTC– 2 nos. b) Incomer – 1 nos. c) Outgoing bays- 2 nos. d) Outdoor metering Current Transformer, Potential Transformer e) Lightning Arrestor f) SF6 Circuit breaker – 3 nos. g) Numerical protection relays h) Control room with indoor 6.6 kV circuit breaker, i) Auxiliary switchboard, j) Battery & battery charger. Switchyard shall be provided with Over current, Earth fault, Bus bar feeder & transformer differential protection through numerical relay and shall be connected to Data concentrator in Sub-station. Power distribution for all the plant loads shall be from this Main electrical sub-station. Further, separate MCC rooms shall be provided for Fire water, ETP and Boiler areas fed from Main sub-station. Main Sub-station shall consist for following major equipments: a) 6.6 kV Switchgear – 1 no. with 2 nos. Incomers, Bus-coupler with Auto/

Manual changeover, Bus and Line PT, Vacuum circuit breakers, outgoing plant and motor feeders, numerical relays and Data concentrator with engineering and operator work stations, printers, Software etc for feeding 6.6 kV motors and distribution transformers. All feeders shall be protected through fast action numerical relays with Over-current, earth fault protection. Motor feeders shall be protected against overload, over-current, unbalance, locked rotor, under-voltage protection and higher number of starts (than



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allowed). Transformer feeders are provided with over-current, earth fault, transformer differential protection and Restricted earth fault protection.

b) Distribution transformers - 2.5 MVA, 6.6/0.415 kV ONAN with OCTC

c) PMCC (Power & Motor control centre) – 1 no. with 2 nos. Incomers, Bus-coupler with Auto / Manual changeover, Bus and Line PT, air circuit breaker, outgoing plant and motor feeders, numerical relays and Data concentrator with engineering and operator work stations, printers, Software etc for feeding MCCs, ASBs, LDBs, motor feeders (>= 75 kW) etc .

d) EPMCC (Emergency Power & Motor control centre)– 1 no. with 2 nos. Incomers, Bus-coupler with Auto / Manual changeover, Bus and Line PT, air circuit breaker, outgoing plant and motor feeders, numerical relays etc for feeding emergency loads.

e) MCCs (Motor control centre) – 3 nos. with 2 nos. Incomers, Bus-coupler with Manual Key interlock, motor feeders, SFU feeders for feeding motors (<=55 kW), MOVs.

f) ASB (Auxillary Switchboards) - 1 no. with 2 nos. Incomers, Bus-coupler with

Manual Key interlock for feeding auxiliary loads, welding receptacles, power panels etc.

g) LDB (Lighting Distribution boards) - 1 no. with 2 nos. Incomers fed through

lighting transformers, Bus-coupler with Manual Key interlock for feeding lighting loads.

7.2 EMERGENCY POWER

Emergency power shall be fed from one Diesel Generator (DG ) of required capacity placed near sub-station and hooked up with EPMCC. All the emergency loads including UPS, battery charger, vital loads such as drinking water, fire alarm, communication system etc. shall be fed from this DG.

7.3 220 V DC BATTERY SYSTEM

Critical loads such as Switchgear protection & control, Critical DC lighting shall be fed through DC battery Charger backed up with Ni-Cd battery set suitable for feeding the critical loads for a period of minimum 2 hours.



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7.4 UPS POWER

Un-interrupted power supply is required for feeding critical instrumentation loads, public address system. Required capacity UPS backed up with Ni-Cd battery set for a period of minimum 30 minutes shall be provided.

7.5 EARTHING & LIGHTNING PROTECTION SYSTEM

Earthing and lightning protection shall be provided for the entire facility including all the units , buildings, structures, Switchyard with GI earth strip, GI Earth electrodes and wire rope so as to maintain earth grid of overall resistance not more than 1 ohm.

7.6 REACTIVE ENERGY COMPENSATION

Capacitor banks shall be provided at 6.6 kV level for reactive power compensation up-to minimum power factor of 0.9.

7.7 LIGHTING

Lighting for the entire facility shall be provided including light fixtures, lighting /power panels, lighting transformers, switches, junction boxes etc., maintaining minimum illumination levels. 25 % lighting shall be fed from emergency supply for taking care of emergency conditions. Critical DC lighting shall be provided in units and important building to avoid total darkness and evacuation purpose.

7.8 CABLES AND CABLE LAYING

For 6.6 kV , XLPE insulated, armored PVC sheathed FRLS cables shall be provided. For 415 V, PVC insulated armored PVC sheathed FRLS cables shall be provided. Cables shall be laid in cable trenches, trays as applicable. Minimum distance of 300 mm shall be maintained between 6.6 kV and 415 V cables. Fire alarm and communication cables shall be laid in instrumentation duct wherever feasible, else same shall be laid in road berms.



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7.9 FIRE ALARM SYSTEM

Addressable fire alarm system complete with Data Gathering and fire alarm panel (DGFAP), Repeater panels including multi-criteria smoke detectors, heat detectors, manual call points, Isolators, Exit signs, hooters, etc. with VRLA battery shall be provided for detection of fire in all the units, buildings & offsites.

7.10 PLANT ADDRESS SYSTEM

Plant address system complete with Plant communication exchange, Master call station, field call station, operator call station , loud speaker, beacon shall be provided.

7.11 TELEPHONE SYSTEM

Telephone system complete with telephone exchange, weatherproof and flameproof telephones, safe area handsets, IP telephones as required shall be provided.



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8 CONSTRUCTION METHODOLOGY

8.1 GENERAL

This chapter deals with the construction aspects associated with a storage facility of this nature. It highlights the various activities related to excavation and rock works. An effort has also been made to highlight details which are critical for satisfactory completion of works. In works of such nature, the Contractor is required to submit procedures of how works are intended to be carried out along with working philosophy for addressing key issues. Considering the stringent requirements of underground oil storage facility, it is imperative that the underground contractor executing the project has adequate past experience in the construction of underground rock caverns of comparable dimensions and design where as the above ground contractor will have experience in building facilities involving storage and handling of hydrocarbons. Owing to the scale and magnitude of the underground excavation involving 2.5 MMT and four independent and mutually exclusive units of the underground storage facilities, the following construction philosophy has been conceived and the contractual division of the project is made. There will be two underground excavation item rate construction contracts namely Part A and B consisting of civil works for underground rock caverns including the underground mechanical works where as the above ground process facilities, including all shaft and cavern equipment and mechanical works will be designated under Part C Contract. The integration pipeline system including offshore oil terminal off Padur will be executed under a separate contract package designated as Part D contract.

In view of its inherent nature, the u/g contractors would also perform certain component of above ground works such as the following: • Haulage roads to rock dumping area • Operation of rock dump area • Monitoring wells • Portal area • Shaft top area • Compound wall and associated works



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With an objective to ensure schedule completion times, Part A and Part B contracts will have to be started before Part C with built in interface. While the Part A and Part B contracts will be executed in Item Rate Construction Contracts, the Part C & Part D contract will be executed in LSTK basis.

8.2 DESIGN

The basic engineering design (BED) for the underground works will be carried out by the PMC / Owner and will be included in the bid document. The detailed design of the underground facilities will be provided by design team of PMC / Owner. Design of critical items related to the storage principle such as concrete barriers and the water curtain system shall be provided by the PMC / Owner. The field design, site supervision and geological mapping of the excavation works will also be provided the Owner / PMC; whereas only construction activities will be performed by the Contractor. The design philosophy for underground works will follow an observational approach, i.e. the original design assumptions are to be updated by means of the results from monitoring during construction, to allow for an optimized design. Further, the interface between design and construction processes should be given special attention with the objective to achieve consensus between the two parties of the Contractor’s organization. An active input of constructability aspects into the design process is considered as a crucial factor for a speedy construction. This process shall be facilitated by engaging Design Interface Manager having relevant experience, reporting directly to the Project Manager of the Contractor. The above ground facilities for the storage and the associated integration pipeline are planned to be executed under two LSTK contract, therefore, based on the basic design package, the detail engineering will be performed by the contractor for procurement, construction, mechanical completion, pre-commissioning and commissioning.

8.3 CONSTRUCTION ASPECTS

8.3.1 Access Tunnels

For construction purposes, two independent access tunnels are planned from the surface with access portal to allow for use of heavy equipment for excavation of the rock caverns and execution of underground civil and installation works. The accesses have been designed with the objectives of time schedule as well as safety during the excavation phase. Two access tunnels along with portals



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are considered so that the underground works can be carried out by two independent and mutually exclusive contractors. The detail design will have an influence on the dimensioning of access tunnels. Determining factors in the dimensioning of the access tunnel are the ventilation requirements of the caverns as well as the chosen method and equipment for mucking. The access tunnel must allow space for the ventilation ducts and for free passage of the intense two-way heavy construction traffic. In order to facilitate the mucking operations, the invert of the access tunnels are planned to be paved and properly de-watered.

8.3.2 Caverns

The caverns are planned to be excavated in multi stages involving heading and two or three benches. This will be dependent on the type of drill jumbos to be deployed. The excavation of the heading and benches will be undertaken by either through full face excavation or in a combination of pilot and side slashing. Conventional Drill and Blast technique will be used with horizontal drilling of blast holes for ensuring smooth control blast, reduced blast induced damage to the cavern wall and safe working condition.

8.3.3 Water Curtain System

Determining factors in the dimensioning of the water curtain gallery are the equipment to be used for excavation and mucking as well as the choice of method and equipment for water curtain borehole drilling. Pre-probing and grouting may be required during excavation. However, grouting in water curtain tunnels will be minimised and only be employed when;

a) In-leaking water endangers work safety, slows excavation progress or creates unacceptable draw down of ground water table.

b) Excessively leaking boreholes indicate that the water consumption during operation of the water curtain system become unacceptable.

The water curtain tunnels will as far as possible be used for hydro geological mapping and testing to identify structures which could require to be treated by pre-grouting during excavation of the underlying cavern galleries. The water curtain boreholes shall be charged through temporary arrangements for pressurization of boreholes so as to ensure saturation of rock-mass ahead of the cavern construction. No cavern excavation shall be allowed without at least 50m of advance saturation of the rock mass. Upon completion of the cavern



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excavation, the temporary arrangements of pressurization shall be dismantled and the water curtain gallery will be filled in with water up-to a defined level.

8.3.4 Drill & Blast

The drill pattern is decided based on the requirements regarding smooth and control blasting, local geological features and optimization of the pull or advance of excavation. Drill patterns and charge concentrations must be continuously modified throughout the construction period, to suit the local geological conditions. Contour and helper holes must be lightly charged to avoid excessive damage outside the excavation line. Due to the fact that these holes are lightly charged the distance to the nearest free surface is relatively small. The quality of detonators is crucial and the cost and time implications of a misfire are serious. For this reason a detonator supplier would have to be able to ensure the consistency of his product to the satisfaction of the contractor.

8.3.5 Scaling & Mucking

No person should enter into any section of recently blasted rock excavation until it has been scaled. Experienced rock workers must carry out scaling. Decisions often need to be taken on the spot as to whether the rockmass needs to be taken down or whether it can be safely secured using rock bolts and shotcrete. Mucking equipment must be sized in accordance with the tunnels to be mucked as well as the time constraints. In the case of the oil storage caverns, the space available allows for the use of large wheel loaders or face shovels. The access tunnel on the other hand is more restricted. The loaders may use a side tipping action or may haul the muck to a loading niche, which is blasted specifically for loading. In longer tunnels turning bays may be required for the trucks. The haul roads in the project including those in the tunnels and caverns is planned to be paved and maintained to reduce wear and tear on the trucks. The surface of the spoil dumps should be leveled and compacted for the same reason. Safety and quick turn around must also be considered on spoil dumps. Adequate arrangements should be made to ensure that trucks are standing correctly when dumping and that they do not fall off the edge of the tip while reversing or dumping. The mucking operation could be critical for completion on time.



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8.3.6 Geological Mapping

Geological mapping shall be performed by the Owner / PMC representative prior to application of rock support which will include shotcrete and pattern rock bolts. The geological mapping shall be performed by adopting Q-system and the determined rock mass class shall be the basis for rock support. Depending on the specific site conditions involving combination of critical joint sets leading to a possible wedge failure, should there be additional requirements, the engineering geologists will decide to install additional rock supports, as the need be.

8.3.7 Rock Support

Rock support will be decided based on the geological mapping and monitoring. The PMC / OWNER’s representative will perform the excavation face mapping and accordingly, based on the directive the contractor will install the rock support. The design forms the basis for the decision making process. The behavior of the tunnel section is monitored at certain intervals and locations, and the design for different rock classes is modified and optimized as the excavation progresses. Thereby, through an On the go Design approach, the necessary design optimization will be attempted. A combination of fully cement grouted rock bolts and fibre reinforced shotcrete provide the permanent rock support. The roof of all caverns and tunnels and sides of shafts shall be shotcreted. Additional certain critical areas of the cavern wall shall also be shotcreted. The shotcrete provides protection against loose pieces of falling rock. It further acts in conjunction with the rock bolts and to provide structural stability. It is essential that trials are conducted in advance of production to determine, compressive strength, short term strength development, setting time and adhesion to the rock surface, etc. Shotcrete must achieve rapid setting so that it will remain on the rock surface and allow a suitable thickness to be sprayed in one sequence. The short-term strength gain is important, particularly in poorer rock conditions, to allow the excavation cycle to proceed.



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8.3.8 Grouting

Probe holes will be required in advance of blast drilling to detect weak zones / water bearing zones in the rock that would require grouting. Requirement for pre-grouting will be furnished during construction based on the geological mapping of the water curtain gallery, and the predictive geological model prepared from face mapping of underground excavation. Pre-grouting by cement based grout is the preferred method of achieving the required tightness of the cavern complex. The optimal length of drilling and the most suitable grout mix design will be decided on site through an iterative process. Quite often seepage is detected after a blast. In the event of excessive seepage exceeding the design critical value, post-grouting is planned to be performed.

8.3.9 Shaft Excavation

The pump shafts are planned to be excavated top down to save time and offer early possibilities to arrange extra ventilation and emergency exits from the caverns. Above the roof of the cavern a key is excavated in the shaft to anchor the concrete plug. The exact location of the key is determined during the construction phase taking local geological conditions into account. The product inlet shafts could be excavated top down or by raise boring method.

8.3.10 Concrete Works

The concrete works to be executed for the underground storage facilities will comprise of the following: • Concrete Plugs in the access tunnels and shafts • Concrete Separation walls in connection tunnels between caverns • Concrete Floor on the final cavern invert • Concrete Floor in the pump pit • Concrete Pad / Bases for equipment installations • Mass concrete filling in shafts • Embedment of hot oil pipe on cavern floor Detail design for concrete plugs, separation walls, cavern floor and pump-pit are planned to be provided by the PMC / Owner under the Design of Critical Items for the purpose of storage.



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Concrete Barriers that shall be required to withstand a pressure differential shall be keyed into the rock. Barriers in large diameter tunnels and shafts contain a substantial depth of concrete. Provision must be made in the construction process to avoid large temperature gradients caused by the hydration of the cement. After hydration of the concrete, the Concrete Barrier will be cooled (refrigerated) by cooling coils installed in the concrete to achieve thermal shrinkage of the structure. In this status the final contact grouting between rock and concrete will be executed. When casting concrete against the uneven rock surface, it is impossible to completely fill all voids, particularly in the roof of access tunnels. Provision is made in the barrier for grouting these voids after the concrete has set. Some of the concrete barriers in tunnels will be arranged with a temporary manhole to allow for access through the barriers during the construction period. The concrete barriers in shaft shall be cast in two sequences. The first casting sequence will have box-out pipes for all casings for crude oil pumps and instrumentations and shall carry the load from all such pipes, including weight of water for pressure tests of casings. The second casting sequence will embed all casings to ensure vapour tightness. For the purpose of installation of submersible pumps and associated instrumentation casings and pipes shall be installed in the shafts. The shafts shall be backfilled with mass concrete above the concrete barriers, where in the casing pumps will be embedded. A support framework shall be provided on top of pump pit and for the casings. The cavern invert is covered by concrete slab to facilitate flow towards the pump pit. Provision for drainage will be made along the cavern side walls to ensure that the floor is not up-lifted by the water pressure underneath.

8.3.11 Dewatering

The dewatering system from caverns and tunnels should be planned in advance and installed as soon as is practical after the advance of the excavation face. Back-up power should be available for dewatering in the event of power cuts. Water running on the ramp is detrimental to the road surface increasing wear and tear on haulage trucks and should be taken care of.



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8.3.12 Ventilation

Ventilation is required to remove fumes from diesel powered construction equipment, rock particles suspended in the air and gases resulting from the detonation of the explosives during construction in order to provide a safe working environment. This can be achieved solely by the continuous supply of fresh air to the working face.

8.3.13 Muck Disposal

A speedy and continuous mucking out operation will be critical. The contractor will be required to plan the logistics of the muck disposal and maintain the haulage road and disposal area in such a way that muck disposal can be performed at all times. The muck disposal shall be done with required safety precaution and maintaining suitable slopes for haulage. While the selected site offer muck disposal alternatives, re-working of the rock debris will be beneficial for the proposed excavation works. This will offer both space availability and revenue. For the present study re-working of muck @ disposal site has been considered. To this effect, an additional land should also need to be identified by the Owner for reworking purpose.

8.4 SAFETY

The normal safety precautions that apply during ordinary construction work are also applicable to underground work. However there are several areas which need particular emphasis:

• Working with explosives. • While working under loose rock or unstable ground, scaling is a vital

operation. Wherever there is uncertainty, strong measures must be used. Experience is absolutely critical for decision making in these circumstances.

• Working in close proximity to mechanical equipment in confined spaces is always fraught with danger. Proper guardrails, screens should be installed and caution signage prominently displayed.

• Air Quality – To ensure optimal functioning of men and machinery, the quality and quantity of fresh air needs to be monitored and maintained.

• Noise – High noise levels have an extremely detrimental effect on the working environment, particularly in confined spaces. Care should be taken to adopt adequate measures to minimize noise from drilling and where compressed air is used.



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• Fire and Smoke – All necessary steps should be taken to protect against fire hazards and smoke extraction. This should be taken care of during procurement of construction plant and material.

• Communication and Access control system at the tunnel portal and records of all personnel working underground at any given time.

• Electricity – Sizing of switchgear and cables should be based on actual and prospective loadings. All circuit breakers / fuses shall be rated for 110% of normal load. Cables shall be properly terminated.

• Emergency exit – should be provided, in the pump shafts, as early as possible.

8.5 TESTING & COMMISSIONING

Cavern tightness testing shall be undertaken by respective underground contractors. Whereas for the commissioning purpose the underground contractors will provide assistance to the above ground contractor.

8.6 MAJOR CONSTRUCTION EQUIPMENTS

The following major construction equipments are planned to be deployed for the intended project completion schedule.

Sl. No.

Equipment Description Capacity Minimum number

required to be deployed

1 Hydraulic Drilling Jumbos. 2 booms+ basket (minimum)

4+1#

2 Grouting Equipments with automatic data acquisition system

Pumps, High speed mixers, agitators 2

3 Dump Trucks. 25T (minimum) capacity 25 4 Shotcrete Robots. 20 m3 4+1

5 Loaders. 6.5 m3 Front end

or 5.5 m3 side loading

4+1

6 Water Curtain Hole Drilling Rigs. Vertical / Inclined

Capable of drilling 100m

2 destructive drilling rig +

1 core drilling rig 7 Mobile Hydraulic lift platforms Min. reach of 24m 2

Note : Deployment for each contractor and (#) additional for stand by requirements.



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9 PROJECT EXECUTION, PLANNING AND CONSTRUCTION SCHEDULE

9.1 GENERAL

In general excavation of an underground storage cavern is undertaken through an access tunnel (inclined drift). While various factors contribute in deciding the methodology, availability of land around cavern site and the depth of the cavern are two most important considerations. The access tunnel is designed to handle/ accommodate the following: a) access of men and material into the cavern during construction; b) entry of all equipment required for the underground works c) removal of muck, simultaneously with the movement of men and material Underground excavation is carried out by conventional drilling and blasting cycle, in stages with the top heading being taken up first followed by excavation of the benches. The top heading is excavated with horizontal drilling for smooth contour of the crown, followed by the benches, which are either excavated by horizontal drilling or vertical drilling depending on the construction methodology with respect to the progress of the execution. The stages of excavation broadly involve construction of entry portal for access; excavation of access tunnel and / or shaft; excavation of water curtain tunnels; excavation of the storage caverns in stages; providing rock support as the excavation progresses; followed by concrete plugs to seal the cavern. Concurrently, water curtain boreholes are drilled from the water curtain tunnel and filled with water after being sealed. The storage cavern will also involve in-cavern mechanical works such as hot oil circulation pipe and its associated anchor blocks. For the purpose of product filling and evacuation and for evacuation of seepage water from the cavern pump pit, submersible pumps are installed through pipe-casings lowered from the surface through the shafts. A typical cycle of excavation includes the stages such as surveying and setting out; drilling probe-holes; marking the excavation face; drilling of blast-holes; charging of blast-holes; blasting; defuming; scaling; demucking; geological mapping; estimation of rock support; installation of shotcrete and spotbolts; ventillation; excavation face.



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Per cycle excavation progress achieved depends on various factors viz. the design requirements, blasting patterns and the nature of rock mass with a typical pullout or progress of 3.5 to 4.0 m vis a vis a blast cycle of about 10 to 12 hrs. During the entire excavation process, particular attention is given to ensure that the rock mass remains saturated with water even while excavation works are in progress. In view of the cavern size and excavation sequence, muck removal from the cavern face forms an integral part of the construction planning. Therefore, while a suitable site of adequate holding capacity is selected for muck disposal; the lead distance between the construction site to the disposal site is also very important. On completion of the excavation, the caverns are isolated and sealed by installation of concrete plugs. While this ensures confinement of the stored product, the shafts provide the necessary inlet and outlet pumping facilities.

9.2 PROJECT EXECUTION SCHEDULE

The excavation of underground rock caverns will be taken up by engagement of two underground civil contractors, with mutually exclusive scope of work and division of responsibility. PMC / Owner will provide detailed design of underground works and the associated design of critical items involving containment of stored products such as water curtain system and concrete works. While the PMC / Owner team stationed at design center will perform design related activities; the site team will ensure implementation of design at site including supervision of all excavation activities, performance of geological mapping, and site related design adoptions etc. The contractors will only provide construction services. The above ground facilities for the storage facilities and the associated integration system involving offshore oil terminal and pipelines will be executed by two independent LSTK contractors. Execution of the project would involve the following stages of activities: • Undertake Supplementary Investigations.

• Perform basic engineering, preparation of bid document for underground

facilities and pre qualification of bidders.



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• Bid evaluation and award of underground item rate construction contract (two nos. for the site at Padur with storage capacity of 2.5 MMT).

• Mobilization of contractors having similar past project experiences for underground facilities.

• Performance of detailed design of underground works and critical items pertaining to hydro-geologic containment of the stored products by PMC / Owner to be provided to the contractors. The PMC / Owner will also perform field engineering including site supervision of all underground excavation activities and performance of geological mapping etc.

• Perform basic engineering, preparation of bid document for aboveground facilities including connectivity to the existing facilities & additional new pipelines and prequalification of bidders.

• Bid evaluation and award of aboveground LSTK contract

• Mobilization of contractors having similar past project experiences for aboveground facilities.

• Concurrent performance of basic engineering and preparation of bid document for integration pipeline for the storage facilities envisaged from Padur to the proposed new SPM located off Kaup and pre-qualification of bidders.

• Bid evaluation and award of pipeline contract for the purpose of integration to the storage facilities.

• Mobilization of contractors having similar past project experiences for pipelines.

• Mechanical completion of underground caverns, above ground facilities, integration pipelines and Commissioning of all the facilities.

The detailed project execution schedule for the underground rock cavern storage at Padur is presented at A197-000-27 44 – Z001.



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9.3 PLANNING AND SCHEDULE

The construction schedule is based on the assumption that the project approval is in place, funds are allocated and the PMC is appointed for execution of the project. A time duration of 15 months is required for pre project activities such as land acquisition, statutory clearances, pre award bid engineering activities, formation of a team with limited FBC support for detailed engineering to be taken up for underground activities both at HO and site etc. Subsequent to the engagement of PMC, the estimated time required to construct the envisaged project is 66 months. The standard working week has been assumed to consist of 2 x 10 hr shifts per day, 6 days per week, with 12 Public Holidays per year falling on workdays. The average distance from the tunnel portal to the dumping areas is assumed to be 2 km. It is assumed that all necessary land will have to be acquired by the date of award of the contract for underground excavation works.

9.3.1 Mobilisation

To optimize deployment of resources, the basic infrastructure for the project should be in place before commencement of the production activities. The following must be accomplished during the initial phase: • Purchasing and Importation of specialist construction equipment • Establish Communications • Set up Godown and office in nearest population centre • Establish contacts with the necessary authorities • Purchasing Indigenous Equipment and Materials • Recruitment of personnel • Establishing Administration Organisation • Establishing Stores and Logistics Organisation • Accommodation for labour and staff • Construction of Warehouse • Obtain Explosives Permits and Establish Magazines • Establishing Electricity Supply and Back up Electricity Supply



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• Establishing Water Supply • Construction and Outfitting of Workshop • Construction of Site Access and upgrading of roads

9.3.2 Portal and Access Tunnel

Excavation of the Portal, stabilization through rock support installations and further excavation of Access Tunnel is on the critical path. These surface works for the portal are planned to be executed preferably in non monsoon period, else there will be substantial delay in over all construction. Average Progress of the Access Tunnel to the Curtain Gallery Junction is estimated as 11-15m / week. The rockmass in the initial segment of portal and access tunnel close to the surface will be relatively more weathered thus limiting progress. Further, during this phase, trials of drill patterns and explosives as also shotcrete trials are carried out. If water bearing fissures are encountered in this stretch, grouting trials also may have to be carried out. Therefore the net excavation progress in this tunnel segment is generally slow.

9.3.3 Water Curtain Gallery

Excavation of the Curtain Gallery and drilling of the water curtain holes fall on the critical path. The average progress of 14 to 20m / week is planned for the water curtain tunnel, while through deployment of DTH drilling rig, a minimum of 50 drilling meter per rig per day is considered for the water curtain borehole drilling.

9.3.4 Shaft

While excavation of the Shafts are not on the critical path but this should also be taken up concurrently, so as to avail the benefit of ensuring better ventilation for the cavern excavation. The pilot shaft is assumed to be sunk from the surface up-to the cavern crown there after it can be excavated and mucking can be done through the caverns.

9.3.5 Cavern

In the top heading, progress is assumed as approximately 15m /week/face. One team is allocated to each cavern pair. A team comprises one drill-jumbo, two loaders and approximately 6 to 8 numbers of 30 ton capacity trucks depending



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on the distance to the dumping area, two man-lifts, one or two shotcrete robots depending on the rock condition, one multi-hole grout rig, one worm pump for bolting, trucks and light vehicles for general transport. Reserve machines are necessary. The size of the reserve is dependent on the source of the machines. Bench excavation is planned to be carried out through horizontal drilling. In this study horizontal benches have been chosen as the optimum method for excavation. Adequate ventilation must be provided to avoid delaying progress. Extra machines cannot be used underground unless there is sufficient air. Rock Support capacity, particularly shotcreting capacity is critical for the top heading. Two shotcrete robots would be a minimum for this project.

9.3.6 Installation in Shaft

Installation of casing pipes in the shaft shall commence as soon as the shaft is excavated and all mucking operations have finished. On completion of all civil works in the cavern area, close to the pump pit, installation of the instrumentation cabling, detectors shall commence.

9.3.7 Concrete Works

The critical concrete works are the pump pit, the cavern floor, the shaft plug, and the final concrete plug in the access tunnel. Adequate time must be considered for construction of the concrete plugs as shrinking of the concrete must be complete before under taking contact grouting for ensuring cavern tightness.

9.3.8 Above Ground Installations

The construction of above ground installations are not on the critical path for this project and has been timed in such a manner that the mechanical completion will match with the cavern completion.

9.3.9 Pipelines & SPM

The construction of integration pipelines and SPM is also not on the critical path for this project and has been timed in such a manner that the mechanical completion will match with the cavern completion.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66

A APPOINTMENT OF PMC

B SUPPLEMENTARY INVESTIGATIONS 8

C UNDERGROUND CIVIL WORKS

1 PREPARATION OF ITEM RATE BID PACKAGE 5

2 ISSUE OF BID PACKAGE

3 BID SUBMISSION, EVALUATION AND AWARD 5

4 EXECUTION

4.1 DETAILED ENGINEERING AT H.O. & SITE / DESIGN OF CRITICAL ITEMS (BY OWNER / PMC) 42

4.2 CONSTRUCTION

i ACCESS TUNNEL 18

ii SHAFT WORKS (INCL. VERTICAL PIPING) 42

iii WATER CURTAIN TUNNEL & BORE HOLES 24

iv CAVERNS EXCAVATION AND OTHER WORKS 30

v UG MECHANICAL WORKS 10

vi CONCRETE WORKS 12

viI CHARGING OF WATER CURTAIN SYSTEM 3

D ABOVEGROUND FACILITY WORKS

SL NOMONTHDURATIO

N(MONTHS)

ACTIVITY DESCRIPTION

T

1 PREPARATION OF LSTK BID PACKAGE 8

2 BID SUBMISSION, EVALUATION AND AWARD 6

3 EXECUTION

3.1 DETAILED ENGINEERING 27

3.2 PROCUREMENT 30

3.3 CONSTRUCTION 34

E OFFSHORE / ONSHORE PIPELINE WORKS AND SPM INSTALLATION

1 BASIC ENGG. AND ONSHORE/ OFFSHORE SURVEY 9

2 PREPARATION OF BID DOCUMENT 6

3 TENDERING AND AWARD 6

4 EXECUTION

4.1 DETAILED ENGINEERING 12

4.2 PROCUREMENT (SPM & LINEPIPE) 12

4.3 CONSTRUCTION 9

4.4 COMMISSIONING 6

F COMMISSIONING OF CAVERNS 3

LEGEND ISSUE TENDER DOCUMENT AWARD CONTRACT ISSUE OF BID PACKAGE FREE ON BOARD DELIVERY

A197

MOP & NGA197-000-2744-Z001-0

DOCUMENT NO

Tusharkanti Nanda Dr. Atual NandaJageshwar Singh

PREPARED

PROJECT :

PREPARATION OF DFR FOR PHASE II OF STRATEGIC STORAGE OF CRUDE OIL FOR GOVT. OF INDIA

PROJECT EXECUTION SCHEDULE FOR STORAGE OF CRUDE OIL IN

UG ROCK CAVERNS AT PADUR (2.5 MMT)JOB NO. : 0 15-Mar-13

CHECKED/ APPROVED

ISSUED WITH DFR

CLIENT REV DATE PURPOSE

T FOB

T

T

MOP & NG BYC C /

REVIEWED BYO

BYCLIENT : NO. DATE PURPOSE



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10 OPERATION AND MAINTENANCE

10.1 GENERAL

The storage facilities proposed to be built under the Phase II storage program, are likely to be executed under PPP mode. Unlike the operational philosophy of Phase I storage facilities, the Phase II storage facilities are likely to have a different operation philosophy which will be governed by several factors such as frequency of filling and evacuation and intermittent supplies to the refineries. Accordingly, a broad operation and maintenance philosophy has been presented. The nature of the oil storage facilities demands that the plant operates at peak operational levels at all times. In order to ensure that, the owner must depute competent personnel to operate and maintain the plant. It is suggested that the designated operation team join the project during the final stages of construction, so that a seamless handover can be effected. The proposed plant Operation and Maintenance staff structure would preferably be as under:

Terminal Manager

Administration & Safety Officer

Account Manager

Superintendent Mechanical

Superintendent Electrical & Maintenance

Accountant

Plant operations

E&I Foreman

Technicians

Superintendent Civil

Civil Foreman

Mechanical Foreman

Technicians



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The total staff strength considered for operation of the storage facilities will be as under: • Executive 13 Nos. • Non Executive 18 Nos.

10.2 OPERATION AND MAINTENANCE PHILOSOPHY

The basic operation philosophy for the plant has already been described in the preceding chapters. An operations manual is planned to be prepared on completion of the detailed engineering and on completion of commissioning the manual will be updated. Inputs would be taken from the operation philosophy and control logic of the refinery and the port authorities. The key issues that need to be considered are: • Prior to taking over the plant, proper and exhaustive training is imparted to

the operations staff, on and off site.

• Inventory of spares, as recommended by the manufacturers is maintained at all times.

• Local availability of critical equipment and spares is explored.

• Manpower training on a regular and continuous basis is done.

• Equipment maintenance schedules are drawn up and strictly adhered to.

• All major and minor piece of equipment are tagged and logged.

• Checklists are drawn for all maintenance routines.

• Interlocks are NEVER bypassed.

• Control and emergency equipment are tested at regular intervals.

• Fire drills are carried out periodically.

• Critical safety related issues like earthling, flaring, over/under pressure, over temperature, etc are never neglected.



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• Any permanent changes carried out in the plant be immediately reflected in the drawings, stores order info log, control software, etc.

• Access to plant and control rooms is strictly restricted.

• No major changes are made in the plant control and protection schemes, without concurrence of the State Electricity Board.

• Visual checks for corrosion, water logging, sparking / charring etc in above ground process installations, are made at regular intervals and remedial action taken immediately.

• Cables / terminations are checked for integrity at regular intervals.

• All faults / alarms are investigated and reported.

10.3 UTILITIES AND OPERATIONAL DATA

The requirement of consumables for one year has been estimated considering the one cycle of cavern being filled and evacuated.

Utility Quantity Unit / year Electrical Energy 18,000 MWh Industrial Water 12000 m3 Potable Water 220 m3 Diesel 150 m3

10.4 HEATING OF CRUDE OIL

For the heating of the crude oil approximately 75% is generated by the boiler and 25% is generated by pumping. 2/3 of the heat losses are towards the seepage water and 1/3 is due to heat losses through the rock, considering stable conditions (750 kW).

10.5 INDUSTRIAL WATER

The water consumption is based on a continuous water supply of 120 m3/h to the water curtain.

10.6 POTABLE WATER

The requirement of potable water is considered as 600 litres / day per operational staff of 31 persons.



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11 STATUTARY APPROVALS, CODES AND STANDARDS

11.1 GENERAL

The concept of underground oil storage is well established internationally. However, as this is still new in the Indian context, approval from the various governmental agencies will be required, and it is recommended that the following procedures be adopted: Approval of the design of the facility, based on the Swedish Regulations for assessment of underground rock cavern storages. For specific installations, existing Indian Regulations may be considered, wherever applicable. Approval from the Chief Controller of Explosives in India, for the principle of storage of crude oil in caverns The layout of the plant should comply with all the relevant directives of the Ministry of Environment and Forests, in particular to the requirement pertaining to Compensatory Afforestation, effluent disposal and pollution control. A 50 m wide green belt all around the plant, shall be maintained. The plant shall be laid out as per the requirements of API and relevant Indian standards, regarding Classified Area installations. The fire protection system for the facility should be in accordance with the Indian codes of practice and NFPA. The code of practice followed elsewhere in the world, for similar facilities shall form the basis for establishing the methods and principals for obtaining necessary approvals for the strategic storage programme in India. Risk Analysis and Environmental Impact Assessment for the facility shall be conducted and approved as per Indian Regulations. All mechanical, electrical and instrumentation designs shall comply with the relevant Indian and/or equivalent international standards. In this context, the international experience acquired over the past four decades has clearly substantiated the inherent safety of the underground rock cavern storage facilities, as compared to above ground steel storage.



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11.2 CODES OF PRACTICE

The underground storage cavern facility will be designed as per the following codes of practice: • Layout

As per OISD 130, Oil Industry Safety Directorate Standard for layout for oil and gas installations

• Protection

As per OISD 116, Oil Industry Safety Directorate Standard for fire protection facilities for petroleum refineries and oil gas installations

• Guidelines for Storage of Petroleum

As per Petroleum Rules - Chief Controller of Explosive Act

• Civil Works

Indian Standards • Process

- Safety and Security

Chief Controller of Explosive Act.

- Pressure piping

Applicable parts of API / ANSI B. 3 1, Code for Pressure Piping. - Process Valves

API Standard (American Petroleum Institute).

Steel pipe flanges and flanged fittings: ANSI B 16.5. - Submersible product pumps

European Standard or ANSI-standard.



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- Oil separator

API Publication 42 1. - Fire protection equipment

Applicable parts of NFPA (National Fire Protection Association). - Electrical installation and equipment

Applicable IS and IEC standards.

- Instrumentation

Applicable IS and IEC publications. - Quality Systems

ISO 9001

ISO 14001



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12 SCHEME FOR EIA AND RRA

12.1 GENERAL

Everything we do in our daily life affects our surroundings, or the environment we live in. This could be by our presence, the direct actions we do, or more indirect by the decisions we take. In many cases the decisions we take affect our environment with a grade several magnitudes greater than what our direct actions do. In order to be certain that we do take the correct decisions we have to assess the possible impacts prior to our decisions. We look upon working environment, safety and environmental issues with the same philosophy and within the same system. These questions are so intertwined in practical life it is impossible to separate them, therefore we choose to integrate them from start. An event (i) that occurs due to our activities, actions or decisions might result in a positive or negative impact on the environment. This is then defined as a environmental consequence (ci). If we are certain that the consequence will occur as a result of an event we know will happen, it has a probability of one (pi=1). If it might occur, maybe as a function of a abnormal situation, in other words, the probability is between zero (pi =0) and one (pi =1), it poses a risk (ri). In this study the following definition is used;

Risk is a function of probability and consequence: ( )iii cpfr ,= Depending on the stage of our project, our decisions will have different degrees of consequences. Generally, impact will decrease as a project develops. If we divide the life of an underground oil storage facility into three main phases, the impact of our decisions will be as follows: The operational phase will be the one where actions, or lack of actions, might have the most severe impact, but the design phase is without doubt the one where we decide what possible consequences that might become the effect of our activities. Our decisions and actions might also affect the possibility of something to occur, hence affect risk. This section will specify control philosophy and contains a conceptual impact and risk assessment and a general site sensitivity description. Finally, suggestions for environmental management system that should be adopted during the construction phase have been made.



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The rapid Environmental Impact Assessment (EIA) study will include the

following :

• Assessment of prevailing baseline environmental quality within the impact

zone based on the duration and season of field studies.

• Identification, qualification, prediction and evaluation of significant impacts

due to construction and operation of proposed project on different

environmental components.

• Evaluation of pollution control measures and delineation of Environment

Management Plan(EMP) outlining additional control measures to be adopted

for mitigation of possible adverse impacts.

12.2 BASELINE ENVIRONMENTAL STATUS AND IMPACTS.

Keeping in view the nature of activities related to the proposed underground rock

cavern project as well as the guidelines of Ministry of Environment & Forest

(MoEF), the following environmental components are to be covered under

baseline study:

• Air Environment

• Noise Environment

• Water Environment

i. Surface water characteristics

ii. Ground water characteristics

iii. Biological characteristics

• Land Environment

• Biological Environment

• Socio-economic Environment

Based on the above baseline data, prediction of impact must be done. While the

identified factors may not have any adverse impact, under Socio-economic

environment, both positive and negative impacts should be highlighted.



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12.3 ENVIRONMENTAL IMPACT STATEMENT

The proposed storage in underground rock caverns is intrinsically safe compared to above ground storage of similar quantity at one location w.r.t floods, cyclone, earthquake, sabotage / war threats etc. Thus, as part of the study, Environmental Impact statement is required to be prepared, concerning the following: • Air Environment

• Noise Environment

• Water Environment

• Land Environment

• Biological Environment

• Socio-economic Environment

12.4 ENVIRONMENTAL MANAGEMENT PLAN

The results of baseline status, prediction of impacts and the resultant environmental impact statement must have been duly considered for delineation of pragmatic environment management plan during construction and operation phases. The major issues to be considered are listed below: Construction Phase

• Preparation of site for proposed surface facilities will involve the excavation

and movement of substantial quantities of soil, rock and unstable material.

During dry weather conditions it is necessary to control the dust by suitable

dust suppression methods.

• When explosives are detonated in hard rock, the CO and nitrous fumes are

expected to be generated. Proper ventilation is to be provided and

maintained in the caverns and tunnels as per prescribed DGMS standards.

• The excavated rock is required to be transported to the identified dumping /

storage sites. For this purpose the approach road would necessitate

strengthening / widening / coal tar (Bitumen) lining to facilitate heavy

vehicular traffic



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• Proper safety measures are to be provided for the construction workforce to

avoid accidents during underground construction activities

• The onsite workers are to be motivated to utilize personal safety devices

related to noise and vibrations like earmuffs, ear plugs, safety shoes

/gumboots, hand gloves etc.

• Proper trained/skilled workforce only to be employed with necessary

emergency protective facilities for underground construction and also under

the supervision of qualified/experienced personnel

Operation Phase

• The stacks corresponding to Boiler, DG set, and flare shall be planned with

appropriate heights at the identified location for surface facilities to achieve

proper dispersion of air pollutants, specially keeping in view the surrounding

terrain.

• The proposed Fuel oil/Furnace oil for boiler shall be substituted with low

sulphur fuel.

• Suitable HCs/VOCs monitors shall be installed at critical locations

(Pumps,Valves, flanges, joints, bends in pipeline etc.) with compatible online

data recording and alarm system at the control room

• Monitoring of corrosion and fatigues of pipelines, valves, heat exchangers,

cables etc. shall be carried out at scheduled intervals

• The possibility of hydrocarbon vapour recovery and re-injection back into the

cavern system during crude oil filling, discharge and excess pressure/safety

vent operation periods shall be explored and implemented.

• Stacks connected to Bolier and DG set shall be provided with online monitors

forSO2, NOx and CO emissions.

• Ambient air quality w.r.t. S02, NOx, HCs, CO and secondary air

pollutants(aldehydes, oxidants) should be regularly monitored as per

norms at and around the proposed project site.



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• The fugitive emissions of HCs from storage facilities shall be prevented

through adopting the suitable measures

• Acoustic/noise control enclosures for the major surface equipment

• Acoustic insulation on piping, wherever necessary

• Acoustic insulation for pumps, compressors etc.

• Noise level monitoring at the project site on regular basis

• The ETP for seepage water treatment should be constructed

• A treated effluent pond (open) with minimum five days retention capacity

shall be constructed for conducting bio assay test prior to reuse of treated

effluent.

• In view of limited work force envisaged at project site during normal

operation, the sanitary waste at project site shall be managed through

properly designed septic tank system.

• A record of seepage water generation shall be maintained along with other

sources of wastewater generation at project site.

• The critical parameters such as pH, oil & grease, hydrocarbons, sulphide,

DO,BOD, COD etc. should be monitored on regular basis prior to reuse of

treated effluent.

• The ground water quality monitoring with special reference to oil & grease as

well as hydrocarbons to be done at different locations around the project site.

• Variations in ground water table shall be monitored from the beginning of

construction phase at regular intervals periodically in the vicinity of project

site.

• Implementation of appropriate rain water / surface drainage system with an

objective of rainwater harvesting at project site.

• Maintain the data record corresponding to quantity and characteristics of oily

sludge generation at project site

• Implementation of Corporate Social Responsibilities (CSR) Initiatives for the

nearby villages and environmental conservations for the surroundings.



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12.5 RAPID RISK ASSESSMENT STUDIES

The Rapid Risk Assessment studies need to include design, construction and operation of the facilities. The following significant issues are to be considered for risk assessment studies :

• Review of standards, practices and methods for safe environmental friendly

design; construction and operations of the underground cavern storage

facilities.

• Compliance to all regulations, legislations, norms for the facilities.

• Monitoring of safety aspects during construction and operation of the

facilities.

• Accidental release of crude oil during transportation, filling & evacuation and

handling of storage operation

• Risk communication with local residents, government, regulatory agencies as

well as Disaster Management / Emergency Preparedness Plan.

The objective of RRA study to encompass the following

• To assess safety of the proposed storage caverns both design and

construction aspects.

• Delineation of vulnerable surface facilities on the basis of hazard

identification

• Simulation of credible accidental scenarios, computation of damage

distances for significant scenarios based on consequence analysis.

• Assessment of risks under worst possible natural calamities including

Earthquake, Flood, Tsunami etc.

• Delineation of over all risk mitigation measures and approach for Disaster

Management Plan

12.6 RISK ASSESSMENT

The overall risk assessment could broadly be categorized to two components viz. underground rock cavern storage and the associated above ground facilities with an interface at the shaft level



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Underground rock caverns With the baseline parameters derived based on interpretation and inferences and adopted for the project should be studied along with the design assumptions of the facilities. Thereafter, the probabilistic assessment of geo-technical hazards should be carried out, followed by possible consequence scenarios. This will follow, the exposure Assessment Matrix Table, as per the guideline of Directorate General of Mines Safety (DGMS) so as to attribute exposure ratings to various conceived hazards, and its likelihood of presence either for project facilities or general public within the sphere of influence of the hazard. Above ground facilities Based on the principle of Maximum Credible Accident (MCA) Analysis, the risks associated with above ground facilities are to be studied, which would include Fire Explosion Index of each units. The FEI tool would help in quantitative hazard identification and further evaluation of loss potential of all the units in the process area. The units which comes under server and heavy categories of hazards are to be studied with the help of consequence analysis.

12.7 RISK REDUCTION MEASURES & DISASTER MANAGEMENT PLAN

Based on the RRA studies, specific recommendations are to be provided for possible risk reduction measures, which should also include adequate training to the personnel working in the installation, so as to have preparedness to handle exigencies. The surrounding populace covering all strata of society should be made aware of the safety precautions to be taken in the unlikely event of any mishap within the installation.

12.8 APPROACH TO DISASTER MANAGEMENT PLAN

The objectives of Disaster Management Plan are given below: • Obtain early warning of emergency conditions so as to prevent impact on

personnel, assets and environment;

• Immediate response to emergency scene with effective communication network and organized procedures



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• Ensure safety of people, protect the environment and safeguard commercial considerations.

• Minimize the impact of the event on the facilities and the environment, by minimizing the hazards as far as possible and the potential for escalation.

Following are the key elements of Disaster Management Plan:

• Basis of the plan

• Accident/emergency response planning procedures

• Onsite Disaster Management Plan

• Offsite Disaster Management Plan

Disaster Management Plan: On-site Fire is a major possible hazard. The scenario of fire according to Maximum Credible Accident analysis MCA are the accidental release of crude oil from pipeline and associated facilities leading to jet fire and pool fire. The establishment of an 'EMERGENCY CONTROL CENTRE' to co-ordinate emergency response activities within a relevant area is essential. Emergency control center should be equipped with the following:

• An adequate number of telephones • Wireless communication system with adequate number of portable handsets • A list of external agencies likes Fire Brigade, Police, Hospitals, Port, and

neighboring Industries, Telephone co. etc. • Drawing of Pipeline network for the Mangalore site • Source of safety and fire protection equipment

Disaster Management Plan: Offsite Identifying the disaster potential scenario and advance planning to combat and minimize the damage to nearby life, property & environment

• To protect the inhabitation around the pipeline against the exposure to fire and to provide alternate safe shelters

• Rescue, relief, assistance to the people in the work/community effectively and efficiently based on actual needs



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• Collecting information locally in advance and taking further steps to mitigate it • Identifying persons affected and extending assistance to the causalities • Efforts to make the situation normal at the earliest after the disaster • To take adequate measure for rehabilitation



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13 COST ESTIMATE

13.1 GENERAL

The underground rock cavern crude oil storage of 2.5 MMT capacity is proposed to be set-up at Padur, Karnataka. The strategic storage facilities comprise of underground rock cavern storage, above ground filling and evacuation facilities, a new captive SPM located off the coast of Kaup, 48" diameter submarine pipeline, approximately 18 km upto inline booster pumps near LFP and a 5 Km long and 42” pipeline from booster station at LFP to storage cavern. The cost estimate for the underground storage facilities excluding the financing charges works out to Rs. 2226.36 Crores including foreign exchange component of Rs. 128.31 crores as presented herewith. The capital cost estimate excludes working capital margin and crude inventory cost. The associated proposed new SPM & offshore pipeline integration cost works out to Rs. 895.55 Crores including foreign exchange component of Rs. 281.51 Crores. The cost estimate is as of March 2013. The total cost includes all taxes, duties, land cost, Owner's cost, PMC/ Back Up Consultancy cost and contingency. This also includes cost towards construction site facilities, start up and commissioning of facilities. A cost provision has also been kept for Corporate Social Responsibility (CSR) and Infrastructural works say rerouting of road, power transmission lines etc. In view of the envisaged requirement of re-working of muck, additional land will also be identified and a cost component towards lease of such land has also been kept. The accuracy of cost estimate for the underground storage facilities may be considered as + 10%. The accuracy of cost estimate for the SPM & pipeline integration facilities may be considered as + 30%. The planned mode of execution of the project is as under:



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a) Two Item Rate Construction Contract for Underground civil works and

associated in ground mechanical works

b) LSTK contract for above ground filling and evacuation facilities

c) LSTK contract for new SPM & offshore integration pipelines. The detailed engineering of the underground excavation works including site supervision and geological mapping of the excavation activities will be performed by a team from Owner / PMC. In addition, the design of critical items will also be performed by the PMC with limited support of FBC.

13.2 FACILITIES AT CRUDE OIL STORAGE TERMINAL

The main elements of the underground crude oil storage facility are: • Four U shaped cavern units • Water Curtain for maintaining ground water levels • Two vertical shafts per cavern units from the surface to the cavern for all

piping and instrumentation of the cavern as well as pump maintenance • Temporary Access Tunnel to Caverns and Water Curtain Galleries. • Seventeen submersible crude oil pumps for evacuation of the oil from the

caverns and circulation each of 1600m3/hr. • Nine submersible seepage water pumps each of 50m3/hr. • Boiler and Heat Exchange system for heating the product. • Vapour Control System and Flare Stack. • Water Treatment Plant for seepage water from the caverns. • Fire Protection System. • Power Distribution and Cabling • Back-up Power Supply. • Nitrogen Inertisation of the cavern during filling and evacuation • Instrumentation and Control • All Piping and Valves within the facility. • Above ground facilities civil works including control rooms, equipment

foundations, piping and cabling trenches and provision for sanitation. • Main line pumps (3+1) each of capacity 3300 m3/hr;



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• Bulk materials like piping, electrical and instrumentation, civil works and Buildings.

• All other facilities like Raw / Drinking water system, Fire Protection system, WWTP and Insulation and Painting

• New captive SPM & 48”OD & 18Km offshore pipeline and 42”OD & 5 Km onshore pipeline and four (3 W+ 1 S) inline Booster Pump of 3300 m3/hr.

• Temporary Facilities necessary for construction process such as 100% back up power supply, fully equipped workshop, sedimentation and water treatment facilities, access roads etc.

13.3 BASIS OF CAPITAL COST ESTIMATES

13.3.1 Reference Document

The cost estimate has been prepared based on the following:

• Equipment List & MTO for Bulk material i.e. Electrical, Instrumentation and Civil works for above ground works.

• M.T.O for Under Ground Works. • SPM & associated Pipeline works

13.3.2 Exclusions

Cost component towards the following aspects have been excluded from the Project cost estimate:

• Exchange rate variation • Margin Money • Owner Financing Charges • Township & Infrastructure Facilities • 2 Years Operation & Maintenance Spares • Crude Oil Cost

13.4 ESTIMATION METHODLOGY

Cost estimate is based on cost information available from in-house cost data, Budgetary Quotation and Basic Engineering inputs. Estimate accuracy is targeted at ±10% for underground facilities & ± 30% for SPM & Linepipe



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13.4.1 Under Ground Works

Estimate for underground works at Padur has been prepared using MTO’s and In-house cost data.

13.4.2 Above Ground Works

Estimate for above ground works at Padur has been prepared using equipment list / MTO and using in-house cost data. a. Piping / Electrical / Instrumentation

The cost of piping items like pipes, valves, flanges & fittings has been estimated using indicative MTO’s provided.

b. Electrical The cost of electrical items has been estimated using indicative MTO’s provided. c. Instruments The cost of instruments has been estimated using indicative MTO’s provided. d. Spares The cost provision for mandatory spares at each of these stations is taken on factor basis. 2 Years Operation & Maintenance spares have been excluded from cost estimate. e. Erection works The cost of erection works for Mechanical Equipment and bulk materials such as Piping, Electrical and Instrumentation Equipment estimated on factor basis. f. Civil works Cost provision for civil works has been provided on MTO basis.

13.4.3 Integration Pipeline System

Cost estimation for the integration pipeline system has been worked out for 48" diameter pipeline, approx.18 km upto inline booster pumps near LFP and a 5 Km long and 42” pipeline from booster station at LFP to storage cavern



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Cost estimate is prepared for all other equipment, including route survey, ROU, SCADA, Telecom etc. as per equipment list / M.T.O referring in house cost data. a. Piping / Electrical / Instrumentation The cost of piping items like pipes, valves, flanges & fittings for stations has been estimated on factor basis. b. Electrical The cost of electrical items is based on factor basis and in house cost data. c. Instruments The cost of instruments is based on factor basis and in house cost data. d. Spares The cost provision for mandatory spares at each of these stations is taken on factor basis. 2 Years Operation & Maintenance spares have been excluded from cost estimate. e. Erection works The cost of erection works for Mechanical Equipment and bulk materials such as Piping, Electrical and Instrumentation Equipment estimated on factor basis. f. Civil works Cost provision for civil works has been provided on factor basis.

13.4.4 Indirect Costs, Exchange Rates and Statutory taxes/duties

a. Indirect Costs, Exchange Rates 1 US $ = Rs. 54.75 1 Euro = Rs. 71.28 1 NOK = Rs. 9.55 Ocean Freight 5.0% of FOB cost of imported equipment Port Handling 2.0% of FOB cost of imported equipment Inland freight 5% of FOB cost of imported equipment and ex-works cost of

indigenously sourced equipment. Insurance 1% of total cost



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b. Statutory Taxes and Duties

Custom Duty (Project Rate) 25.85% of CIF cost of imported equipment Excise Duty 12.36 % of ex-works cost of indigenously sourced

equipment. Sales Tax 4% (without Form-C) of ex-works cost of

indigenously sourced equipment including excise duty.

Works Contract Tax + Service Tax 4% Works Contract tax + 4.94 % of Service tax Entry Tax 2% of (Supplies + In directs) Service Tax on Engineering 12.36% (12% Service Tax + 3% Education Cess)

c. Escalation during execution Provision has been made for escalation during project execution for procurement.

13.4.5 Project Management, Detailed Engineering, Procurement Services & Construction Supervision

Cost provision for the services of project management, detailed engineering, procurement services & construction supervision assistance is provided on factor basis. For the underground unlined rock caverns storage alternative while no back up consultancy services are considered. For the purpose of review of the critical item design such as water curtain system for containment and concrete plugs for sealing of caverns, provision of limited efforts from Back up consultant has been included. The detailed engineering of the underground excavation works including site supervision and geological mapping of the excavation activities will be performed by a team from Owner / PMC, which would also include engagement and support of FBC. Service tax @ 12.36% is also been considered.

13.4.6 Land cost, Land Development Cost & Rehabilitation

A cost component of Rs 100 Crores has been considered for land cost & associated rehabilitation activities. An additional Rs. 20 Crores has been provisioned for taking additional land in lease so as to ensure re-handling of muck.



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13.4.7 Township & Infrastructure Facilities

No such provision has been kept for Township & infrastructure development

13.4.8 Owners Construction Period Expenses

The cost provision for owner’s construction period expenses has been made on factor basis.

13.4.9 Corporate Social Responsibility

A cost provision of Rs. 5 Crores has been kept under corporate social responsibility head.

13.4.10Start-up & Commissioning

The cost provision has been made on factor basis.

13.4.11 Owner’s Contingency

Provision for contingency has been made @ 5% of capital cost. This provision has been kept to take care of inadequacies in estimate basis definitions (including design and execution) and inadequacies in estimating methods and data elements.

13.4.12Working Capital Margin

The working capital margin has been excluded from the capital cost estimate. 13.4.13Owner’s Financing Charges This is excluded from the capital cost estimate.

13.5 ANNUAL OPERATING COST ESTIMATES

The storage facilities proposed to be built under the Phase II storage program, are likely to be executed under PPP mode. Unlike the operational philosophy of Phase I storage facilities, the Phase II storage facilities are likely to have a different operation philosophy which will be governed by several factors such as frequency of filling and evacuation and intermittent supplies to the refineries. Accordingly, a broad operation and maintenance philosophy has been presented.



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Further, the operating cost estimate has been attempted considering fixed costs and variable costs corresponding to one single filling and evacuation operation. The annual operating cost for the proposed storage facility has been worked out and is presented as an enclosure herewith.

PROJECT:

COST ENGINEERING DEPARTMENT

SL. D E S C R I P T I O N ALL COST IN RS. LAKHS JOB NO. A197

NO. CLIENT ISPRL

Fc Ic TOTAL LOCATION Padur

CAPACITY 2.5 MMT

PRODUCT Crude Oil

A ABOVE GROUND FACILITIES 77 01 424 74 501 74

B UNDER GROUND FACILITIES 1201 33 1201 33

Detailed Project Cost

SUB-TOTAL (1)... 77 01 1626 07 1703 07

2 ENGINEERING COSTS ESTIMATE VALIDITY

2.1 FOREIGN BACKUP CONSULTANT 40 00 40 00

2.2 WITHHOLDING TAX @ 10% 4 00 4 00 Mar-13

2.3 R & D CESS 2 00 2 00

2.4 P.M.C CHARGES + DETAILED ENGG. 177 73 177 73

2.5 SERVICE TAX @ 12.36 % 21 97 21 97 EXCHANGE RATES

1USD = Rs 54.75

1EUR = Rs 71.28

SUB-TOTAL (2)... 40 00 205 70 245 70 1NOK = Rs 9.55

3 SITE RELATED COSTS

3.1 LAND FOR TERMINALS/STATIONS 100 00 100 00

3.2 TOWNSHIP EXCLUDED Custom Duty = 25.85%

3.3 INFRASTRUCTURE FACILITIES 5 00 5 00 Excise Duty = 12.36%

3.4 CORPORATE SOCIAL RESPONSIBILITY 5 00 5 00 CST w/o C Form= 4.00%

3.5 LAND FOR MUCK DISPOSAL 20 00 20 00 WCT= 4.00%

Service tax= 4.94%

SUB-TOTAL (3)... 130 00 130 004 OTHERS

4.1 OWNER'S CONST. PERIOD EXPENSES 5 20 15 59 20 79

4.2 START UP & COMMISSIONING EXPENSES 20 79 20 79

SUB-TOTAL (4)... 5 20 36 38 41 58Satish

Kumar/S.K.Kohli

SUB-TOTAL (1+2+3+4)... 122 20 1998 14 2120 35

Ramesh Kumar

5 CONTINGENCY 6 11 99 91 106 02

K.K.Chopra

SUB-TOTAL (1 TO 5)... 128 31 2098 05 2226 36 S U M M A R Y

6 WORKING CAPITAL MARGIN MONEY

SUB-TOTAL (1 TO 6)... 128 31 2098 05 2226 36 DOCUMENT NO. A197-DR-6842-0002

REVISION NO. 0

7 FINANCING CHARGES DATE : 25-Mar-13

PAGE :

T O T A L C O S T ... 128 31 2098 05 2226 36 FILE NAME

Format no. 5-6842-1150-F1 Rev.1

Strategic Storage of Crude Oil Project at Padur

(Phase-II)

PROJECT MANAGER

PROJECT COST SUMMARY

TYPE OF ESTIMATE

EXECUTION METHODOLOGY

APPROVED BY

A/G ---> L.S.T.K

OVERALL PROJECT COST

U/G --> Conventional

PREPARED BY

REVIEWED BY

TAXES / DUTIES

Dr. A. Nanda

EXCL

EXCL

mailto:+@SUM(D29:D34)


Reverse Tendering

COST SUMMARY

JOB NO. A197

SL. D E S C R I P T I O N CLIENT ISPRL

NO. LOCATION Padur

Fc Ic Sc TOTAL CAPACITY 2.5 MMT

LICENSOR

1 MAJOR ITEMS

1.1 UNDERGROUND STORAGE CAVERNS 233 38 896 66 1130 04


ESTIMATE VALIDITY

CUSTOMS DUTY = 25.85%

EXCISE DUTY = 12.36%

C.S.T w/o C form = 4.00%

W.C.TAX 4.00%

SUB-TOTAL (1.1 TO 1.10)... 233 38 896 66 1130 04 Service tax = 4.94%

2 INDIRECT COSTS

2.1 OCEAN FREIGHT

2.2 CUSTOMS DUTY

2.3 PORT HANDLING

2.4 INLAND TRANSPORTATION

2.5 EXCISE DUTY PREPARED

2.6 CST without C form Satish Kumar/S.K.Kohli

2.7 SERVICE TAX 59 39 59 39 REVIEWED

2.8 WORKS CONTRACT TAX Ramesh Kumar

2.9 INSURANCE 11 89 11 89 APPROVED

SUB-TOTAL (2)... 11 89 59 39 71 29 K.K.Chopra

DOCUMENT No. A197-DR-6842-0002

REVISION No. 0

DATE 25-Mar-13

Page No.


Format no. 5-6842-1000-F3 Rev.3

INCLUDED

INCLUDED

INCLUDED PROJECT MANAGER

INCLUDED Dr. A.Nanda

INCLUDED

INCLUDED

INCLUDED

PROJECT : Strategic Storage of Crude Oil at Padur PH-II

COST ENGINEERING DEPARTMENT Under Ground Storage Facilities

Rs. LAKHS

TYPE OF ESTIMATE

Detailed

Conventional

Mar' 2013

Notes

TAXES & DUTIES

PROJECT :

EPCC COST SUMMARY ( ABOVE GROUND FACILITIES )

JOB NO. A197

SL. D E S C R I P T I O N CLIENT ISPRL

NO. LOCATION Padur

Fc Ic Sc TOTAL CAPACITY 2.5 MMT

LICENSOR

1 MAJOR ITEMS

1.1 VESSELS 66 1 60 2 27

1.2 HEAT EXCHANGERS 20 20

1.3 PUMPS & COMPRESSORS 69 11 2 57 71 69

1.4 FLARE, N2 Tank, EOT Cranes 6 16 15 6 31

1.5 AIR CONDITIONING/ PRESSURIZATION 1 22 26 1 48 EXECUTION METHODOLOGY

1.6 WATER FOR HOT OIL TESTING 50,000 M3 81 81

1.7 LPG FOR FLARE SYSTEM 20 MT 11 11

1.8 NITROGEN INERTIZATION 7 Million M3 18 90 18 90

1.9 BOILER 16 04 16 04 ESTIMATE VALIDITY

1.10 ETP 30 M3/hour 18 20 18 20

1.11 CP SYSTEM 18 18

NOTES

SUB-TOTAL (1)... 69 11 10 99 56 07 1 36 17

2 BULK MATERIALS 1 USD = Rs 54.75

2.1 PIPING 34 26 53 26 87 1 NOK = Rs 9.55

2.2 ELECTRICAL 18 04 18 04 1 EURO = Rs 71.28

2.3 INSTRUMENTATION 51 17 84 18 34

SUB-TOTAL (2)… 85 62 41 63 25

3 SPARES MANDATORY 1 55 2 81 4 37

4 CHEMICALS

SUB-TOTAL (1 TO 4)... 71 51 76 21 56 07 2 03 79

5 ERECTION

5.1 MECHANICAL 11 96 11 96

5.2 ELECTRICAL 2 71 2 71

5.3 INSTRUMENTATION 2 75 2 75

Custom Duty 25.85%

SUB-TOTAL (5)... 17 42 17 42 Excise Duty 12.36%

6 CIVIL STRL WORKS 82 55 82 55 CST w/o C Form 4.00%

7 INSULATION AND PAINTING WCT = 4.00%

SUB-TOTAL (1 TO 7)... 71 51 76 21 1 56 04 3 03 76 Service Tax= 4.94%

8 ESCALATION DURING IMPLEMENTATION PHASE 1 07 1 14 4 68 6 90

SUB-TOTAL (1 TO 8)... 72 59 77 35 1 60 72 3 10 66

9 INDIRECT COSTS

9.1 OCEAN FREIGHT 2 18 2 18

9.2 CUSTOMS DUTY 19 33 19 33

9.3 PORT HANDLING 73 73

9.4 INLAND TRANSPORTATION 4 50 4 50

9.5 EXCISE DUTY 9 56 9 56

9.6 CST w/o C form contractor 3 48 3 48

9.7 WORKS CONTRACT TAX 20 07 20 07 PROJECT MANAGER

9.8 SERVICE TAX 24 79 24 79

9.9 Karnataka works Welfare Tax 5 02 5 02

9.10 ENTRY TAX 6 79 6 79 PREPARED

9.11 INSURANCE 4 97 4 97 Satish Kumar/S.K.Kohli

SUB-TOTAL (9)... 2 18 49 35 49 87 1 01 40 REVIEWED

SUB-TOTAL (1 TO 9)... 74 76 1 26 70 2 10 59 4 12 06

10 Enabling facilities for EPCC contractor 4 12 1 85 5 98 APPROVED

11 HAZOP study 64 64 K.K.Chopra

12 Pre commissioning & commissioning 4 12 4 12

SUB-TOTAL (1 TO 11)... 74 76 1 34 94 2 13 09 4 22 80

13 DETAIL ENGG , PROJECT MANAGEMENT 21 14 21 14

14 CONTINGENCY 2 24 4 68 6 39 13 32 DOCUMENT No. A197-DR-6842-0002

15 FINANCING CHARGES 6 86 6 86 REVISION No. 0

16 PROVISION FOR LIABILITY 12 54 12 54 DATE 25-Mar-13

17 PROFITS 25 09 25 09 Page No.

T O T A L C O S T ... 77 01 2 05 25 2 19 48 5 01 74 FILE NAME

TAXES / DUTIES

Mar-13

Dr A Nanda

Ramesh Kumar

Bid Package Estimate

Strategic Storage of Crude Oil Project at Padur (Phase-II)


Rs. LAKHS

TYPE OF ESTIMATE

LSTK

PROJECT:


SL. D E S C R I P T I O N ALL COST IN RS. LAKHS JOB NO. A197

NO. CLIENT ISPRL

Fc Ic TOTAL LOCATION Padur

CAPACITY 2.5 MMT

1 PLANT & MACHINERY PRODUCT Crude Oil

1.1 SPM + OFFSHORE & ONSHORE PIPELINE + 253 92 482 22 736 13 S.P.M + 48", 20.1 Km

ONSHORE FACILITIES + 36", 10.3 Km

Prefeasibility

SUB-TOTAL (1)... 253 92 482 22 736 13

2 ENGINEERING COSTS ESTIMATE VALIDITY

2.1 DETAIL ENGG., PROCUREMENT, 55 21 55 21 Mar-13

CONSTRUCTION SUPERVISION &

PROJECT MANAGEMENT

2.2 SERVICE TAX @ 12.36 % 6 82 6 82 EXCHANGE RATES

1USD = Rs 54.75

1EUR = Rs 71.28

SUB-TOTAL (2)... 62 03 62 03 1NOK = Rs 9.55

3 SITE RELATED COSTS

3.1 LAND FOR TERMINALS/STATIONS EXCLUDED

3.2 TOWNSHIP EXCLUDED Custom Duty = 25.85%

3.3 INFRASTRUCTURE FACILITIES EXCLUDED Excise Duty = 12.36%

CST w/o C Form= 4.00% WCT= 4.00%

Service tax= 4.94%

SUB-TOTAL (3)... 4 OTHERS

4.1 OWNER'S CONST. PERIOD EXPENSES 2 00 5 99 7 98

4.2 START UP & COMMISSIONING EXPENSES 7 98 7 98

SUB-TOTAL (4)... 2 00 13 97 15 96Satish Kumar /

S.K.Kohli

SUB-TOTAL (1+2+3+4)... 255 91 558 22 814 13

Ramesh Kumar

5 CONTINGENCY 25 59 55 82 81 41

K.K.Chopra

SUB-TOTAL (1 TO 5)... 281 51 614 04 895 55 S U M M A R Y

6 WORKING CAPITAL MARGIN MONEY

SUB-TOTAL (1 TO 6)... 281 51 614 04 895 55 DOCUMENT NO. A197-DR-6842-0002

REVISION NO. 0

7 FINANCING CHARGES DATE : 25-Mar-13 PAGE :


Format no. 5-6842-1150-F1 Rev.1

Strategic Storage of Crude Oil Project at Padur (Phase-

II)

PROJECT COST SUMMARY

OVERALL PROJECT COST

TYPE OF ESTIMATE


LSTK

TAXES / DUTIES

PROJECT MANAGER

Dr. A. Nanda

PREPARED BY

REVIEWED BY

APPROVED BY

EXCL

EXCL


JOB NO.

CLIENT

NO. DESCRIPTION

A VARIABLE OPERATING COST

1 Power KWH 1 80 00 000 5 8 28

2 Diesel Litre 1 20 000 50.50 61

3 Nitrogen Nm3 6 00 000 44 2 64

4 Water m3 12 00 000 50 6 00

TOTAL VARIABLE COST (A) 17 53

B FIXED OPERATING COST

B.1 SALARIES & WAGES

1.1 EXECUTIVE PERSONS 13 20 00 000 2 60

1.2 NON EXECUTIVE PERSONS 18 10 00 000 1 80

B.2 COMPANY OVERHEADS

AS 35% OF B1 LS35% 1 54

B.3 REPAIR & MAINTENANCE

- @ 2.5% OF Plant & Machninery LS2.5% 12 54

- @ 0.5% of Bldg. & Civil Works LS0.5% 6 01

B.4 INSURANCE & TAXES

- @0.1% OF Capital Cost LS0.1% 2 23

TOTAL FIXED COST (B) 26 72

TOTAL OPERATING COST (A+B) 44 24

Format no. 5-6842-2000-F5 Rev.2

UNITS ANNUAL

QUANTITY

UNIT RATE

(Rs.)

AMOUNT

(in Rs. Lakhs)

ISPRL

A197

PROJECT Strategic Storage of Crude Oil at Padur PH-II

ANNUAL OPERATING COST



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14 RISK ANALYSIS

14.0 GENERAL

For the liquid hydrocarbons such as Crude Oil its flammability is considered to be the major risk. The inflammation of the mixture air-hydrocarbon can occur only within the inflammation range in the presence of an ignition source. Pollution is also considered as an unacceptable environmental hazard. It is therefore necessary to protect environment-sensitive areas and water resources.

14.1 HAZARD IDENTIFICATION

Based on the ongoing projects, an attempt has been made to identify possible hazards for the underground installation of the Padur storage project. The relevant causes of accidents leading to hazardous situation were analyzed and recorded in the hazard identification worksheets. An assessment of prevention measures has been also been outlined with an resultant process of determining the residual risk and the credible accident scenarios. Safety distances are evaluated in relation with the layout of the facilities, based on calculations performed for previous similar studies.

14.1.1 Methodology

The hazard identification study performed on this project is a review of the incidents, which could cause an accidental event leading to hazardous situation. Initial event choice is based on experience. A qualitative risk exposure assessment, before and after mitigation measures, has been allocated to each risk identified during the review as per the following tabulation:



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Severity 1 Very low Damage to equipment inside the facilities 2 Low Damage to equipment –

low injury to workers inside the facilities 3 Medium Equipment destruction –

injuries to workers inside the facilities 4 High Damage to equipment outside facilities / fatal accident inside

the facilities 5 Very high accident with heavy destruction / fatal accident outside the

facilities Probability 1 Very low Very unlikely to occur during the life of the facilities 2 Low Unlikely to occur more than one time during the life of the

facilities 3 Medium Likely to occur more than one times

during the life of the facilities 4 High Likely to occur more than one times

during the life of the facilities 5 Very high Very likely to occur several times

during the life of the facilities One has to stress the degree of uncertainty inherent to the assessment of the probability of occurrence of the initiating accidental events. This applies especially to the major accidents with a high or very high severity.



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14.1.2 Split of area

For the purpose of study, the facilities are split into different areas / sectors namely the following : • Aboveground filling and evacuation facilities • Wellhead equipments and operation shafts • Underground crude oil caverns

14.1.3. Selection of IAE (Initiating Accidental Events)

The principal IAE selected for this study are: • collision • dropped object • extreme weather conditions • vibrations • malice / terrorism • human error • plugging or blocking • corrosion • mechanical failure • fire • loss of utilities.

14.2. GENERAL MITIGATION MEASURES

Mitigation measures are taken to limit or prevent the occurrence of hazardous situations in the facilities. These measures are summarized in the following: • The design of the facilities is made in accordance with international and

national construction codes and standards. • Critical process parameters are permanently monitored, with alarms and/or

automatic shut-down sequence triggering in case of deviation. • The design of the facilities includes isolation systems in order to limit the

released inventory in case of leakage • A gas detection system is linked to an alarm system and to an automatic



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Emergency Shut Down system. Gas detectors will be located at each possible gas release area. All wiring to the detectors will be fire resistant.

• Fire detectors are designed to respond to one or more of the following symptoms: heat (thermal radiation), smoke and flame. All wiring to the detectors will be fire resistant. Fire detectors are located in all possible fire zones.

• Fire fighting system is designed for automatic and manual extinguishing of fires and for preventing oil spillage from emitting flammable gases.

• Spillage containment is designed to limit the surface of the pool in case of leakage

• Traffic is controlled in the plant • The facilities are protected from intrusion by a security fence, guards and

video cameras • Mechanical protection of the pipes is designed to prevent major failures due

to collisions. Inside the plant the main pipes will be laid underground • Suitable electrical material is installed for the different areas. • The control room and technical buildings are protected by gas detectors at air

inlets.



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15 RECOMMENDATIONS

A. Site-specific geotechnical investigation campaign could not be under taken due to the severe agitation by the local residents. The interpretative geological, hydro-geological and geotechnical model is prepared based on the available topographical, geological and geotechnical information collated from the near vicinity area, excavation-mapping data from the underground facilities being built under the phase I storage program. The topological and geological map is derived from the satellite imageries and field verification. Based on the aforesaid, it is recommended to perform site-specific topographic and geotechnical investigation during the basic engineering design stage.

B. The configuration of underground facilities including design basis for

underground storage caverns and proposed layout, associated process design including above ground plot plan, planning schedule and cost estimates have been worked out and presented. In addition, for connectivity from the storage facility to the nearest pipeline & proposed new SPM, a Pipeline Integration scheme has been presented.

C. Execution of the proposed storage facility would be dependent on the

following:

a) Firming up the mode of implementation either PPP, BOO, BOOT etc. b) Engagement of Owner’s Engineer / Project Management Consultant for

Pre-Project Activities and subsequent execution. c) Notification and Initiation of land acquisition process d) Performance of activities for statutory approvals such as EIA and RRA

D. Necessary discussion with local district is to be taken up for notification and

initiation of land acquisition process. This would be followed by necessary permission for sourcing water and electricity for the project facilities.

E. Concurrently, the process of carrying out Environment Impact Assessment

(EIA) and Rapid Risk Assessment (RRA) is required to be initiated. This would involve collection, study and assessment of the baseline data and further preparation of report.

F. In view of the integration requirements and the scheme of new SPM &

pipelines to be built, activities such as pipeline route survey including ROU corridor, preparation of pipeline route alignment sheets and basic design for the pipelines are to be taken up. This would enable to firm up a detailed cost estimate and project schedule for the Pipeline installation tender. It is therefore recommended Detail Feasibility Report (DFR) for SPM & Pipeline.



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detailed project report for phase ii of strategic...

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