drill and blast management plan - tina river hydropower

DRILL AND BLAST

MANAGEMENT PLAN SUBCONTRACTOR’S CI

TINA RIVER HYDROPOWER DEVELOPMENT PROJECT

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CONFIDENTIAL: THIS DOCUMENT IS CONFIDENTIAL AND MUST NOT BE COPIED OR REPRODUCED EXCEPT

WITH THE EXPRESS PERMISSION OF HYUNDAI ENGINEERING CO., LTD.

Drill and Blast Management Plan

Person Responsible HEC Construction Manager and

HEC HSE Manager

REV. DATE DESCRIPTION PREPARED CHECKED APPROVED

1 15/10/2019 Version 1 issued for Lenders’

Review HEC HEC

2 30/04/2020 Version 2 issued for OE’s Review HEC


Review – Access Road Lot 1 HEC

OE (JG) – Lot

1 only


review – Access Road HEC OE (JG)

5 03/11/2020 Version 3 resubmitted for

Lenders’ approval (Access Road) HEC OE (JG)

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Revision Log

Rev.

Date

(dd/mm/yyyy)

Revised Detail

Item Page Article Description

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CONTENTS

ACRONYMS 5

1 INTRODUCTION 6

1.1 PURPOSE AND SCOPE 6

1.2 PROJECT OVERVIEW 6

1.3 APPLICABLE STANDARDS 7

1.4 LINKS WITH OTHER PLANS 8

2 ROLES AND RESPONSIBILITIES 10

2.1 INTRODUCTION 10

2.2 SUBCONTRACTOR(S) 10

2.3 DESCRIPTION OF ROLES AND RESPONSIBILITIES 11

3 RISK ASSESSMENT AND MANAGEMENT 14

4 DRILLING AND BLASTING MANAGEMENT 21

4.1 EXPECTED DRILLING AND BLASTING AREA 21

4.2 SELECTION OF BLASTING PATTERNS 23

4.3 BLASTING PATTERNS AND SPECIFICATIONS 25

4.4 DRILLING AND BLASTING PROCEDURE 27

4.5 NOISE AND VIBRATION MANAGEMENT FOR BLASTING 29

4.6 NOISE AND VIBRATION MEASUREMENT INSTRUMENT 30

4.7 BLASTING AND DRILLING PERMIT PROCESS 31

5 REPORTING AND AUDITING 33

5.1 REPORTING 33

5.2 AUDITING 34

ANNEX A- DRILLING ACTIVITY DURING GEOTECHNICAL INVESTIGATION AND WELL

DEVELOPMENT 36

ANNEX B- DRILLING AND BLASTING PLAN 39

ANNEX C – WELL DRILLING PLAN 40

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ANNEX D- DRILLING METHOD STATEMENT 41

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ACRONYMS

Name Description BOOT Build, Own, Operate and Transfer CESMP Construction ESMP Framework DBMP Drill and Blast Management Plan EPC Engineering, Procurement and Construction EIS Environmental Impact Statement E&S Environmental and Social ESIA Environmental and Social Impact Assessment ESMP Environmental and Social Management Plan ESS Environmental and Social Safeguard HEC Hyundai Engineering Co. Ltd. HSE Health, Safety and Environmental GIIP Good International Industry Practice IA Implementation Agreement IFC International Finance Corporation IFC PS IFC Performance Standard KW Korea Water Resources Corporation LTA Lenders Technical Advisor MASL Meters above sea level MMERE Ministry of Mines, Energy and Rural Electrification OE Owner’s Engineer PPA Power Purchase Agreement PPE Personal Protective Equipment RCC Roller Compacted Concrete SIEA Solomon Islands Electricity Authority SIG Solomon Islands Government THL Tina Hydropower Limited TRHDP Tina River Hydropower Development Project TSS Total Suspended Solids

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1 INTRODUCTION

The Tina River Hydropower Development Project (TRHDP or “Project”) is a hydropower development located on central Guadalcanal in the Solomon Islands, managed by a dedicated Project Office (PO) under the national Ministry of Mines, Energy and Rural Electrification (MMERE).

Tina Hydropower Limited (THL) was established by Korea Water Resources Corporation (KW) and Hyundai Engineering Company (HEC). THL will Build, Own, Operate and Transfer (BOOT) the Project under an Implementation Agreement (IA) with the Solomon Islands Government (SIG) and a Power Purchase Agreement (PPA) with Solomon Islands Electricity Authority (SIEA) The BOOT concession is expected to last for a 30-year period, following commissioning.

HEC will be responsible for the Engineering, Procurement and Construction (EPC) of the Project, while KW will be responsible for the Operation and Maintenance contract. THL will sell electricity to the Solomon Islands Electricity Authority (SIEA), the state-owned power utility, for the duration of the concession. At the end of the concession, the hydropower infrastructure will be transferred to the SIG or SIEA.

1.1 PURPOSE AND SCOPE

The purpose of this Drill and Blast Management Plan (DBMP) is to set out the approach to manage and mitigate the impacts of drilling and blasting over which HEC have control, as identified in Chapter 9 of the Project’s Environmental and Social Impact Assessment (ESIA) and HEC’s Worker’s Health and Safety Plan (HEC-CDSB-CESMP-PPP-008).

It should be noted the information in this DBMP is based on relevant regulations, guidelines and standards at the time of writing of the ESIA (August 2017) and the updated EIS Study, dated May 2019. Should the Project activities change or new regulations, guidelines or standards apply, HEC will review and amend this DBMP. These changes shall be reviewed by THL and OE, and subject to the "management of change" protocol in P1-CESMP.

1.2 PROJECT OVERVIEW

The Project consists of a 53 meter high Roller Compacted Concrete (RCC) dam (from riverbed to dam crest) in an uninhabited area of Malango Ward located 20km southeast of Honiara at an elevation of approximately 122 meters above sea level (MASL) and roughly 30 river km from the sea. It also incorporates a 3.3 km tunnel to a powerhouse and a tailrace at elevation 73 MASL. The reservoir formed by the dam will extend upstream approximately 2.6 km and will have a surface area of about 0.28 km2

at an elevation of 175 MASL. The powerhouse will be located 5.4 km downstream from

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the dam on the left bank of the Tina River, and water will be diverted to the powerhouse from the reservoir through the underground tunnel. Initially, the powerhouse will have 3 turbine/generator units, each with a capacity of 5 MW, allowing a maximum discharge of about 18 m3/s and a minimum discharge of 2.4 m3/s. An environmental flow of 1 m3/s will be maintained between the dam and the powerhouse tailrace, a distance of 5.7 km.

A variety of drilling methods were examined, including the use of pneumatic and hydraulic drills, in which hydraulic drills were chosen due to their lower noise profile. Standard blasting methods were chosen since, for the most part, blasting will occur two or more kilometres from the nearest settlements. Notwithstanding, for safety purposes, blasting mats will be employed to minimise the spread of shot rock from the blasts

1.3 APPLICABLE STANDARDS

The framework of the DBMP has been developed with due regard to relevant legal requirements, National Standards and World Bank Performance Standards and other international standards. The framework includes laws and requirements to which all relevant parties will adhere from the commencement of the Project through the completion of the rehabilitation works and decommissioning activities.

Should new regulations, guidelines or standards apply; HEC will review, amend this DBMP.

The references, documents and applicable standard related to drilling and blasting activities during construction are noted in the following sections.

HEC Standard

The following HEC standards apply to drilling and blasting management:

• Risk Assessment Procedure (HEC-AH-H04-H03);

• HEC-AH-H04-H34, Control of Substance Hazardous to Health;

• HSE Management of Subcontractors (HEC-AH-H04-H02 HSE);

• Training and Awareness Procedure (HEC-AH-H04-H05 HSE);

• HSE Monitoring and Measurements Procedure (HEC-AH-H04-H09).

National Laws and Regulations

The following legislative texts apply to drilling and blasting management.

• Solomon Islands Safety at Work Act 1982;

• Solomon Islands Explosive Act 1968;

• Solomon Islands Environment Act 1998 and Environment Regulation 2008;

• Solomon Islands Labour Act 1996;

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• Solomon Islands Provincial Government Act 1997;

• Solomon Islands Public Health Ordinance 1970;

• Solomon Islands Environmental Health Act 1980 and Environmental Health (Public Health Act 1970) Regulations.

International policies, standards, and Standards

The following international standards apply to drilling and blasting management:

• Pollution Protocol for Emergencies (Ratified 10/9/98);

• World Bank Environmental and Social Performance Standard 1: Assessment and Management of Environmental and Social Risks and Impacts;

• World Bank Environmental and Social Performance Standard 2: Labour and Working Conditions;

• World Bank Environmental and Social Performance Standard 3: Resource Efficiency and Pollution Prevention;

• World Bank Environmental and Social Performance Standard 4: Community Health, Safety, and Security;

• World Bank Group’s General EHS Guidelines: Construction and Decommissioning (April 2007);

• The World Bank Environmental and Social Framework, World Bank, 2016;

• Asian Development Bank Safeguard Policy Statement (June 2009) Appendix 1, Safeguard Requirement 1: Environment;

• International Finance Corporation (IFC) Performance Standards (2012); and

• Economic Development Cooperation Fund (EDCF) Safeguard Policy (2016).

Where both national and international standards are applicable, the Project will apply the most stringent standard.

1.4 LINKS WITH OTHER PLANS

There are a number of other management plans that are associated with the NVMP

(Table 1.1). HEC has a comprehensive set of internal HSE procedures which will be

implemented on site. For the purpose of the TRHDP, where there is any conflict

between the mitigation measures and management approaches described in ESMPs,

the TRHDP ESMP requirements will take precedence over HEC internal procedures.

Table 1-1: Links to other management plans.

Management Plan Description

Construction Environmental and Social

Management Plan (CESMP; P1)

Refer to this plan for presentation of

organizational charts, detailed description of

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Management Plan Description the audit process, description of process to

amend the management plans.

Grievance Redress Mechanism

(GRM; P6)

Refer to this plan for management of

grievances raised during the construction

period.

Worker’s Health and Safety Plan (WHSP;

P8)


worker’s health and safety

Worker’s Code of Conduct

(WCC; P9)

Refer to this plan for mitigation measures

related to worker’s code of conduct.

Biodiversity Management Plan (BMP; P2) Refer to this plan for mitigation measures to

limit impacts towards biodiversity.

Quarry Management Plan

(QMP; C5)

Refer to this plan for the mitigation strategies

for managing quarry activities.

Security Management Plan

(SMP; P7)

Refer to this plan for management of security

Hazardous Materials Management Plan

(HMMP; P13)


hazardous material.

Spill Prevention and Emergency Response

Plan

(SPERP; P14)

Refer to this plan for procedure to follow in

the event of a spill of hazardous material and

how to prevent it.

Post Construction Rehabilitation and

Revegetation Plan

(PCRRP; C4)

Refer to this plan for the strategies to follow

to rehabilitate cleared forest areas.

Air Quality Management and Dust Control

Plan

(AQMDCP; P15)

Refer to this plan for management of air

quality and dust control.

Noise and Vibration Management Plan

(NVMP; C13)

Refer to this plan for management of noise

and vibration.

Construction Works Monitoring Plan

(CWMP; M6)

Refer to this plan for the procedures to follow

when monitoring working activities.

Water Quality Monitoring Plan

(WQMP; M2)


when monitoring water quality.

Air Quality and Noise Monitoring Plan

(AQNMP; M7)


when monitoring air and noise impacts.

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2 ROLES AND RESPONSIBILITIES

2.1 INTRODUCTION

Having an appropriate organizational structure in place, with all people having defined roles and responsibilities, is essential to ensuring the overall success of this DBMP. This section provides details of HEC’s organizational structure with regards to onsite delivery of the Project, and the various roles and responsibilities of those people in relation to delivering the Project Proponent’s EHS expectations, including meeting the requirements of the Construction Health, Safety and Environment Management Plan.

HEC has established this DBMP in accordance with the applicable standards. HEC will manage their contractors and suppliers in accordance with this DBMP and liaise with the appropriate personnel to ensure compliance with the overall aims of HEC’s CESMP (CESMP; P1)

2.2 SUBCONTRACTOR(S)

Each subcontractor will be responsible for the execution of the DBMP as applicable to their role in the project. It will be a requirement for the subcontractor to demonstrate to HEC as part of the tendering process the way their role in the plan will be implemented. Such actions will then become a contractual commitment between the subcontractor and HEC.

HEC will hire subcontractors that are reputable and legitimate enterprises appropriately trained in drill and blast management, and comply with the HSE Management of Subcontractors (HEC-AH-H04-H02). Monitoring and auditing will be carried out according to this DBMP, as well as the HSE Management of Subcontractors (HEC-AH-H04-H02), to ensure subcontractors are compliant.

The drilling and blasting subcontractor/s should furthermore hold valid licences and be certified in the work they have been contracted to do.

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2.3 DESCRIPTION OF ROLES AND RESPONSIBILITIES

HEC has committed to providing the necessary human resources to ensure that the organizational structure noted above can work to implement this DBMP and achieve compliance with all relevant standards. A description of the key positions and their responsibilities are provided in Table 2-1.

Table 2-1: Key Roles and Responsibilities

Position Responsibilities

HEC Project Manager (Mr Eu Man Moon)

• Ensure that adequate resources are established to successfully implement this DBMP.

• Ensure that all HEC project managers and subcontractors understand and fulfil their NVMP responsibilities

• Respond to monitoring findings and ensure implementation of remedial works as required

HEC Construction Manager (Mr Yoo Jae Bong)

• Responsible for the implementation and control of the DBMP.

• Ensure that the HEC HQ Design Team integrates E&S mitigation measures into the final project design.

• Participate in site inspections to plan and confirm the detailed design of E&S site measures.

• Review and approve detailed site plans and method statements incorporating E&S measures.

• Ensure that all personnel involved in construction activities, including subcontractors and vendors, are adequately trained and informed on the requirements of the DBMP.

• Participate in site inspections in the early stages of works at each site with the HEC HSE Manager, subcontractors and THL.

• Review and approve HSE reports.

• Audit subcontractor performance.

• Ensure project design includes drill and blast management measures.

HEC HSE Manager (Mr Dae Yong Kim)

• Ensure that all personnel including subcontractors and vendors are adequately trained and informed on the requirements of this DBMP.

• Lead site inspections with the HEC Construction Manager to plan and confirm the detailed design of E&S site measures.

• Prepare detailed site plans integrating E&S measures into final design drawings and method statements and submit these to the HEC Construction Manager.

• Lead weekly site inspections with subcontractors and THL during construction.

• Prepare weekly and incident HSE Performance Reports.

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• Audit subcontractor E&S performance. HEC E&S Team • Inspection of site to ensure compliance with DBMP.

• Managing of workers health, such as listener fatigue.

• Preparation of weekly HSE performance report. HEC Emergency Supervisor

• Manage emergency control operations related to drill and blasting activities

HEC Emergency Response Team

• Support emergency response operation according to the Spill Prevention and Emergency Response Plan (HEC-CDSB-CESMP-PPP-014)

HEC Training Supervisor

• Provide appropriate training and assessment to all parties involved in drilling and blasting activities

• Encourage safety promotions and employees suggestions to improve safety performance and practice.

HEC Administration Manager & Team

• Managing of grievance mechanisms regarding noise and vibration levels

Subcontractors - Sungpoong

• Implementation of mitigation measures as per DBMP

• Prepare Method Statement and Risk Assessment for Permit to Work

Security Subcontractor (BEEDS Security Services)

• Maintain security of the storage bunker and prevent unauthorised access.

THL E&S Manager (to be confirmed; currently Mr Jihun Lee, CFO is primary contact)

• Review DBMP compliance with the E&S Standards and GIIP.

• Participate in daily site inspections in the early stages of works at each site with HEC and subcontractors.

• Participate in weekly site inspections with HEC and subcontractors during construction (following early works).

• Prepare monthly E&S performance reports, advising HEC of any non-conformances and required corrective actions.

• Audit HEC compliance with the DBMP. Owners Engineer (OE) – Stantec New Zealand

• Review DBMP for compliance with the E&S Standards and GIIP

• Monitor and audit project delivery and HEC activities in accordance with the detailed project design, method statements, DBMP, related MPs, and detailed site plans.

• OE Site Engineer (Vilive Anise and/or William Waddell) will undertake regular site supervision, and report any E&S non-compliances to the HEC HSE Manager, THL E&S Manager and OE Environmental & Social Safeguards (ESS) Lead (Jessica Grinter – Off Shore).

• Audit HEC performance with respect to the requirements of the EPC Contract, and health, safety, environmental and social obligations (including but not limited to the E&S Standards, and Schedule 7 of the EPC Contract). Auditing will include a site visit conducted every six months from commencement of

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construction, for the duration of the construction phase, by the OE ESS Lead at minimum.

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3 RISK ASSESSMENT AND MANAGEMENT

A risk assessment was conducted to identify the project activities which might present

a hazard or risk relating to drilling and blasting, and assess the potential impacts which

may arise. A range of mitigation measures and management approaches were then

identified, to achieve a reduction in the initial perceived risk. The objective in

implementing these measures and approaches is to reduce the level of residual risk to

a lower (and acceptable) level.

The following tasks were undertaken to analyse and evaluate risks and identify

potential impacts:

• Identify all activities and sub-activities associated with construction of

the Project;

• Assess the likely impact of the activity on the environment, safety and

security of workers and the public, and social/cultural aspects of the

Project setting;

• Determine the possible consequences if each impact were to occur;

• Assess the likelihood of each impact occurring in the absence of any

controls;

• Consider the severity of impact/s;

• Determine a risk level based on a 5 X 5 risk assessment matrix.

• Document current and future mitigation measures that need to be

implemented to bring the level of risk down to an acceptable level

(including consideration of the findings of the Environmental and Social

Impact Assessments (ESIAs) dated August 2017 and July 2019); and

• Re-evaluate to determine the residual risks once the mitigation

measures have been implemented.

HEC and THL applied a modified version of the Risk Ranking Table from the IFC EHS Guidelines (Table 2.1.1) to assess the environmental, health and safety, security and social risks which could be encountered due to construction activities. The matrix applied is presented in Table 3-1 below.

The initial risks identified for each activity; associated impacts, and residual risks (after

implementation of mitigation measures) have been captured in a ‘live’ risk register,

which is maintained on ProjectSpace, the online document management system

administered by HEC for the Project. The activities, risks and impacts presented in

ESMPs are consistent with those listed in the register. The register will be used by HEC,

THL and the OE as a tool to monitor the effectiveness of mitigation measures in

reducing risk across the Project, and will be regularly reviewed and updated as the

Project progresses. The subcontractor to be appointed to do the required drilling

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and/or blasting needs to adhere to the Risk Assessment done in this DBMP. If they wish

to use their own risk assessment, it needs to be approved by OE and THL prior to

commencing any work.

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Table 3-1 5 X 5 Risk Assessment Matrix

Likelihood Consequences

Insignificant

Negligible impacts to a minimal area

of low environmental

or social significance, managed by

internal control

procedures

Minor

Minor or minimal short-term impacts

to the environment

and social areas

Moderate

Significant impacts to the

wider environment

or social areas, where short-term restoration works are

needed

Major

Major, persistent

and/or extensive

impacts to the environment

or social areas where longer

term remediation is required (> 6

months)

Catastrophic

Catastrophic and

irreversible environmental

damage to social areas or environment

A. Almost certain

Very high likelihood

the risk will occur

(>75%)

Moderate High Extreme Extreme Extreme

B. Likely

High likelihood

the risk will occur

(51 - 75%)

Moderate High High Extreme Extreme

C. Possible

Medium likelihood

the risk will occur

(21 - 50%)

Low Moderate High High Extreme

D. Unlikely

Low likelihood

the risk will occur

(5 - 20%)

Low Moderate Moderate High High

E. Rare

Very low likelihood

Low Low Low Moderate Moderate

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the risk will occur

(<5%)

Mitigation measures were selected to achieve the following:

• In the cases where risk level was assessed as a Moderate or High –

reduce risk to Low;

• In the cases where risk level was assessed as Low – ensure risk level

does not increase; and

• In the cases where risk level was assessed as Extreme – modify the

project to avoid critical risk activities.

The impacts associated with construction of the Project, and particularly in relation to

the scope of this Plan, are included in Table 3-2, along with assigned mitigation

measures / management approaches. The table also outlines the monitoring actions

that will be applied to continually evaluate the effectiveness of these measures and

approaches for the duration of construction.

As noted in Section 1.4, this DBMP has links to several other plans. In particular, Table

3-2 below cross-references measures from (and should be read and implemented in

conjunction with):

• Hazardous Materials Management Plan (HMMP; P13)

• Spill Prevention and Emergency Response Plan (SPERP; P14)

• Air Quality Management and Dust Control Plan (AQMDCP; P15)

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Table 3-2 Mitigation / Management and Monitoring Procedures

# Project Activity/Impact Management Monitoring & Reporting

Mitigation Measure Responsibility / Timing Monitoring & Reporting Activity Responsibility / Timing

1. Local communities could be left out of project management decisions that may affect them

• Project affected communities are consulted on the planned construction activities, including options for location of major cuttings that would require blasting (for example). This consultation is undertaken well in advance of detailed design by Community Liaison Officers employed by HEC, so that communities have chance to have a say in Project design/outcomes. Engagement is done as part of the pre-construction activities outlined in the Stakeholder Engagement and Communication Plan (SECP; P3).

HEC, THL

During basic design; pre-construction

Engagement activities are captured in the Stakeholder Engagement Database by the THL E&S Manager (in consultation with HEC HSE Manager and E&S Staff (Social)).

Any grievances lodged regarding proposed blasting activities are recorded in the Project grievance register and managed according to the GRM (P6).

HEC HSE Manager, HEC Construction Manager,

THL E&S Manager

HEC CLOs and THL E&S Assistant (Social) (grievance management)

2. Obtaining environmental permits for project-related activities (HEC submits applications)

• Obtain the relevant permits required under Solomon Islands law for the importation, storage and use of explosives, and for drilling and blasting activities (in accordance with Section 1.3 and Section 4.7 of this DBMP)

Prior to start of each construction phase (e.g. Access Road, main dam)

Copies of permits are kept on Project Space; any related designs/ specifications/ assessments prepared for the permits (e.g. magazine specification and as-built plans) are subject to review by THL and the OE (and where applicable, approval by PO or Lenders).


THL E&S Manager

HEC CLOs and THL E&S Assistant (Social) (grievance management)

3. Construction noise, dust, fumes etc from road construction activities

• Develop a Drilling and Blasting Management Plan (this DBMP) and detailed and specific blasting plans for distinct activities within the construction schedule, while basic design and detailed design reviews are underway.

• Safeguards requirements for drilling and blasting detailed in the ESIA and in the DBMP must be considered in design.

• Blasting and drilling equipment will be equipped with silenced masts, which can reduce noise levels by up to 10dBA.

HEC

Prior to approval of detailed design

Engineering design check and review by HEC Design Engineers and HEC Construction Manager; safeguards review by THL and the OE.

HEC Construction Manager, HEC HSE Manager

THL E&S Manager

OE (review) – prior to construction

4. Drilling into groundwater aquifer which may also be used by others (downgradient); could be slow to replenish

• Design and use of the deep well must be reviewed by THL and the OE and approved by Lenders prior to any extraction.

• Water abstraction permits need to be obtained from SIG prior to any commissioning of deep wells.

• Bentonite paste need to be grouted into excavation hole to prevent the water infiltration from/to the soil aquifer and surface inflowing water into rock aquifer

• Set an inclined slope around the well to prevent ingress of any polluted site drainage

• Discharging pipe needs to be installed in 30cm above elevation from the ground surface and bent 90 degrees to horizontal direction in order to prevent inflowing of polluted water. Construct shelter over deep well pump station to prevent ingress of site drainage/flooding after heavy rainfall.

• Inspect initial water quality, conduct pump tests to understand characteristics of aquifer. Establish a plan to regularly monitor water quality within the well.

HEC to implement and check subcontractor / construction phase

Prior to operation of camp (or commissioning of well)

• Training records and certification of subcontractor regarding drilling capabilities

• Well drilling permits

• Water abstraction permits

• Monitor and report water abstraction and bore integrity/safety to ensure compliance with regulations and relevant water quality standards.

HEC Environmental and social team to monitor and report / weekly

HEC HSE Manager will aggregate and report findings in HEC’s monthly report to THL

THL aggregates into Quarterly safeguards report

5.

Vibration generated by drilling equipment

• Prepare Drilling and Blasting Plan (Annex B);

• Select methods to reduce noise and vibration;

• Use Hydraulic instead of pneumatic drills;

• Equipment to be equipped with engine exhaust silencers / mufflers;

• Use blasting mats to reduce noise, fly rock and dust;

• HEC will adopt optimised blasting techniques in confined areas (inside the tunnels);

• HEC to implement mitigation measures / Construction phase

• Daily inspection of drilling/blasting activities by HEC HSE Team

• Monitor and assess noise and vibration during drilling and blasting activities to ensure compliance with regulations.

• Training records and certification of subcontractors


THL E&S Manager


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• The quantity of blasting materials will be carefully controlled according to the real situation requirements to avoid unnecessary breakage of rock mass.

• The number of artificial lights, and light intensity will be kept to a minimum, while still maintaining a safe working environment. The lights will be oriented toward the ground to avoid disorienting bats in flight.

• Limit activities to daylight hours whenever possible.

• State of the art drilling machines provided with dust extraction system will be used. In the event that a dust extraction system is not available, water spraying will be used to prevent airborne dust. Dust controls will be implemented in accordance with the Air Quality Management and Dust Control Plan (AQMDCP; P15).

• Safety observations, near misses and incidents reported in relation to drilling activities

6. Potential misfiring of explosives/loss of control. Potential major injury to workers. Damage to property.

Ignition/fire potentially causing explosion. Potential misfiring of explosives/loss of control. Potential major injury to workers. Damage to property.

Falling rocks could cause major injury to workers and property, and also damage flora and fauna. Damage to vehicles.

• Notify local communities before blasting, in accordance with the SECP (P3).

• HEC will ensure that any unauthorized persons will be located a safe distance away from the blasting point. The area will be patrolled by security guards (as per Security Management Plan; P7). The communications protocol described in Section 4.4 of this DBMP will be strictly followed.

• Before the detonation takes place, HEC will check that there are no people inside the controlled area and maintain the exclusion during the blasting and mopping up afterwards.

• An authorised representative from RSIPF needs to present on the day of blasting to ensure

- all permits are in place

- all appropriate measures have been taken as stipulated within the Drilling and Blasting Management Plan (Annex B)

- all relative mitigations detailed in the WHSP (P8) and SPERP (P14) have been considered and implemented (this should be shown on a completed Job Hazard Analysis form as per the WHSP).

• Proper dewatering and ground stabilisation needs to be in place during drilling procedures. Only qualified and authorized personnel will handle explosives and manage the blasting process.

• Appropriate PPE in accordance with the Workers Health and Safety Plan (P8) needs to be provided to all personnel handling explosives and managing the blasting process, such as hearing, hand and eye protection, fire proof vests, high visibility clothing, etc.

• Workers operating in the blasting area will use hearing protection sufficient to reduce noise by at least 30 dB to a limit of 75 dB (as per Annex B). best protection will be achieved by using a combination of Class 4 and Class 5 hearing protection (e.g. ear buds and over-ear muffs).

• The HEC supervisor on duty and at least two of the personnel working in the blasting area (laying charges etc), will wear hearing protection with radio connection (i.e. electronic ear muffs with link to two-way radio system). However, no person shall transmit radio while handling detonators.

• Proper communication protocol be in place in accordance with the Spill Prevention and Emergency Response Plan (SPERP; P14) communication procedures.

• If there has been a failure in the blasting operation, only competent personnel may be allowed on site to do the work necessary to detonate the explosive, or completely redo the blasting.

• Specific training on explosive handling and safety management will be provided to the personnel appointed in magazine area.

• An internal HEC procedure will be used for authorization to proceed for each blasting activity.

• HEC to prepare plan / pre-construction

• HEC to implement mitigation measures / Construction phase

HEC Supervisor to coordinate training activities / during blasting

• Daily inspection of blasting activities by HEC HSE Team

• Training records and certification of subcontractor regarding blasting capabilities Monitor and assess noise and vibration during drilling and blasting activities to ensure compliance with regulations.

• Safety observations, near misses and incidents reported in relation to drilling activities (and records of corrective actions applied)


THL E&S Manager

THL to Audit HEC / every three months;




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7. Storage and use of explosive materials on an active construction site

• The transportation, storage, processing, packaging on site, blasting and the disposal of the blasting material will comply with Solomon regulations on the use of explosives.

• HEC will provide appropriate and effective firefighting system at the storage bunker on-site.

• HEC will provide training on safety handling of explosive material and emergency procedures to all HEC personnel and subcontractors’ personnel.

• Vehicles carrying explosives will not be left unattended and will be parked only in designated parking areas.

• Vehicle drivers will comply with the specific laws related to the materials being transported.

• Vehicles carrying explosives will avoid congested areas to the maximum extent possible.

• SIG will coordinate security management with the Royal Solomon Islands Police Force prior to explosives transport.

• Transfer of explosive will be registered according to Hazardous Materials Management Plan (HMMP; P13)

• The HEC Project Manager will approve a separate secure “bunkered” facility for storing explosives (magazine)

• Explosives will be stored in an above ground magazine located close to sites where they will be used.

• The storage of explosive material in the on-site magazine will be limited to one week supply

• The explosives magazine will be kept locked, with access limited to authorized staff.

• A log-book will be kept at the magazine to register the movement of explosives (i.e. deliverer or user, quantity, date; following a similar format to Annex B of the HMMP)

• Explosive boxes will be clearly labelled with an “explosive sign”.

• SIG will responsible for the transport of explosive material / during the transportation

• HEC will be responsible for the storage on site / during construction

• Weekly Inspection of firefighting system

• Weekly inspection of magazine storage facility

• Training records and certification of subcontractors

• SIG’s involvement for security management

• Project manager’s approval for separate secure “bunkered” facility

• Security of explosive bunker

• Register of the movement of explosives

• Safety observations, near misses and incidents reported in relation to drilling activities (and records of corrective actions applied)


THL E&S Manager

THL to Audit HEC / every three months


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4 DRILLING AND BLASTING MANAGEMENT

The following content is supplementary, to inform implementation of the mitigation

measures summarised in Table 3-2 above. Implementation of the DBMP will be

monitored throughout the construction phase of the Project, to ensure that the

desired outcomes are being achieved. Monitoring and reporting criteria, for each

management measure, are outlined in Table 3-2 above. A summary of reporting and

auditing requirements is included in Section 5.

4.1 EXPECTED DRILLING AND BLASTING AREA

Table 4-1 below shows the expected blasting area and distance from surrounding

houses. Also refer to the Drilling and Blasting Plan in Annex B and the Drilling Method

Statement in Annex D.

Table 4-1 Drilling and blasting area (estimated)

Item Blasting Area Surrounding

houses and villages

Access Road

Lot 2-2 2,200 m

Lot 2-3 2,800 m

Lot 3-1 370 m

Powerhouse Powerhouse 360 m

Tunnel Surge Shaft 520 m

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Figure 5.1: Status of adjacent houses in the blasting area

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Figure 4-1 Proposed locations of four deep wells

4.2 SELECTION OF BLASTING PATTERNS

Table 4-2 and Table 4-3 show the amount of gunpowder by blasting pattern and

distance, and Table 5.4 shows the blasting pattern for each area.

Table 4-2 Blasting patterns

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Table 4-3 Amount of gunpowder by speed and distance of vibration

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Table 5.4: Planned blasting pattern for each area

Item Blasting Area Surrounding houses and

villages Blasting Pattern

Access Road

Lot 2-2 2,200 m Large scale blasting

Lot 2-3 2,800 m Large scale blasting

Lot 3-1 370 m Large scale blasting

Powerhouse Powerhouse 360 m Large scale blasting

Tunnel Surge Shaft 520 m Precise vibration control blasting

4.3 BLASTING PATTERNS AND SPECIFICATIONS

Blasting pattern was selected considering the following site conditions.

• Large scale blasting has been selected because the blasting area is further than

300m away from nearby houses

• When it comes to Surge Shaft works during tunnelling works, precise vibration

control blasting method or a breaker will be used considering over-break

• Final blasting pattern will be selected by test blasting before first blasting

works

Table 4-4 and Figure 4-2 show the blasting specifications and cross sections

respectively.

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Table 4-4 Blasting specifications

Classification Precise vibration control

blasting Large scale

blasting

Drilling machine Crawler Drill Crawler Drill

Drilling method 70~90˚ 70~90˚

Size of drilling hole(mm) 45 75

Drilling length(m) 2.0 8.7

Minimum burden(m) 0.8 3.0

Interval of drilling hole(m) 1.0 3.5

Figure 4-2 Estimated floor plan

Calculation of drilling amount per day

• Drilling length (H) : 8.7m, Drilling speed(V1) : 0.4m/min (Efficiency of moderate

rock : 90%)

Drawing speed(V2) : 4m/min , Rod connection(t2) : 2min, Move and

installation(t3) : 3min

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Cm = (H/V1) + (H/V2) + t2 + t3 = 28.9min / hole

∴ Drilling amount per day= 60min / 28.9min /hole× 8hr = 16holes

Calculation of blasting amount per day

• Drilling length (H) : 8.7m, Burden(W) : 3.0m, Interval of hole(S) : 3.5m, The

number of holes : 16 holes

Q = 9.0 * 17.5 * 8.7 = 1,370m3 / day

4.4 DRILLING AND BLASTING PROCEDURE

The procedure for drilling and blasting proceeds as shown in the flow chart in Figure

5.3. More detail can be found in the Drilling and Blasting Management Plan in Annex

B and the Drilling Method Statement in Annex D.

Figure 4-3 Drilling and blasting procedure flow chart

Communications protocol

The RSIPF will be notified at least 24 hours prior to any blasting activity, by the HEC

HSE Manager. HEC will also notify surrounding communities in advance of such

activities, providing at least 24 hours’ notice, and using protocols in accordance with

the Stakeholder Engagement and Communications Plan (SECP; P3). This will include an

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explanation of the warning signals for blasting, expected duration of the activity, and

temporarily restricted access to the area.

Lines of communication will be maintained both visually and verbally/audibly between

drilling and blasting personnel (e.g. specialist personnel laying charges, completing

checks) throughout the entire procedure.

All personnel involved in drilling and blasting will have a two-way radio on their person

at all times, and all radio equipment will be intrinsically safe to prevent any accidental

ignition. Personnel will remove any other potential ignition sources (e.g. mobile

phones, lighters, static-creating materials) from their person before entering the work

area.

Prior to laying of charges, the blasting area will be cleared with a 250 metre radius by

security personnel.

In accordance with the Solomon Islands Explosives Act 1968, red flags (no less than 3’

x 2’ (915 mm x 610 mm) in size) will be placed on all roads, tracks and footpaths leading

to the blasting area at a safe distance from the site of blasting, having regard to the

amount and nature of explosives being used. Based upon Annex B, this distance will

be 250 metres at minimum from the blasting site.

Signs will be placed alongside the flags; these will consist of boards with the wording

“DANGER BLASTING” in red block capitals on a white background. Lettering will be at

least 4” (102mm) high. At key locations where any workers or members of the public

may enter, additional signs will be placed to notify details of the blasting activity

including details of the three-step siren warning; scheduled start and finish times for

blasting, and the contact number (and radio frequency) for the appropriately qualified

HEC Supervisor on duty at the blasting location. The signs will display warnings and

prohibit people from entering the area. Security personnel will secure access to the

blasting area for the duration of blasting.

A three-step siren system will be used prior to blasting, to warn workers and any

members of the public nearby, as follows:

1. 5 minutes prior to blast: WARNING SIGNAL(series of long siren blasts, lasting

1 minute)

2. 1 minute prior to blast: BLAST SIGNAL (series of short siren blasts, lasting 1

minute)

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BLAST (at least two people will count the shots. If there is any doubt as to

whether all shots were fired, a delay of at least 30 minutes will be observed

before any personnel re-enter the blasting area).

3. ALL CLEAR SIGNAL: sounded once all shots have been fired and an inspection

has found the blast area to be safe.

In no case shall the blasting area be left unsupervised, until it has been examined and

found to be safe. Once blasting is complete and the area is made safe, all flags and

signs will be removed.

4.5 NOISE AND VIBRATION MANAGEMENT FOR BLASTING

The regulatory criteria for blasting vibration and noise are shown in Tables 5.6 and 5.7

Table 4-5 Regulation of blasting vibration

Item Culture Heritage Building Store Factory

Vibration (cm/s)

0.2 0.3 ~ 0.5 1.0 1.0 ~ 5.0

Table 4-6 Regulation of blasting noise

Item Human Being Animals

Noise (dB)

75 70

Among the research data on the impact of noise on wild animals, Table 5.8 shows the

animals that live in the construction area. Consideration has also been given to native

fauna which may be sensitive to noise and vibration such as cuscus, native bats and

forest birds (as described in the Noise and Vibration Management Plan; C13), however

sensitivity data is not included for those particular species. The mitigation measures in

Table 3-2 along with measures outlined in the Forest Clearance Plan (C3; such as

wildlife shepherding) and Biodiversity Management Plan (BMP; P2) will also serve to

reduce the impacts on native fauna along with the domesticated animals analysed in

Table 4-7.

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Table 4-7 Noise impact on animals

Management for blasting vibration and noise are as below:

• In the blasting work, it is judged that there will be no impact on noise and

vibration because the villages and houses are located far away.

• The Powerhouse and Access Road Lot 3-1 areas in the closest section are

monitored to ensure compliance with regulatory standards using a

measurement instrument

• In the case of blasting vibration and noise, there are many differences in the

conditions of terrain, features, climate, etc., so it is planned to select a blasting

method suitable for the blasting regulation standard through test blasting

before blasting.

4.6 NOISE AND VIBRATION MEASUREMENT INSTRUMENT

Noise and vibration will be monitored in accordance with the Air Quality and Noise

Monitoring Plan (AQNMP; M7). To illustrate the type of monitoring to be undertaken,

the specifications of the measurement instrument which will be used are shown in

Table 5.9

Source) Seoul National University College of Veterinary Medicine, A Study on the Evaluation Method

of Animal Damage by Noise, 2001.

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Table 4-8 Noise and vibration measuring device specifications

Calibration interval of instrument are as below:

• Interval of sound instrument and vibration instrument: 12 months

• Interval of calibration can be shortened or extended according to Instrument

precision, maintenance of accuracy, stability, purpose of use, environmental

conditions, frequency of use.

Management of instrument history are as below:

• Maintenance by instrument history card

• Maintenance by attaching a label on calibration tests.

4.7 BLASTING AND DRILLING PERMIT PROCESS

The blasting permit procedure is shown in the flow chart below and details are shown

in Table 4-9.

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Table 4-9 Blasting permit requirements

No Item Authorized organizations Required Documents Remark

1 User's License MID

(Ministry of Infrastructure Development)

1. Formal Letter 2. Qualification Blaster 3. Area of Blasting (map) 4. Amount of explosives to be used. 5. Payment receipt from the ministry of finance

Complete

2 Dealer's License

RSIPF (Royal Solomon Island

Police Force)

1. Formal request Letter 2. Copy of Users' License 3. Company registration certificate 4. Blaster's License/qualification 5. Payment receipt from the ministry of finance 6. Other relevant documents

Still preparing documents

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5 REPORTING AND AUDITING

5.1 REPORTING

Internally, the reporting hierarchy proceeds as follows: Subcontractor reports to the

HEC Construction Manager, who reports to HEC Project Manager (along with HSE

Manager). Externally, HEC reports directly to THL and the OE, and THL in turn reports

to the PO, Lenders and relevant authorities.

The subcontractor is responsible for reporting to the HEC Construction Manager and

requesting approval of the drilling and blasting activities. Moreover, the subcontractor

will report their HSE performance following the procedures and templates detailed in

the CESMP (P1) and WHSP (P8).

Monitoring of the efficacy of the mitigation measures will be conducted according to

the Air Quality Management and Dust Control Plan (AQMDCP), the Air Quality and

Noise Monitoring Plan (AQNMP; M7), and the Noise and Vibration Management Plan

(C13).

To ensure compliance with the requirements of this Drill and Blast Management Plan,

HEC’s environmental and social team will oversee monitoring and reporting. The

Team’s Supervisor will be responsible for compiling reports from monitoring for the

HSE Manager.

The scope of the reporting program to be undertaken by HEC is shown in Table 5-1.

Table 5-1 Reporting program

Preparation Review Content Frequency

Internal

Subcontractor Construction Manager

• Preparation and Completion of DBMP checklist to monitor correct implementation of mitigation strategies

• HSE Performance Report

• Prepare Method Statement and Risk Assessment according to HEC Risk Assessment Procedure (HEC-AH-H04-H03), the CESMP (P1) and WHSP (P8)

• Completion of material logs as per HMMP (P13)

Weekly, and every drill and blasting activity

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Preparation Review Content Frequency

HEC Environmental and Social Team

HEC Construction Manager and HSE Manager

• Visual inspection report for DBMP

• Revision of DBMP Checklist

Weekly

HEC Construction Manager

HEC Project Manager

• Results of visual inspection of DBMP control measures

Weekly

External

HEC Construction Manager and HSE Manager

THL • Results of visual inspection of DBMP control measures

• HSE Performance Report (monthly collection)

Monthly

5.2 AUDITING

HEC will be subject to internal and external audits. The internal audit will be conducted

by HEC Headquarters to the onsite team according to the HSE Audit Procedure (HEC-

AH-H04-H13). The internal examinations performed by the onsite staff are referred to

as inspections. External audits will be conducted by the E&S Manager from THL, E&S

Safeguards Manager from the PO, and the Owner’s Engineer (OE).The detailed

structure and content of auditing process is presented in the Construction

Environmental and Social Management Plan (CESMP; P1).The below Table 5-2

presents a summary of the process.

Table 5-2 Summary of auditing process

Auditor Auditee Frequency

THL E&S Manager HEC Every three months

HEC Headquarter HSE Team HEC onsite team Every six months

HEC HSE Manager and

Construction Manager

Subcontractor Every three months

PO E&S Monitoring team (with

Lenders Technical Advisor, LTA)

HEC Every three months

OE - Stantec HEC Every six months

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External and internal auditors will notify relevant Project Site staff about upcoming

audit events, via written notice. This will provide a mechanism to communicate the

schedule, activities and objectives of the audits. If urgent, the Project Site may be

notified via phone or fax.

The audit process involve reviewing onsite activities to assess compliance with the

management plans and / or HEC internal standards. The auditor will review all records

of previous audits and evaluate historic compliance and the use of appropriate

corrective actions.

Findings from the audit will be summarised in an audit report. A copy of the resulting

audit report is to be made available upon request for reference and, where necessary,

implementation of any identified corrective actions.

The key performance indicators to be considered when auditing this management plan

are:

• Number of incompliances recorded;

• Number of incompliances resolved;

• Number of incidents recorded related to drilling and blasting activities;

• Hazardous material transport logs up to date and available at the project

office;

• Quantity of explosives used weekly;

• Quantity of explosives transported to the storage bunker weekly; and,

• Number of training sessions completed.

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ANNEX A- DRILLING ACTIVITY DURING GEOTECHNICAL INVESTIGATION AND WELL

DEVELOPMENT

1. Drilling activity description of the geotechnical investigation

a. Plan and date of geotechnical drilling

Detailed investigation: 25 boreholes in 2019

Access road: no plan

b. Working photo of geotechnical borehole drilling

c. Drilling equipment dimension

Drilling Rig Name ES-0073 GY 150

Drilling diameter 76mm 76mm

Max drilling depth 250m 180m

Rig weight 5440kg 500kg

d. Environmental impact possibility

1) The core sampling procedures of the drilling rigs

This drilling rigs supply water between soil/rock and drilling case

faces, rotating the drilling rod and bit to sample a soil and rock

core.

Sampled soils are contained in small plastic vessels and all rock

cores are also extracted from the drilled borehole.

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Drilled boreholes had been sealed by cement grouting during

detailed investigation in May ~ August 2019. All samples were

transferred and well stored in warehouse.

2) Evaluation of environmental impact during the drilling

These rigs don’t produce any noise and vibration during the

borehole drilling because it rotates drilling rod to extract whole

rock core and soil samples, no percussion activity.

Since quantities of extracted soil are very limited and small, it’s

not necessary to dispose the spoiled parts.

The quantities of produced muddy water in soil layers are very

small and can be easily penetrated in ground. So, sedimentary

basin is not needed to install in the vicinity of drilling holes.

2. Drilling activity description of well development

a. Plan and date of well development in site

Planed well numbers: 4 wells

Planed depth: 100~200m subject to the aimed quantities

Drilling date: June, 2020

Planned location: Field office, power house, camp

b. Working photo of well drilling rigs and appurtenant equipment

Drilling rig Carrier Air compressor

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c. Drilling equipment dimension

Drilling Rig Name D & B 30W Remarks

Drilling diameter 200mm Outter casing

150mm Inner casing

Max drilling depth 300m

Rig weight 13,000kg

d. Environmental impact possibility

1) The procedures of the drilling rigs

This drilling rigs supply water and high pressurized air into the

drilling hole, percussing the rocks.

After drilling well boreholes, put the plastic pipe in whole depths

and grouting between pipe and drilled holes except the end parts

of pipe gathering ground water.

2) Evaluation of environmental impact during the drilling

These rigs produce noise and vibration during the borehole

drilling but the level of drilling sound decibel and vibration is low

and would be conducted in a day time only.

Also, HEC will notify to the nearby communities prior to the

commencement of these activities.

The produced slime quantities during drilling of well are limited

and also small. So, it’s not necessary to dispose this slime but HEC

will collect this slime and transport to the disposal.

The quantities of produced muddy water in soil layers are small

and can be easily penetrated in ground. So, sediment basin is not

needed to install in the vicinity of drilling holes.

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ANNEX B- DRILLING AND BLASTING PLAN

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ANNEX C – WELL DRILLING PLAN

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ANNEX D- DRILLING METHOD STATEMENT