teck coal ltd. - british...

November 2014 M09963A01.730

Teck Coal Ltd.

Fording River Operations

Dam Safety Inspection Report

Independent Third Party Review

141128R‐TCL‐FRO 2014 3rd PartyReview.docx M09963A01.730

Klohn Crippen Berger Ltd. • 500 - 2955 Virtual Way • Vancouver BC V5M 4X6 • CANADA 604.669.3800 t • 604.669.3835 f www.klohn.com

November 28, 2014

Teck Coal Limited Fording River Operations P.O. Box 100 Elkford, British Columbia V0B 1H0 Mr. Jason Garwood Senior Geotechnical Specialist Dear Mr. Garwood: Fording River Operations ‐ Dam Safety Inspection Report Independent Third Party Review Please find attached the Third Party Review of the Dam Safety Inspection (DSI) Report of the North Tailings Pond (NTP) and South Tailings Pond (STP) dams at your Fording River Operations. The review concludes that the DSI Report meets the requirements of the Ministry of Energy and Mines and that the dam classifications are appropriate. This report documents the basis for our review and identifies areas for ongoing improvement. Yours truly,

KLOHN CRIPPEN BERGER LTD. Harvey McLeod, P.Eng., P.Geo. Principal

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141128‐cover.docx

M09963A01.730 November 2014

Teck Coal Ltd.

Fording River Operations

Dam Safety Inspection Report

Independent Third Party Review

Teck Coal Ltd. Fording River Operations

Dam Safety Inspection Report Independent Third Party Review

TABLE OF CONTENTS

141128R‐TCL‐FRO 2014 3rd PartyReview.docx Page i

M09963A01.730 November 2014

1 INTRODUCTION ............................................................................................................................. 1

2 BACKGROUND INFORMATION AND SITE VISIT ............................................................................. 2 2.1 Site Visit and Document Review .................................................................................... 2

2.2 Facility Description ........................................................................................................ 2

2.3 Site Conditions ............................................................................................................... 4

3 REVIEW OF 2014 DAM SAFETY INSPECTION REPORT ................................................................... 5 3.1 General .......................................................................................................................... 5

3.2 Consequence Classification Review ............................................................................... 6

3.3 Instrumentation Review ................................................................................................ 6

3.4 Stability Review .............................................................................................................. 7

4 REVIEW OF TAILINGS FACILITY STEWARDSHIP ............................................................................. 8

5 SUMMARY ..................................................................................................................................... 9

6 CLOSING ...................................................................................................................................... 11

List of Tables

Table 3.1 Summary of DSI Conformance .......................................................................................... 5 Table 3.2 Dam Classification – “High” (CDA, 2013) .......................................................................... 6 Table 5.1 Summary of 2014 DSI Recommendations (Golder, 2014) ................................................ 9

List of Figures

Figure 2.1 Site Plan ............................................................................................................................ 3



141128R‐TCL‐FRO 2014 3rd PartyReview.docx Page 1

M09963A01.730 November 2014

1 INTRODUCTION

This report presents the results of an independent Third Party Review of the Dam Safety Inspection (DSI) Report for the Fording River Operations (FRO) North Tailings Pond (NTP) and South Tailings Pond (STP) dams. The DSI was performed by Golder Associates Ltd. (Golder). The Klohn Crippen Berger (KCB) review included a site visit by the Review Engineer, Mr. Harvey McLeod, P.Eng., P.Geo. on October 15, 2014.

KCB has recently (KCB, November 2014) completed a Dam Safety Review (DSR), which was carried out under the Guidance of the Association of Professional Engineers and Geoscientists of BC (APEGBC) and the Canadian Dam Association (CDA).

The Fording Coal Mine is located in southeastern British Columbia, approximately 25 km north of the town of Elkford. The mine produces approximately 9 Mt per year of clean coal. Fine coal refuse from the wash plant has been stored in two main facilities, North Tailings Pond (NTP) and South Tailings Pond (STP).

The tailings impoundments are regulated under the Mines Act of British Columbia and must comply with the requirements of the Health, Safety and Reclamation Code for Mines (HSRC) in BC (BC MEMPR 2008). The requirements related to tailings impoundments in the code include the following:

Dams must be designed in accordance with the criteria provided in the Canadian Dam Association, Dam Safety Guidelines (HSRC 10.1.5).

The Operation, Maintenance and Surveillance (OMS) manual must be revised regularly during operations (HSRC 10.5.2).

Annual Dam Safety Inspection Report (HSRC 10.5.3) must be carried out and submitted to the Ministry of Mines. The MEM website provides the document “Guidelines for Annual Dam Safety Inspection Reports”.

There must be an Emergency Preparedness Plan for any dam with a consequence classification of “High” or “Very High.” (HSRC10.6.8).

The current dam classifications for the NTP and STP dams, under the CDA Guidelines, are “High”. The MEM classifications under the HSRC are major impoundments and major dams.

KCB have been informed that the Engineer of Record (EoR) for the STP and NTP dams is Golder. The EoR is responsible for the design and performance of the dam including: 1) dam safety inspections; 2) construction monitoring and QA/QC; 3) instrumentation planning, design and review; and 4) design modifications.

On August 18, 2014, the Chief Inspector’s office of the MEM issued orders mandating that the 2014 Dam Safety Inspection (DSI) of tailing dams be completed, and that the report be reviewed by a third party Professional Engineer, and submitted December 1, 2014. The order required that the third party review:

assess if the DSI report meets the requirements of MEM; and

the consequence classification of the dam(s).




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2 BACKGROUND INFORMATION AND SITE VISIT

2.1 Site Visit and Document Review

A dam site inspection and a comprehensive review of available data, which included over 50 documents, was carried out for the Dam Safety Review (KCB 2014) and used as background for the review of the DSI report. A summary of these documents is included in the Reference Section of this report.

A site visit was also made on October 16, 2014 and included Mr. Harvey McLeod (KCB), Mr. Jason Garwood (FRO Engineering) and Andrew Bidwell (Teck Coal). The tour included inspection of the NTP and STP. A walking tour of the downstream toe of the STP was carried out to view the areas of seepage that had been noted.

Some of the key observations made during the site visit included:

As reported in the DSI, seepage was observed along the toe of the West Embankment of the STP which appeared to be occurring near the soil contact between either the dam fill or localized flood plain deposits and the lower permeability glacial till. Seepage was clear and there was no indication of piping and the seepage is not a stability concern.

No seepage was observed at the NTP.

The dams were in good repair and there was no evidence of any significant erosion, slumping, cracks, or bulges.

2.2 Facility Description

The NTP and STP serve as storage areas for tailings and attenuation of water from coal processing operations. The NTP is located on the west side of the Fording River across from the plant. The NTP is currently used to attenuate runoff water and as a settling pond for runoff from local rock dumps. The STP is located south of the plant on the east side of the river and has been used for tailings storage since 1982 and is the active tailings storage area. A location plan showing the facilities is presented on Figure 2.1.

The NTP dam is approximately 24 m high and approximately 1295 m long. The STP dam is approximately 32 m high and approximately 2079 m long. The dams are zoned earthfill dams constructed using locally borrowed glacial till fill for the starter dam and the upstream glacial till blanket. Subsequent downstream raises of the dam used glacial till for an upstream low permeability zone and Coarse Coal Refuse (CCR) for the downstream shell or, more recently, a mixture of CCR and fine coal refuse. The downstream slopes vary from 1.35H:1V to 2.7H:1V.




M09963A01.730 November 2014

Figure 2.1 Site Plan




M09963A01.730 November 2014

2.3 Site Conditions

The generalized surficial geology of the area consists of recent colluvium overlying the bedrock slopes and intermingled with the Fording River floodplain deposits, overlying glacial till and bedrock. The tailings ponds are constructed on these Fording River floodplain deposits. Generally, the sites are underlain by organic silt, overlying inter‐bedded floodplain sands and gravels, overlying glacial till, overlying siltstone and shale bedrock.

The area is moderately seismic and the 1 in 2475 return period earthquake is a magnitude M7 with a peak ground acceleration (PGA) of 0.12 g.

Average annual precipitation at the site is 661 mm which includes 324 mm of rain and 337 mm of snow (Golder 2014b). In June 2013, a flood of the Fording River occurred following heavy rains (approximately 140 mm over 36 hours). Incorporation of this event into the data set for return period estimate for the Sparwood Station (1157630) increased the 200 year 24 hour precipitation estimate from 61.5 mm to 96.4 mm (KWL 2013).

The Fording River parallels the NTP and the STP, and construction works were carried out in 2013 to upgrade the riprap protection for the dams. An update of the flood estimates, considering the occurrence of the 2013 flood was not available for review.




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3 REVIEW OF 2014 DAM SAFETY INSPECTION REPORT

3.1 General

The 2014 Dam Safety Inspection (DSI) was conducted by Golder and the report was provided to KCB on November 27, 2014. The DSI report is comprehensive and addresses the MEM guidelines for a DSI. The contents of the DSI have been compared against the MEM guidelines for preparation of a DSI Report and the results are summarized in Table 3.1.

Table 3.1 Summary of DSI Conformance

Requirement of DSI Included in DSI

KCB Observations

Executive Summary

Classification of the dam(s) in terms of Consequence of Failure in accordance with Table 2‐1 of the CDA Dam Safety Guidelines (2007).

Yes

Significant changes in instrumentation and/or visual monitoring records.

Yes

Significant changes to dam stability and/or surface water control.

Yes

For major impoundments, as defined in Part 10 of the Code, a current Operation, Maintenance and Surveillance (OMS) Manual is required. The annual report shall indicate the latest revision date of the OMS manual.

Yes Latest revision is September 2014.

For tailings dams classified as High, Very High or Extreme Consequence, an Emergency Preparedness Plan (EPP) is required. The annual report shall indicate the latest revision date of the EPP document.

Yes

Latest revision is January 2012 FRO are reviewing an updated OMS, dated September 20, 2014.

Scheduled date for the next formal Dam Safety Review (DSR) in accordance with Table 5‐1 of the CDA Dam Safety Guidelines (2007). Formal DSRSs are required every 5 to 10 years (depending on consequence classification) and differ from annual dam safety inspections. The DSR may be conducted by the Engineer of Record with third party review, or by an independent third party with involvement of the Engineer of Record.

Yes Last DSR completed November 2014. Next DSR should be completed by 2021.

Summary of past years’ construction (if any) with a description of any problems and stabilization.

Yes

Plan and representative cross sections. Yes

Site Photographs. Yes

Review of climate data. Yes

Water balance review. Yes

Freeboard and storage availability (in excess of the design flood). Yes

Water discharge system, volumes, and quality. NA Not applicable as there are no water discharges from the impoundments

Seepage occurrence and water quality. Yes

Surface water control and surface erosion. Yes

Instrumentation Review

Phreatic surfaces. Yes Piezometer readings given

Settlement. Yes

Lateral movement. Yes




M09963A01.730 November 2014

3.2 Consequence Classification Review

The DSI classifies both the NTP and the STP as “High” consequence structures based on the Canadian Dam Association Dam Safety Guidelines (2007, revised in 2013) and a summary of the corresponding consequence basis is shown in Table 3.2. Dam consequence classification should be selected based on the criteria shown in each category of incremental losses, and supported by relevant quantitative or qualitative evidence.

The DSI indicates that updated inundation studies of the NTP and STP are ongoing and are expected to be completed in December 2014. KCB reviewed a draft of the report, which indicated that the dam breach flood wave could extend past Fernie, British Columbia and potentially affect a number of residences.

Table 3.2 Dam Classification – “High” (CDA, 2013)

Structure Population at Risk

Incremental Losses for “High” Consequence Dam

Loss of Life Environmental and Cultural Values Infrastructure and Economics

NTP Dam Permanent 10 or fewer Significant loss of fish and wildlife habitat, but for which compensation in kind is

possible. Significant

STP Main Tailings Dam

Permanent 10 or fewer Significant loss of fish and wildlife habitat, but for which compensation in kind is


STP West Tailings Dam

Permanent 10 or fewer Significant loss of fish and wildlife habitat, but for which compensation in kind is


The DSI report indicates that the results of the inundation study, once complete, will be used to review the environmental consequence classification. KCB are in agreement with the dam classifications and the approach for reviewing the environmental consequence classification. For record purposes, FRO should explicitly quantify and document the supporting information that provides the basis for dam classification for each of the four consequence categories shown in Table 3.2.

3.3 Instrumentation Review

The instrumentation program is appropriately summarized and presented in the DSI. KCB observations on the piezometer instrumentation include the following:

There are 8 standpipe piezometers and 10 vibrating wire piezometers, with 2 piezometers each in 5 locations, in the STP Dam. Standpipe monitoring well data for the STP indicates that water levels in the downstream shell of the dam are near or below original ground surface, and rise to midway in the dam near the dam centerline.

There are no piezometers in the NTP Dam. However, the downstream shell is expected to be well drained, with a phreatic surface near ground level, based on observations of the high permeability of the material and the lack of observed seepage.




M09963A01.730 November 2014

Instrumentation at the STP includes 8 survey prisms (prior to the 2013 dam raise) which were recently replaced with 5 GPS monitors after the prisms were removed in advance of the 2013 dam raise. Instrumentation at the NTP dam includes 7 survey prisms on the dam crest, plus one reference prism (#10) that is not located on the dam that is used as a benchmark.

Movement plots from the annual geotechnical inspections were also prepared as part of the DSR (KCB, 2014). The data indicates minor settlement and deformation downstream, which is considered to be normal behaviour for the dam fill.

3.4 Stability Review

The DSI indicates that the dams are stable under the design conditions and KCB agrees based on the instrumentation data and the annual inspections. Localized erosion channels on the dam slopes were noted in the DSI and observed during site visits. This superficial erosion is not a significant concern to stability and can be mitigated through maintenance.

The seepage observed in the site visit was clear with no evidence of piping. KCB reviewed the filter compatibility of the Coarse Coal Refuse and Coarse Coal Fine Refuse for the DSR, and confirm that the gradations are filter compatible with the glacial till core and the foundation silty sands and gravels.

The tailings impoundments are operated on a “no‐discharge” basis with water recycled to the process plant and a minimum dam freeboard maintained for dam safety. Water is not discharged from the facility. The dam safety freeboard is being maintained for both the NTP and STP.

Seepage rates out of the STP are significantly influenced by the buried alluvial channel and by the rate of pumping from the seepage recovery wells located near the toe of the Main Dam. Overall seepage from the STP is on the order of 45 L/s to 150 L/s. The increasing rate of seepage is not causing the phreatic surface in the dam to rise and, therefore, is not a dam safety concern at this time.

Seepage from the NTP was not observed during the 2014 DSR site visits, however, it is likely reporting subsurface, which is consistent with the expected site conditions and supports the conclusion that the dam is well drained.




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4 REVIEW OF TAILINGS FACILITY STEWARDSHIP

FRO has a good team in place for managing and constructing the facilities and for providing oversight on the technical, environmental and social aspects. FRO manage and maintain the facility adequately and procedures are well documented. The OMS Manual is complete and procedures are in place to manage and respond to emergencies.

Notwithstanding the preceding assessment and conclusions, our review identified several suggestions for improvement, the identification of which does not mean that there is a lack of oversight in ensuring the ongoing safety of the tailings dam, but rather, is intended to assist FRO towards streamlining and strengthening their ongoing dam safety management system. These items include:

Prepare a separate organization chart that clearly defines the FRO “person responsible for the tailings facility”, e.g. “Tailings Engineer”, who is responsible for the tailing facilities. Identify who the person reports to and what other persons report to the person for matters pertaining to the tailing facilities.

Document the 4 components of the dam consequence classification, based on a review of the Inundation Study and supporting information.

Some improvements to the Operations, Maintenance and Surveillance (OMS) Manual and the Emergency Preparedness Plan (EPP) are suggested to address “gaps” in documentation.




M09963A01.730 November 2014

5 SUMMARY

The assessment of the physical conditions of the dams and associated works is thorough and comprehensive and no significant concerns have been identified. Management systems are in place, including an OMS Manual and an EPP. The DSI Report is compliant with the MEM Guidelines.

For reference purposes the key recommendations from the Executive Summary (Golder 2014) are reproduced in Table 5.1.

The dam classification of “High” is appropriate. Nonetheless, KCB agree with the DSR recommendation that the “environmental consequence” be further quantified after a review of the inundation study is completed.

Table 5.1 Summary of 2014 DSI Recommendations (Golder, 2014)

No. Recommendation Summary Timeline Priority1

NTP

2014‐01 Repair minor erosion on downstream slope near south abutment. Q3 2015 4

2014‐02 Prepare abandonment plan for buried pipes. Q2 2015 3

2014‐03 Implement actions to stabilize spoils at the north end and west side from Teck 2014 report North Tailings Pond – Reject Spoil Runout Analysis.

Q1 2015 2

2014‐04 Regrade crest as part of ongoing maintenance. Q3 2015 4

2014‐05 Re‐establish periodic surveys of Prism NT5. Q1 2015 3

2014‐06 Fill voids in downstream slope created by burrows. Q3 2015 4

2014‐07a Make equipment for emergency response to overtopping risk available on standby and test annually.

Q4 2015 3

2014‐07b Assess the best combination of active and passive emergency systems during various stages of the pond life cycle. Provide a construction schedule for the selected system.

Q2 2016 4

2014‐08a Complete hydraulic review of Fording River flood events and confirm riprap elevation and sizing along dam toe.

Q3 2015 2

2014‐08b Construct erosion protection to design flood level Q3 2016 2

STP

2014‐09 Repair erosion channels on downstream slope. Q3 2015 3

2014‐10 Protect surface of crest with layer or gravel. Q1 2015 4

2014‐11 Survey railway buttress to confirm completion of 2014raise of buttress. Q4 2014 4

2014‐12 Assess the best combination of active and passive emergency systems during various stages of the pond life cycle. Provide a construction schedule for the selected system.

Q2 2016 4

2014‐13 Install additional monitoring points as per previous Golder recommendations (Instrument Plan for South Tailings Pond Dam, 2014)

Q1 2015 3

2014‐14 Create outlets along safety berms for water Q1 2015 4

2014‐15 Regrade upstream slope to design (1.75H:1V) Q1 2015 2

2014‐16 Measure flows at culvert at north end of West Dam. Direct as much seepage as possible below West Dam to collection points for regular

Q3 2015 3




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No. Recommendation Summary Timeline Priority1

measurement.

2014‐17

Complete resloping and riprap placement south of STP Stn. 0+600. Further geotechnical assessment should be completed for the reconstruction of the STP toe around Stn 0+670 to tie the riprap into the bedrock or protect the bedrock.

Q3 2015 2

2014‐18a Complete hydraulic review of Fording River flood events and confirm required riprap elevation and sizing along dam toe.

Q3 2015 2

2014‐18b Construct erosion protection to design flood level Q3 2016 2

Note 1. Priorities defined in Golder 2014 as follows: Priority 1 – A high probability or actual dam safety issue considered immediately dangerous to life, health or the environment, or a significant risk of regulatory enforcement. Priority 2 – If not corrected could result in dam safety issues leading to injury, environmental impact or significant regulatory enforcement; or a repetitive deficiency that demonstrates a systematic breakdown of procedures. Priority 3 – Single occurrences of deficiencies or non‐conformances that alone would not be expected to result in Dam safety issues. Priority 4 – Best Management Practices – Further improvements are necessary to meet industry best practices or reduce potential risks.




M09963A01.730 November 2014

REFERENCES

British Columbia Ministry of Mines and Petroleum Resources. (BC MEMPR). 2008. Health Safety and Reclamation Code for Mines (HSRCM). 2008.

Canadian Dam Association (CDA). 2007. Technical Bulletin. “Dam Safety Guidelines (update 2013).

Golder Associates Ltd. (Golder). 2014. 2014 Annual Tailings Dam Safety Inspection. November 10, 2014.

Klohn Crippen Berger (KCB). 2014. Fording River Operation Dam Safety Review North and South Tailings Ponds. November 2014.

Note: The following tables formed part of the Dam Safety Review (KCB 2014).

South Tailings Dam ‐ Design Documents and Construction Records

Date Prepared

By Title

Inspection (I), Design (D) or Construction

(C)

Key Items of Interest

January 1976

Golder Associates

Tailings Storage Proposed 1977 Extension

D Design for STP, 11 boreholes near upstream toe of dam & 5 on diversion channel

May 1976 Golder

Associates

Second Report to Fording Coal Ltd. On Tailings Storage Proposed 1977 Extension

D

Results of 1976 subsurface investigation of deep gravel‐filled channel, including borehole logs and revised section drawing. Recommendations on design and construction of dyke and diversion channel.

August 1978

KWL “Thickened Tailings Disposal System”

D Study by Trow on seismicity of the area

1979 Golder

Associates Dyke Stability Report I

February 1981

Golder Associates

Assessment of Stability, Settling and Tailings Ponds Retention Dykes

I Observations on NTP and STP. High seepage at south end of STP. Seepage return wells were installed.

July 1982 Golder & KWL

Phase Two Expansion of South Tailings Pond

D Specifications provided for dam raise and water works

January 1984

Greg Trout Report on South Tailings Pond 12 Foot Lift

C Construction record. Inspections by Golder

August, 1984

Golder Associates

Raising the Level of South Tailings Dam

D Golder provided design basis for glacial till blanket for the upstream east abutment

January, 1997

Golder Associates

The Engineering Properties of Compacted Coarse Coal Rejects

D Density and strength data

October 2003

KWL Fording River – Floodplain Mapping and Analysis of Proposed Spoil Site

D

July 2006 Golder

Associates

2006 Dam Safety Review North and South Tailings Dams at Fording River Operations Elkford, B.C.

I Recommendation to prepare a downstream inundation map.

November 2007

KWL Fording River Flood and Erosion Analysis

D 500 year flood (144 m3/s) 1,000 year flood (180 m3/s)

February 2008

Golder Associates

Summary of in situ density and laboratory testing on combined

D Shear strength of CCFR ‐41° to 44°. Dry density: 1382 kg/m3 and 1665 kg/m3




M09963A01.730 November 2014

Date Prepared

By Title


(C)


coarse and fine rejects, Upper Blake reject spoil, Fording River Operations

March 2009

KWL Fording River Riprap D Design sections and costs for riprap

April 2009 Golder

Associates Draft Report: Design Review South Tailings Pond Dam

D Includes IDF basis, stability and seepage analyses

September 2010

Teck South Tailings Pond – Design and Construction Record

C 2 m lift, as built sections

March 2011

Golder Associates (2011a)

2010 Annual Geotechnical Assessment of Fording River Operations North and South Tailings Pond

I

Recommendations: Seepage zone at STP West Dam should be monitored weekly, standpipe piezometers should continue to be monitored

May 2011 Golder

Associates (2011b)

FRO South Tailings Pond Deposition Modelling

D

October 2011

Golder Associates (2011c)

Design Update South Tailings Pond D Included QA/QC Specifications

March 2012



I 0.3 m displacement observed at STP1 prism at north abutment

May 2012 Golder

Associates (2012b)

FRO South Tailings Pond Abutments Investigation

D

July 2012 Golder

Associates (2012c)

South Tailings Pond Dam Crest Raising Guidelines – Technical Memorandum

D

August 2012

Golder Associates (2012d)

South Tailings Pond Dam Raise Drawings, North and South Dam Abutment Plan, Profile, and Detail Drawings, Rev 0

D Issued for construction

September 2012

Golder Associates (2012e)

Technical Memorandum – STP Dam North and South Abutments

D

Review of foundation conditions of north and south abutments, design crest alignment review (north and south abutments), proposed glacial till key‐in excavation plan, north and south dam abutment design drawings issued for construction

February 2013

Teck 2012 Annual Water Balance – Washplant and South Tailings Pond

I Seepage from South Tailings Pond estimated at 2,045.4 x 103 m3/year

March 2013



I Recommendations: Repair minor erosion; reinstate all survey prisms.

April 2013 Golder

Associates (2013b)

South Tailings Ponds Dam 2012 – Construction Dam Raise As‐Built Report

C As‐ built construction record




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Date Prepared

By Title


(C)


June 2013 Ministry of Energy and

Mines Report of Geotechnical Inspector I

Site visit and associated Orders, following the 2013 flood event.

August 2013

Golder Associates (2013c)

2012 As‐Built Drawings, 2013 Design Drawings, Rev 0

D

2012 South Tailings Pond As‐Built plan, 2013 design plan, profile & sections, 2012 interim berm as built, and 2013 interim berm design drawings (issued for construction)

July2013 KWL Preliminary Estimates of June 2013 Flood Event

D Impact of flood of hydrology assumptions

February 2014


Instrumentation Plan for South Tailings Pond Dam

D Includes description of existing instrumentation

March 2014

Golder Associates (2014b)


I

South Tailings Pond design crest elevation of 1638.3 was reached with construction carried out in 2013. For north and south abutments, possibility of raise to El. 1639.6 m being investigated. Railway buttress should be raised to maintain freeboard.

May 2014 Golder

Associates (2014c)

Summary of Design Issues Affecting South Tailings Pond Additional Raise

D Notes the potential weaker foundation soils associated with the flood plain deposits. Notes limitations of raising the STP dam.

August 2014

Golder Associates (2014d)

2013 South Tailings Pond Dam Flood Repairs Construction Summary ‐ DRAFT

C Document only covers the STP dam and does not address QA/QC of riprap placement.

North Tailings Pond Dam ‐ Design Documents and Construction Records

Date Prepared

By Title


(C)

Comments

October 1969

Golder, Brawner &

Associates Ltd.

Report to Cominco Ltd. On Tailings Pond and Dyke Proposed Fording River Coal Project

D Recommendations provided for tailings pond development, and tailings dyke construction.

April 1970 Golder Brawner Associates

Second Report to Cominco Ltd., On Tailings Pond and Dyke Proposed Fording River Coal Project

D

Laboratory test results of fine and coarse tailings, and glacial till, recommendations for tailings pond development and tailings dyke construction.

May 1971 Golder Brawner Associates

Kootenay Engineering Ltd. Fording Coal Project Specifications for Construction of Phase 1 Tailings Dyke

D Specifications for construction of Phase 1 tailings dyke.

May 1973 Golder Brawner Associates

Report to Fording Coal Ltd. On Tailings Dam, Site Visit & Discussions

I

Record of In situ density tests of surface tailings material (no results), evaluation of present tailings dam conditions, discussion of design consideration

May 1974 Golder Brawner

Recommended Control Testing During Construction of Phase 3

D Specifications for foundation preparation, instruction for field density testing




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Date Prepared

By Title


(C)

Comments

Associates (1974a)

Zone 1b of fording Coal Tailings Dyke

procedure.

August 1974

Golder Brawner Associates (1974b)

Report to Fording Coal Limited on Phase 3 Tailings Dam Construction

C Construction record and review of field and laboratory test data provided.

February 1981

Golder Associates

Assessment of Stability, Settling and Tailings Ponds Retention Dykes

I Observations on NTP and STP. High seepage at south end of STP. Seepage return wells were installed.

July 2006 Golder

Associates

2006 Dam Safety Review North and South Tailings Dams at Fording River Operations Elkford, B.C.

I Recommendations to review the riprap size at the NTP toe and to prepare a downstream inundation map.

March 2011



I

Recommendations: Repair minor erosion on downstream slope of NTP, prepare abandonment plan for buried pipes that pass through NTP crest

March 2012



I

Recommendations: Confirm condition of reclaim pumps and pipes for emergency operation; survey water level monthly; re‐grade crest; review stability of waste materials on tailings beach.

September 2012

Golder Associates (2012f)

Fording River Operations Geotechnical Investigation of Existing Coal Tailings

D

Site investigation includes CPT, auger drilling, sampling, laboratory testing (index testing, slurry consolidations, shear strength), preliminary engineering analyses.

March 2013



I

Recommendations: Confirm condition of reclaim pumps and pipes for emergency operation; survey water level monthly; re‐grade crest; review stability of waste materials on tailings beach; place riprap at toe.

June 2013 Ministry of Energy and

Mines Report of Geotechnical Inspector I

March 2014

Golder Associates (2014b)


I Recommendations: Repair crack in fill at flood repair area; place soil cover on flood repair area.