State of the Tsolum River

Section 4

Section 6

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TABLE OF CONTENTS
Acknowledge ments
Report Contributors
SECTION 1. SUMMARY
SECTION 2.
PROJECT AND WATERSHED DESCRIPTION
SECTION 3.
VOLUNTEERS AND COMMUNITY INVOLVEMENT
SECTION 4. MEDIA AND PUBLIC EVENTS
SECTION 5. ACID MINE DRAINAGE
SECTION 6. WATER MONITORING
SECTION 7. FISH HABITAT MAPPING PROGRAMS
SECTION 8. REFUGE POND STUDIES
SECTION 9. RESTORATION PROJECTS
SECTION 10. FLOWS AND STORAGE REPORT
SECTION 11. ENHANCEMENT

CONTACT US

SECTION 5
Acid Mine Drainage

Introduction

In the late 1950’s, pink and coho salmon escapements in the Tsolum River started to decline. Despite enhancement efforts initiated by DFO at Headquarters Creek (a tributary of the Tsolum River) in 1968, fewer salmon returned to the river each year. By 1985, coho salmon runs numbering 7500 in 1957, were reduced to 800 while only 1000 pink salmon returned from runs that historically numbered over 75,000 (Deniseger et al 1995). Enhancement techniques that were successful in many other river systems were not working in the Tsolum River.

Federal and provincial investigations into the cause of the run declines began. Water samples revealed that copper concentrations in the mainstem of the Tsolum River were very high during the spring and fall. Researchers focused on the abandoned open-pit copper mine that operated on Mt. Washington from 1964 to 1967. Kangasniemi and Erickson (1986) stated that the failure of the Headquarters Creek salmon enhancement efforts resulted from unacceptably high dissolved copper concentrations in the Tsolum River. The high copper concentrations came from dissolved copper leaching from the old mine site, located on the east slope of Mt. Washington (Appendix A).

The now defunct Mt. Washington Copper Co. Ltd. and Cumberland Mining Co. Ltd. jointly operated two main pits at an elevation of approximately 1300 metres (Sierra Legal Defence Fund, 1998). Drainage from the south pit flows into the McKay Creek watershed. The north pit drains into the Pyrrhotite Creek watershed. The mined ore, chalcopyrite, was trucked 5 km south and 400 m lower to a crushing and concentrating mill on Murex Creek. The mill tailings were transferred via pipeline to a pond draining primarily into Wolf Lake. Of these four potential acid generating sites, to date only the north pit has been identified as a serious problem, while the other three sites are minor contributors of copper.

The term ‘acid generating’ refers to the production of sulphuric acid, which lowers the pH of surface and ground water. Copper and iron are found as sulphides in chalcopyrite. When this ore is exposed to oxygen rich water, the sulphide oxidises to sulphate, the iron oxidises to iron oxide and/or hydroxide, and sulphuric acid is released. Copper and other metals (aluminium, arsenic, iron, and zinc) dissolve in water at the reduced pH and leach into the Tsolum River headwaters. Drainage of this type from mine sites is called ‘acid mine drainage’ or AMD. This process, when naturally occurring or from non-mine disturbances, is known as ‘acid rock drainage’ or ARD.

The Effect of Copper on Salmon

There is little doubt that copper concentrations found in the Tsolum River cause damage to salmon. Salmonid studies reported by Deniseger et al (1995) indicate soluble copper concentrations in the Tsolum River must be reduced to below 7 micrograms/L to allow recovery of the salmon fishery. To achieve this result, approximately 95% of the mine discharge would require elimination or treatment when dilution by clean water in the lower watershed is lowest flow levels. Peak toxicity occurs during the spring freshet, when there is rapidly melting snow and little rainfall at lower elevations to dilute the copper dissolved in the runoff water. A secondary peak of toxicity exists during autumn, as coho salmon are entering the river. Dissolved copper levels are thought to cause adult salmon to avoid spawning in the Tsolum River mainstem. Salmon smolts migrating to the estuary are weakened or killed as high copper levels interfere with their ability to adapt to salt water. The effects of copper contained in sediments upon spawning salmon or incubating eggs are not well known. Despite evidence of mechanical transport of copper to 18 km from the minesite, the sediment-bound copper in the lower watershed appears to be highly stable such that the copper-rich sediments are unlikely to become a secondary source of dissolved copper (Deniseger and Kwong, 1996)

Evidence indicates that copper damages salmon by interfering with liver function, allowing other more toxic materials such as cadmium to cause further damage. In-stream bioassay studies have shown that salmon held in the Tsolum River die when dissolved copper concentrations are elevated by snowmelt or heavy rain at the minesite (Deniseger et al 1995). These results can be duplicated in the laboratory, where an LD-50 indicating the concentration of copper lethal to 50% of a sample of salmon is calculated.

Remediation Work from 1987 to 1992

A 1987 report by Steffen Robertson and Kirsten (BC) Inc. (SRK) documented a number of measures to eliminate or reduce copper concentrations in the Tsolum River. This report recommended consolidation of the acid producing mine waste rock, into a single pile on the northeast side of the north pit. They further recommended covering the pile with 1 to 1.5 metres of high silt glacial till. An additional impermeable membrane could be sandwiched within the till cover. As well, SRK recommended site monitoring for three years, to assess the effectiveness of the till cover. The report suggested covering the pit and perhaps the waste dump, if the pit also proved to be acid generating.

During 1988 and 1989, the north pit waste rock was consolidated and covered with one metre of the glacial till. It later became apparent that the north pit waste rock was not the only source of AMD. Evidently, there is porosity in the bedrock and/or fractures in the bedrock. A combination of these geological features and movement of localized water table levels has contributed to the acid leaching in the north pit proper.

Various measures were implemented during 1989 to 1992 (Galbraith, 1993). These measures included diversion of ground and surface water, covering suspected ‘hot’ spots with concrete and asphalt impregnated textiles, and in situ neutralization with lime (CaCO3 and Ca(OH)2). Most of these procedures involved movement of potentially acid generating material around the site.

Site monitoring also continued. Unfortunately, as a result of the additional measures, the effectiveness of the till cover is unclear. The provincial government spent approximately $1.5 million dollars in attempts to control AMD by capping the mine waste and ditching the surface water at the mine site. Despite these efforts, high copper concentrations continue to limit fish production in the Tsolum River (Brandt 1997).

Remediation Options

Source control and water treatments are two basic options for reducing copper concentrations to acceptable levels.

Source control

Source control involves halting the acid generating reaction, or preventing reaction products from entering fish bearing streams. Oxidative leaching can be slowed or stopped by preventing oxygen from contacting the copper ore. One method employs underwater submersion of the ore, tailings or waste. Oxygen, having a maximum solubility in water of 15 mg/L, is removed by biological action in deep water. Opportunities for convective re-oxygenation are limited. This method, successful so far at the Island Copper Mine near Port Hardy, is not suitable for the Mt. Washington site because of the elevation and the topography of the minesite.

Another source control method inhibits the entry of water to the mineralized zones thereby limiting the extent of leaching and the mobility of leached products. This is the rationale behind covering mine sites. This plan begins with diverting water entering the north pit by improving the diversion ditch that is located uphill from the pit. A Multi-layer cover could then be placed over the entire north pit (including the pit floor and the waste rock material). The design suggested by Haug 1997 includes a water impermeable layer of fine-grained material such as bentonite or fly ash (by product of pulp and paper manufacturing). The purpose of this layer is to exclude water and oxygen from coming in contact with the AMD. A second layer of soil will be placed on top of the impermeable layer and vegetation will be planted on top of the soil to protect the soil from erosion.

Water treatment

Treatment of contaminated water involves removal of the copper cation. Anions, such as sulphide, carbonate or hydroxide, will combine with the cation to form insoluble salts. These insoluble salts can be removed from water by precipitation or filtration methods.
Wetlands have the ability to naturally filter metals from water and neutralize AMD. Copper is initially removed from the water by the wetland vegetation. The vegetation dies, sinks to the bottom of the wetland and decays. The decomposition process removes oxygen, whereby sulphate is reduced to sulphide, which immobilizes the copper (Golder 1997). This natural phenomenon is limited to large wetlands experiencing low flows, relatively mild temperatures and acidity. It is not known if there is sufficient wetland area in the upper Tsolum River watershed to handle the very high peak copper loads which occur in the spring and fall.

Industrial treatment facilities employ neutralization materials, which can be rigorously controlled. These treatment facilities are readily available, but can be expensive. Long term operational funding would be required and the sludge produced as a byproduct of this process may endanger aquatic plants and animals downstream of the minesite. The heavy snow pack (over 10 meters in 1999) and lack of hydro power at the site may make it necessary for any treatment plant to be constructed at a lower elevation with the acid drainage being carried by pipeline down to the treatment plant (Golder 1997b).

Combination treatment options

Combined treatment systems involves in situ neutralization and wetland enhancement, with or without neutralization.

Control of upstream surface water flow should be added to source control and treatment options. Under certain conditions (e.g. low flow rates downstream), it may be advantageous to capture and store contaminated water for release when flow rates increase downstream. Smaller treatment plants may also be feasible if peak flows were stored and released more slowly, in effect, buffering the flow rates.

Generally, source control solutions are felt to be ‘permanent’. They will, however, require time to be effective and will probably be expensive, $4 to $10 million. Treatment solutions, meanwhile, require the ongoing expenses of materials, energy, sludge disposal. An evaluation of options and costs is being considered by the Acid Mine Drainage Work Group in the preparation of the AMD Action Plan.

TRTF Action Plan

Work on the mine problem since 1992 has, for the most part, been limited to monitoring strategic sites in the watershed and evaluating the options. Two local delegations lobbied provincial cabinet ministers for action on the mine. The first delegation met in 1995 with then Mines Minister, the Honourable Anne Edwards. In 1997, a second meeting was held with Mines Minister, the Honourable Dan Miller and Environment Minister, the Honourable Cathy McGregor. The Ministers suggested that funds would be forthcoming only after an action plan could assure the government that further work would be successful in lowering copper levels in the river.

Since March 1997, the Tsolum River Task Force’s AMD work group has been seeking to provide solid answers for the Ministers. The work group began by examining two treatment options. One option involves the feasibility of piping the concentrated mine run off to a site more accessible year round (Golder Associates, 1997b). The other involves the feasibility of passive/active wetland options (Golder Associates, 1997a).

The draft Action Plan produced by the work group outlines their present position with regard to minesite remediation (see Appendix B). The Action Plan will form the basis of the TRTF remediation proposal. This draft plan is a work in progress, intended to provoke discussion within the work group. It is subject to revision and the author of the site welcomes ideas that would improve the plan (Ferguson 1998).
This draft document can be viewed on the Internet website at
http://www.netcolony.com/members/wildwolf/actionplan/APtoc.htm.
A list of references relating to AMD from the Mount Washington mine can be found in Appendix C.

REFERENCES

Brandt, Charles 1997. Reclaiming a River published in the Comox Valley Echo;Friday September 26, 1997

Deniseger, J.H. McKean, C.J.P. and Chapman A.R. 1995. Tsolum River Watershed Water Quality Assessment and Objectives; Technical Appendix. B.C. Ministry of Environment, Lands and Parks, Victoria, B.C.

Deniseger J. and Y.T. Kwong, 1996. Rish assessment of Copper-Contaminated Sediments in the Tsolum River near Courtenay, British Columbia. Water Qual. Res. J. Canada 31(4): 725-740.

Galbraith, D.M. 1993. Mt. Washington mine reclamation project report on 1992 program—1992 post construction report. Prepared for Mt. Washington Reclamation Project, Ministry of Energy, Mines and Petroleum Resources.

Golder and Associated Ltd. 1997a. Passive and/or wetland treatment options for acidic mine drainage at the Mount Washington mine site, Courtenay, B.C. Final Report prepared for the Environmental Protection Branch, Environment Canada.

Golder and Associated Ltd. 1997b. Pipeline routing and conceptual design study for the diversion of Mt. Washington acid rock drainage. Report prepared for the Environmental Protection Branch, Environment Canada.
Deniseger, J.H. McKean, C.J.P. and Chapman A.R. 1995. Tsolum River Watershed Water Quality Assessment and Objectives: Technical Appendix. B.C. Ministry of Environment, Lands and Parks, Victoria, B.C.

Ferguson, Dave 1998. Mount Washington Action Plan, Tsolum River Task Force

http://www.crosswinds.net/actionplan/

Haug, M. and O’Kane M. 1998. Preliminary Assessment of Conditions at the Mt. Washington Mine Site. A draft report prepared for Canadian Pacific Railway, Calgary Alberta

Kangasniemi, B.J.and Erikson, L.J. 1986. A preliminary assessment of acid mine drainage from an abandoned copper mine on Mount Washington, B.C. Ministry of Environment, Lands and Parks.

Sierra Legal Defence Fund. 1998. Mt. Washington: The Money Pit. In: Digging Up Trouble—The Legacy of Mining in British Columbia. Sierra Legal Defence Fund, May 1998.

Steffen, Robertson and Kirsten (B.C.) Inc. 1987. Acid mine drainage abatement study, Mount Washington, Vancouver Island, B.C. Report 62701/1 prepared for the B.C. Ministry of Environment and Parks.

SECTION 5. APPENDIX A
Map of Mine Site

SECTION 5. APPENDIX B
Outline of Draft Action Plan
For remediation of Acid Mine Drainage at the Mt. Washington Minesite

Action	When	Approximate Max. Cost
1. Finish Action Plan	February 1999
2. Divert Uphill Water	Summer 1999	$0.5M - $1M
3. Seal off Pit Floor	Summer 1999 If necessary	$0M - $2M
4. Cover North Pit and Replant	Fall 1999	$2M - $3M
5. Enhance Wetlands	2003	$0M - $1M
6. Treatment Plant	2003 Only if necessary	$0 - $2M
7. Restore Salmon Habitat	1997 onward	$0.5 - $2M
8. Monitor on-going		$1M
TOTAL COSTS		$4M - $12M

SECTION 5. APPENDIX C
Bibliography from
AMD Draft Action Plan website.

Appendix C - Bibliography from AMD draft Action Plan website.
Bibliography -- Mount Washington Mine Action Plan
Coombs, David; Unpublished; "The Role of Narrow-Leaved cotton Grass (Eriophorum angustifilium, Honck.) in the Removal of Copper in a Sedge Fen receiving Acid Mine Drainage--Undated draft"; 239 pps.
Deniseger, John and L.W. Pommen; of MELP; "Tsolum River Watershed--Water Quality Assessment and Objectives"; Apr 21, 95; 96 pps for MELP.
Gadsby, John W.; Unpublished Proposal; "Developing a Copper Contamination Control Strategy for the Mount Washington Mine--"; Apr 01, 98; 25 pps for TRTF.
Galbraith, D.M.; of MEMPR; "Mt. Washington Mine Reclamation Project Report on 1992 Program--1992 Post Construction Report"; Mar 01, 93; 43 pps for Mt. Washington Reclamation Project.
Galbraith, D.M.; of MEMPR; "Mt. Washington Acid Mine Drainage Control Project -- Project Overview Report"; Dec 14, 95.
Galbraith, D.M.; of MEMPR; "Results of September 7, 1995 Field Trip to Mt. Washington -- ; Oct 17, 95; 1 pps for Mt. Washington Project Committee.
Kangasniemi, B.J. and Lloyd J. Erickson; of MELP; "A Preliminary Assessment of Acid Mine Drainage from an Abandoned Copper Mine on Mount Washington, B.C.--"; Apr 01, 86; 33 pps for MoE.
Mierzejewski, J. and T. P. Fitzell; of Golder Associates; "Pipeline Routing and Conceptual Design for Diversion of Mt. Washington Acid Rock Drainage--"; Apr 16, 97; 35 pps for EC-EPB.
Nix, Peter; of Golder Associates; "Passive and/or Wetland Treatment Options for Acidic Mine Drainage at the Mount Washington Mine Site, Courtenay, B. C. --"; Apr 03, 97; 62 pps for EC-EPB.
Olauson, Rodney C.; of SRK (Unpublished Proposal); "development of a Copper Contamination Control Strategy for the Mount Washington Mine--"; Apr 01, 98; 18 pps for TRTF.
Robertson, A., M. Eivemark, A. Brown, A.S.C., and J. Malick; of SRK; "Acid Mine Drainage Abatement Study, Mount Washington, Vancouver Island, B.C.--"; Jul 01, 87; 120 pps for MELP.
Wendling, Gilles and Sue Baldwin; of Levelton; "Mount Washington Copper Mine Data Review and Recommendations on Mitigative Measures--"; Jul 02, 98; 31 pps for TRTF.
Wiens, John H. and Peter C. Lighthall; of AGRA; "Opportunities Relating to the Remediation of acid Mine Drainage at Mt. Washington and the Restoration of the Tsolum River Watershed--"; Jun 06, 96; 27 pps for MELP.

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