37th Annual Mine Reclamation Awardsby TRCR on Nov 13, 2013 • 1:51 pm Leave a Comment
SUMMARY/REPORT OF THE AWARDS SUBCOMMITTEE
2013 Presentation of the 2012 Mine Reclamation Awards
Presented at the Reclamation Symposium Awards Banquet
September 18, 2013, Vancouver, British Columbia
View / Download: TRCR RELEASE Mine Reclamation Awards 2013-09-19;
TRCR 2012 awards presentation1
Thirty seven years ago, the British Columbia TRCR established a Reclamation Award to recognize outstanding achievement in mine reclamation in British Columbia. In addition to this major award, the committee may also recognize reclamation successes through category awards for metal mining, coal mining, sand and gravel, quarries, placer mining and mineral and coal exploration.
The awards may recognize work of major or minor extent, and may be the result of a group of people or a single person’s activities. These awards are assessed based on:
- quality in research
- innovation in techniques
- quality of work undertaken,
- extent of land reclaimed
- work of a high standard that has been conducted over a number of years.
This year the awards committee, comprising Kim Bellefontaine, Ministry of Energy and Mines, Craig Stewart with the BC Ministry of Environment, David Ewing with the Mining Association of BC and Wendy Gardner with Thompson Rivers University, chose to give two awards from the 7 nominations in 3 categories that were received. There continues to be evidence that strong reclamation efforts are being made throughout the province. It is clear that there is substantial planning and innovative thinking and techniques being tested at sites and this will pay dividends in the future both in terms of research that others can learn from and results that are exemplary for industry as a whole. The committee commended the efforts to date and looks forward to seeing future nominations from these and other sites that describe continued efforts and reclamation results.
ANNUAL BRITISH COLUMBIA JAKE MCDONALD RECLAMATION AWARD
The recipient of the 2012 British Columbia Jake McDonald Mine Reclamation Award was Teck Metals Ltd. for their outstanding reclamation achievements at the historic Pinchi Mine.
The Pinchi Mine is located on the north shore of Pinchi Lake, in north-central British Columbia, approximately 25 km northwest of the community of Fort St James. This historic mercury mine was originally owned and operated by the Consolidated Mining and Smelting Company, which later became Cominco Ltd., a predecessor of the current owner Teck Metals Ltd.
Between 1940 and 1944, cinnabar ore was mined from both surface glory hole and underground workings and ore was coarsely crushed and roasted to recover mercury. Much of the production was used to support the allied efforts of the Second World War. The roaster wastes (called calcines) were deposited on the shoreline and into Pinchi Lake, long before the environmental dangers of mercury were well known. Subsequent to that 1940’s phase of operations, all structures were demolished. From 1968 to 1978 the mine was developed for a second time with more modern processing involving crushing, froth flotation circuits, and roasting of concentrate. Coarse tailings were backfilled underground and fine tailings were deposited into an impermeable tailings impoundment. The mine then went into a long dormant phase of care and maintenance.
The early 1990’s marked the beginning of Teck’s painstaking work to develop a closure plan for the site. Due to the significant environmental and health and safety risks associated with mercury, the planning and decommissioning process for the Pinchi mine was lengthy, challenging, and unique in many ways. Numerous studies were conducted to understand the sources, pathway and fate dynamics of mercury in both the aquatic and terrestrial environments using ecological risk assessments and formalized risk analyses. Aquatic assessment involved regional fish mercury and lake ecology studies. The terrestrial ecological risk assessment involved literature review, extensive field investigations, habitat surveys, food chain modeling, and the development of toxicity reference values for methyl mercury and several other metals. Ecological risks at the site were evaluated for 40 different wildlife species.
As a result, it was determined that only those species that feed primarily on insects or small mammals indicated potential risks, mainly from arsenic, inorganic mercury, and methyl mercury uptake. It was determined that the remediation of the millsite and tailings areas would further reduce the risks to wildlife. Other areas, with elevated inorganic mercury in soils were deemed to pose negligible to moderate risk but were not targeted for further remediation, as the risks to wildlife were considered to be higher if the naturally recovering habitat was disturbed.
An integral part to the development and acceptance of the Closure Plan was a comprehensive consultation process with the Tl’azt’en First Nations, and the Nak’azdli Band which began in 2005 and is still ongoing today. A Technical Working Group was formed and the local First Nations played a vital role in reviewing studies, directing additional studies and ultimately in finalizing the remediation strategies for reclamation and closure of the site.
One of the most challenging aspects of the closure plan related to the mercury contaminated processing facilities. Typical of many sites of that era, the mill contained a range of hazardous chemicals, friable and non-friable asbestos materials, lead paints and PCBs that required special handling and disposal. In addition, the mill buildings and equipment had substantial mercury contamination, which required extensive cleaning and testing prior to dismantling and disposal to a new on-site landfill located in the West Zone Pit.
The presence of low permeability glacial till, combined with the ability to backfill a large portion of the pit and eliminate a large portion of a waste rock dump, made the West Zone Pit the most attractive disposal option. Building debris was hydrologically isolated by placing the materials away from the sidewalls of the pit on top of a 10 metre thick layer of waste rock. The landfill was then capped with a 1 metre till cover, and any seepage drains to the underground workings and discharges out of the reclaimed 750 level portal where it is regularly monitored.
Mercury vapour exposure during the demolition and closure activities posed significant worker health and safety risks. Thus Teck established very strict protective procedures for workers. As well, much of the work was conducted during the colder winter months, when mercury vaporization was reduced due to lower temperatures.
The shipping and disposal of 47,000 kg of mercury contaminated residues posed significant challenges. The disposal had to be done in a manner that was acceptable to Teck’s Product Stewardship Committee which requires recycling, life cycle assessment of products, and the minimization of impacts to people and the environment. The selected option involved shipping materials for recovery of mercury to the Clean Harbour facility in Quebec. Cleaned residuals were stabilized and landfilled at the Clean Harbour Lambton facility in Ontario while the liquid mercury recovered was shipped to Bethlehem Apparatus Co. in the US where it was roasted and sold as a marketable product.
Decommissioning of the 22 hectare tailings impoundment area included constructing an active spillway to reduce the phreatic surface and remove ponded water from the facility. This was done to enhance geotechnical stability and to eliminate the significant ecological risks associated with methylation of mercury and uptake through the food chain. The elimination of aquatic habitat in the tailings impoundment removed the exposure pathway for uptake. The subsequent terrestrial risks to browsing and burrowing animals from mercury in dry tailings was further reduced by spreading a layer of stabilizing iron sulphate sludge over the tailings and then capping with 1 metre of till. The capping of the tailings was also done in the winter to facilitate equipment working on top of the low strength tailings. The tailings were then revegetated using mixture of grasses, shrubs and trees.
The Pinchi Mine has now been successfully closed. To ensure that the remaining infrastructure and environmental conditions at the site remain stable over time and continues to meet regulatory requirements and closure plan objectives, Teck is implementing comprehensive geotechnical and environmental monitoring as well as formalized risk management plans
Pinchi Tailings impoundment (top) and Main zone pit area (bottom)
Bruce Donald and Michelle Unger accepted the 2012 British Columbia Jake McDonald Mine Reclamation Award on behalf of Teck Metals Limited.
L-R Dave Nikolejsin, Deputy Minister, Ministry of Energy and Mines, Ryan Mills, AECOM and Jaimie Dickson, 2013 Chair of TRCR
2012 METAL MINING RECLAMATION AWARD
The award for outstanding achievement for reclamation at a metal mine was presented to the Crown Contaminated Sites Program of the Ministry of Forests, Lands and Natural Resource Operations, as well as AECOM Canada Ltd. for their combined work at the historic Atlin Ruffner Mill and Tailings site.
The Atlin Ruffner Mill and Tailings site is an orphaned mine located on Crown Land near the town of Atlin in northwest British Columbia. The Ruffner mining area was first developed in 1899 and work continued intermittently until 1981. The deposit primarily produced silver, lead and zinc, along with some gold, copper, molybdenum and tin from underground workings. Small by today’s standards, approximately 3,500 tonnes of ore was milled at the Ruffner mine site.
The site was brought to the attention of the BC Crown Contaminated Sites Program by the local regional district and ranked as a priority site in 2008. Infrastructure at the site included a mill building with machinery, ore storage bins, two mill pads, two trailers, a shack, an explosives shed, a tailings pond, two sedimentation ponds and an actively discharging adit.
Testing throughout the site determined that concentrations of many metals including arsenic, lead, zinc, antimony, copper, silver and cadmium were found to exceed Contaminated Site Regulation standards and indicated high risk conditions. Samples were also found to exceed the Hazardous Waste Regulation Leachate Quality Standards for various metals. Because of the presence of leachable hazardous waste, the age of the mill and lack of activity since the 1980’s, the site was classified as a “historical hazardous waste contaminated site” under the Hazardous Waste Regulation.
The initial site investigations showed that water discharging from the adit, and the local groundwater at the site met standards, with the exception of cadmium and zinc. Concentrations of these parameters decreased substantially within 100 m down gradient from the site suggesting that metals were not being transported by leaching, and further indicating that this aspect of the site did not require specific remediation plans.
Thus the main objective of the remediation plan for the Atlin Ruffner site was to provide a robust, cost-effective, long-term solution to reduce long-term risk related to chemical contaminants. While most projects always aim to be as cost-effective as possible, this is particularly important for the Crown Contaminated Sites Program, as all of their activities are publically funded.
The focus of the remediation plan was to reduce the physical exposure of contaminated soils by placing a one metre thick permeable erosion resistant cap over all contaminated materials. This design allows for the installation of a geomembrane in the future if groundwater monitoring should indicate contamination. Notably, the plan required a change to the Hazardous Waste Regulation to allow for the construction of an in situ management facility, and in 2012 an approval was issued by the Ministry of Environment, the first of its kind in BC.
Upon receipt of approvals, hazardous wastes from the buildings, including fuel, chemicals and asbestos building materials, was removed to an off-site disposal facility. The mill building and equipment were then demolished, compacted and capped within the original footprint and adit water was diverted around the landfill area. The cap also covered the tailings pond, sedimentation pond and high-risk contaminated areas on the mill pads. Local borrow sources were used for capping materials and the area was reclaimed, incorporating the natural topography of the site. Revegetation plans are now currently under development and monitoring of cover performance and water quality will continue to be requirements for the site.
Work at the Atlin Ruffner site resolved contaminated site issues using cost-effective, remediation techniques. All parties involved are commended for their excellent work in addressing historic contamination issues and reducing the associated risk to public health and safety.
Ryan Mills, AECOM Canada came forward to accept the award for outstanding Metal Mine Reclamation of the Atlin Ruffner Mill and Tailings, on behalf of the BC Crown Contaminated Sites Program of the Ministry of Forests, Lands and Natural Resource Operations and AECOM Canada Ltd.
L-R Dave Nikolejsin, Deputy Minister, Ministry of Energy and Mines, Ryan Mills, AECOM and Jaimie Dickson, 2013 Chair of TRCR
LAST YEAR’S WINNER
The keeper trophy for last year’s recipient of the Annual British Columbia Jake McDonald Mine Reclamation Award was presented to the Tsolum River Partnership for their outstanding efforts to reclaim the historic Mt. Washington mine site. This large-scale reclamation project was the result of a unique partnership that involved many people and agencies working together to mitigate the impacts of acid rock drainage on a large salmon fisheries resources. The installation of a liner significantly reduced copper loadings and has improved water quality to the point that aquatic habitat and salmon resources are beginning to recovery in the lower Tsolum River watershed.
As none of the current members of the Partnership were able to attend, a former participant of the Partnership, Ben Chalmers accepted the keeper trophy for the Tsolum River Partnership.
Ben Chalmers, previous Participant in the Tsolum River Partnership accepting the keeper trophy from Dave Nikolejsin, Deputy Minister, Ministry of Energy and Mines
2013 TRCR Members
L-R TRCR Committee: Dirk VanZyl, UBC; Carla Fraser, Teck Coal; Darren Cowan, Hillsborough Resources; Jaimie Dickson, Highland Valley Copper and 2013 Chair of TRCR; David Ewing, MABC; Ryan Todd, New Gold and 2014 TRCR Chair of TRCR; Jonathan Buchanon, AMEBC, Kim Bellefontaine, MEM; Wendy Gardner, Thompson Rivers University; Kim Bittman, Taseko Mines, Ben Chalmers, Mining Association of Canada, Tania Demchuk, MEM; and Bill Price, NRCan.
Missing: Nicole Pesonen, Walter Energy and Vice Chair of the TRCR; Craig Stewart, MOE, Todd Wambolt, Gibraltar Mines, and Angela Waterman, MABC.