Effluent & Waste Management
Mining inevitably produces waste products ranging from waste rock and tailings (a by-product of mineral processing), to air emissions from mobile equipment and other sources, camp refuse, hazardous materials, and potential sources of pollution. Managing waste is therefore fundamental to protecting water, biodiversity, and other aspects of the environment. We dispose of our waste products on- and off-site, depending on the product and available facilities.
Our approach to effluent and waste management is defined in our overall environmental management system as described in Environmental Management. Specific management plans that pertain to effluents and waste management include the Tailings and Subaqueous Waste Rock Deposition Management Plan, Spill Response Plan, Water Management Plan (as detailed in Watershed Management) and the overarching Waste Management Plan. Pretivm’s COO and VP of Environment and Regulatory Affairs have accountabilities for tailings and mine waste management at the Brucejack Mine, reporting to our CEO and Board of Directors. Other aspects of environmental and waste management are led by our VP of Environment and Regulatory Affairs. The Mine General Manager and Manager of Environment and Regulatory Affairs are responsible for implementation at the site, and for communicating incidents, risks, and opportunities for improvement in a timely manner.
Mine Waste & Tailings Management
Mine tailings management is a topic of significant interest to regulators, investors, media, Indigenous groups, and the public, and the reputation of the mining industry has been challenged by examples of poor tailings management (specifically, tailings dams) in recent years. At Pretivm, our management of tailings and mine waste is a priority, from the earliest design stages and throughout the mine life.
The Brucejack Mine is unique in that it does not include a conventional tailings dam, tailings pond, or surface waste rock piles. We avoided these features and the associated risks of dam failure and long-term maintenance requirements after closure by designing the Mine around attributes of the natural landscape. Our Waste Rock and Tailings Storage Facility (WRTSF) was built within a deep, high-elevation, and non-fish-bearing lake. Where possible, we deposit waste rock and tailings from the Brucejack Mine as backfill in the underground mine, and we submerge the remainder of waste rock and tailings in the WRTSF. Unlike many gold mines, we do not use cyanide in the gold extraction process, so we avoid many of the hazards associated with cyanide management.
There are no fish in the water bodies adjacent to the Mine or WRTSF, and nearby water bodies are naturally high in dissolved metals from the surrounding geology. The WRTSF has a single outflow, which allows us to carefully monitor water quality to ensure it meets strict water quality standards required for discharge to the environment. We track the concentration of metals and other water chemistry parameters in a number of locations including within the WRTSF, at the outflow, and downstream. More information about how we protect water quality is provided in Watershed Management.
Pretivm recognizes the importance of responsible tailings management throughout and beyond the life of the Mine. Our approach greatly reduces risk to the environment and liability to Pretivm associated with mine waste, as waste rock and tailings will remain submerged at depth with no requirement to maintain a dam or containment structure. This effectively eliminates the critical health and safety risks associated with conventional tailings dams and storage facilities, while also preventing acid rock drainage and airborne emissions of fine particulates that are associated with other forms of tailings management.
Operation of the WRTSF is governed by an operation management system and is subject to an annual independent technical review. In addition, we manage the potential risks of metal leaching and acid rock drainage associated with storage of waste materials through our Metal Leaching and Acid Rock Drainage Management Plan.
Annual WRTSF Highlights
In 2020, we mined 1,377,912 tonnes of rock from our underground mine, producing 786,000 tonnes of waste rock and 1,229,000 tonnes of tailings. A portion of the tailings (35%) was used as paste backfill in the underground mine, and the remainder (797,000 tonnes) was disposed in the WRTSF. As a result of increased production levels at the Mine, the volume of waste rock and tailings disposed in the WRTSF increased modestly over 2019 levels, with a 1.7% and 2.0% increase in tonnage of waste rock and tailings, respectively.
In 2020, we commissioned a third-party review of our WRTSF management practices in our efforts to continually improve our management of mine waste and the WRTSF. We are acting on the recommendations from this review in 2021, including changes to governance and oversight to strengthen our approach in line with industry best practices.
At the Brucejack Mine, we manage air emissions through our Air Quality Management Plan and associated monitoring programs. We are proud to have had no exceedances of air discharge permit limits since the beginning of operations.
Pretivm reports annually to the National Pollutant Release Inventory program for criteria air contaminants including carbon monoxide, nitrous oxides (NOX), sulphur oxides (SOX), and particulate matter (including dust). Since 2018, our annual emissions have generally increased due to rising production levels at the Mine. Our annual emissions data is available in our analyst download. Greenhouse gas emissions are described in Energy & Climate Change.
Other Waste Products
Refuse & Recycling
Our Waste Management Plan governs the handling, reuse, recycling, and disposal of various types of waste at the Brucejack Mine. We separate refuse into different streams for recycling and disposal, including waste materials from kitchens and offices, workshops, maintenance yards, and other facilities. Waste streams include general refuse, cardboard, plastics, metals, burnable wood, non-burnable wood, electronics, and hydrocarbons. Our on-site waste management department is responsible for the program and aims to maximize recycling and reuse, and minimize the volumes of waste transported off-site for disposal.
At the Brucejack Mine, we consolidate scrap metal, which is re-used by a contractor. We recycle cardboard and domestic recyclable materials. We incinerate burnable wood and domestic refuse at the site, and transport non-burnable wood for off-site disposal. All employees receive instruction in the waste management program so that they know how to handle and dispose of different waste products.
In 2020, we transported 1,113 tonnes of non-hazardous waste off-site to authorized regional recycling and waste facilities in BC. Of the total non-hazardous waste, 855 tonnes (39% of total non-hazardous waste) were recycled. This marks a substantial increase from the proportion designated for recycling in 2019 as a backlog of tin and scrap metals from a previously decommissioned exploration camp were recycled in 2020.
Sewage & Wastewater Treatment
An on-site sewage treatment plant at the Brucejack Mine treats sewage, and treated effluent is discharged to the WRTSF. The treated effluent is monitored to confirm water quality standards are achieved prior to discharge. In 2020, we added an additional sewage treatment unit to provide fully redundant capacity for the Brucejack Camp’s sewage needs. In addition to the sewage treatment plant, our on-site water treatment plant treats runoff water collected from the surface mine site and in the underground mine. As described in Watershed Management, we recycle treated water in the mill.
Hazardous Materials Handling & Disposal
Handling of hazardous materials (such as diesel fuel and hydraulic fluids) is a necessary part of our day-to-day activities. We track, manage, and measure all hydrocarbons stored and handled at site as part of the overall environmental management system, which clearly assigns responsibilities for tasks such as fuel-level tracking. In 2020, we used 8,675,341 litres of diesel and 272,184 litres of gasoline at the Brucejack Mine. Our combined fuel consumption increased by 17% as a result of increased mine production rate and interruptions to the supply of hydroelectricity.
We contract a licensed external company to transport and properly dispose of hazardous waste products. These products range from oily rags and paint containers to excavated soil that has been contaminated by a spill. In 2020, the Brucejack Mine produced 614 tonnes of hazardous waste materials that were disposed at appropriate off-site facilities including used batteries, used oil, used coolant, hydrocarbon contaminated material and soil, and sludge from our on-site sewage treatment and septic facilities. The volume of hazardous waste materials for disposal increased by 57% over 2019 volumes. This increase is attributed to the disposal of approximately 200 tonnes of hydrocarbon contaminated materials and soil.
Spill Prevention & Response
Spill prevention is something we proactively promote every day and integrate throughout our management plans and practices. In 2020, we updated our Spill Prevention and Response Plan to address learnings from past spills, including expected preventative and responsive measures. We also contracted a third-party company with extensive spill response experience to facilitate spill response training at the Brucejack Mine.
Our environmental management system includes standards of practice for activities such as fueling, materials handling and transportation, mechanical works, and other activities that could lead to a spill. While we prefer to focus on prevention, we also ensure that we are prepared to respond when needed. All of our workers receive training in spill response so that they can quickly take action if a spill (or other unplanned release) does occur.
Pretivm recorded no significant spills1 in 2020. If a spill exceeds a substance-specific threshold, we are obligated to report it to provincial authorities (“reportable spills”) but in practice, we record and report every spill internally. Our spill reports document the time and place, cause of the spill, response measures, and new measures created to prevent a reoccurrence in the future. Site managers report this information (for both reportable and non-reportable spills) to Pretivm’s senior management and the Board of Directors.
tonnes of non-hazardous materials of waste recycled
of all non-hazardous wastes recycled
decrease in reportable spills from 2019 to 2020
With 10 years of experience in the mining industry, Harrison Mazur brings a wealth of knowledge to his role as Environmental Scientist. An outdoor enthusiast in his spare time, he speaks from personal experience when teaching people about the wildlife around the mine and how to have safe interactions. This ranges from bears wandering into camp to swallows diving at people’s heads to protect their nests. At the Brucejack Mine, reclamation does not start after the end of mining but is a continuous process of progressive reclamation throughout the Life of Mine. A highlight for Harrison is watching the reclaimed areas come to life and seeing nature regenerate in cleared areas. Apart from his work on the environmental team, safety is an important part in both his personal and his work life. The experience he has gained as a volunteer fire fighter in his home community of Telkwa can be directly applied to his leadership role on the Brucejack ERT team where he provides training and mentorship to the other team members as the team expands and takes on new challenges.
Taking a Leadership Role Across Teams
With 10 years of experience in the mining industry, Harrison Mazur brings a wealth of knowledge to his role as Environmental Scientist. An outdoor enthusiast in his spare time, he speaks from personal experience when teaching people about the wildlife around the mine and how to have safe interactions. This ranges from bears wandering into camp to swallows diving at people’s heads to protect their nests.
At the Brucejack Mine, reclamation does not start after the end of mining but is a continuous process of progressive reclamation throughout the Life of Mine. A highlight for Harrison is watching the reclaimed areas come to life and seeing nature regenerate in cleared areas.
Apart from his work on the environmental team, safety is an important part in both his personal and his work life. The experience he has gained as a volunteer fire fighter in his home community of Telkwa can be directly applied to his leadership role on the Brucejack ERT team where he provides training and mentorship to the other team members as the team expands and takes on new challenges.