Mine Closure Case Study

We believe that how we close a mine is just as important as how we open and operate a mine. Our commitment to excellence in mine closure is demonstrated by our highly successful and award-winning approach to closing two of our historic flagship projects, the Duthie and Silver Standard mines in British Columbia, Canada. These mines are important parts of our company’s history and the positive environmental legacy we have left at the mines is a reflection of our commitment to delivering excellence in mine closure.

The Silver Standard mine was the first mine owned and operated by SSR Mining (formerly Silver Standard Mines Ltd.). The mine reflects our company’s origins and our over 70-year history as a producer of precious metals.

The mine was located approximately seven kilometres north of Hazelton in northern British Columbia. To reclaim the former tailings facilities, we collected the oxidized tailings and placed them in a high-density polyethylene-lined repository to prevent further oxidation.

To mitigate the potential impacts of non-oxidized tailings, we constructed an engineered cover system. The cover – or “wet blanket” – is composed of a variety of organic and inorganic materials, including sawdust, gravel, soil, and coconut-bamboo vegetation blankets to ensure that the remaining tailings do not oxidize.

The Duthie mine was located on the southwest slope of Hudson Bay Mountain, approximately 13 kilometres west of Smithers in northwest British Columbia. The mine was in operation intermittently during the 1920s to 1950s and again during 1984 to 1988.

We developed a comprehensive closure plan in conjunction with the British Columbia Department of Mines and the Ministry of Environment. The key focus of the plan was the remediation of mine tailings, which, historically, were largely unconfined.

As part of the plan, we used a capping and ditching technique to reclaim the tailings site, capturing water run-off into a passive treatment system. We also developed a comprehensive water quality monitoring plan – which we continue to implement today – to help ensure that we mitigate potential impacts to local water quality.

In recognition of our efforts and success in closing the mine, we received recognition for Outstanding Reclamation Achievement by the Technical and Research Committee on Reclamation from the Mining Association of British Columbia and the British Columbia Ministry of Energy and Mines.

Delivering excellence in mine closure is an important part of our legacy. We will continue to work diligently to deliver on this commitment for all of our stakeholders