The Arctic Gold and Silver Mine Site located on Montana Mountain near Carcross, Yukon (the Site) operated during the late 1960's. After mining operation was ceased in 1969, there remained potential environmental issues with regards to the tailings that had accumulated at the Site during mine operation. A potential environmental issue associated with these tailings is the possibility that Acid Rock Drainage (ARD) could occur.
To ensure that ARD reactions do not occur in the future at the site, the federal government (with assistance from consultants) developed a reclamation plan for the tailings at this site. A silty clay material was used to cover the tailings to prevent oxygen and water from entering and reacting with the iron-sulphides to produce ARD. EBA Engineering Consultants Ltd., the Carcross Tagish First Nation and partners, on behalf of Mining Environment Research Group and Indian and Northern Affairs Canada, conducted a study to evaluate the performance of the silty clay cover over a tailings impoundment at the Site between September 2000 and January 2001.
Data-gathering equipment was installed at the Site. Three rounds of testing and monitoring at the site were completed to gather data regarding the thickness, oxygen concentrations, temperatures and moisture levels within the tailings and the cover.
This report presents the conclusions and recommendations of the study::
- Observations show that the cover system was installed properly and according to the design
- Preliminary data show that the cover is working to reduce the amount of moisture and oxygen entering the tailings
- It would be valuable to collect more data at the Site to observe trends and see how well the cover systems will work over time in a northern climate.
