After extracting the gold, wet tailings resembling silt will be a byproduct of the milling process. A containment dam, engineered to withstand environmental events and changes typical of Alaska, will be built to house the tailings.
The tailings storage facility contained within the dam will have a 60-mil. (.06-inch), textured, linear, low-density, polyethylene liner. The ultimate size of the facility will be approximately 1.75 miles long by 1 mile wide. This preventative measure is not required under state mining regulations and demonstrates the high level of environmental stewardship Donlin Gold brings to the project.
When the mine is no longer in operation, the tailings-storage facility will be covered with rock, gravel and soil, planted with vegetation, and re-contoured to blend in with the surrounding terrain.