The U.S. Forest Service has issued its final supplemental environmental impact statement and draft record of decision to allow expansion of the Kensington Mine, about 35 miles south of Haines. The expansion would extend the mine’s life to 2033.

The project would include raising the height of the tailings treatment dam by 36 feet to store more waste rock from the mining operation, and constructing a 40-foot-high back dam between the tailings treatment facility and Upper Slate Lake, which would almost double the tailings disposal capacity to 8.5 million tons.

The project also includes expanded storage for waste rock at the mining site, and construction of a new waste rock storage site on the property. Together, that would add an additional 5 million tons of storage capacity.

The underground gold mine has operated since 2010 at the site on a peninsula between Lynn Canal and Berners Bay, and had projected a 2023 end date for operations unless granted approval to expand its waste rock storage.

As part of the expansion project, the mine operator will construct a new stream channel to reroute Fat Rat Creek into South Creek and add Dolly Varden char spawning habitat by constructing two deltas.

The entire project includes constructing 1.75 miles of new access roads and disturbing 128 acres of Forest Service land.

The release July 8 of the final report and draft decision begins a 45-day objection period, but it is open only to those who submitted comments earlier in the Forest Service review process.

“The Forest Service recognizes the importance of mineral resources and encourages safe, responsible mineral exploration and development as part of our multiple-use mandate,” Earl Stewart, Tongass National Forest supervisor, said in a prepared statement announcing the decision.

“My decision considered that … the overall operations would be virtually the same as their current operations. This carries some weight because the mine is experienced in operating this project and meeting environmental requirements,” Stewart said in his decision.

Project information and documents are posted on the Forest Service web page: https://www.fs.usda.gov/project/?project=55533, or contact Matthew Reece at 907-789-6274, or [email protected].