Greens Creek Mine Tailings Storage Facility | Alaska, US
Located in southern Alaska, Admiralty Island is home to a large brown bear population, as well as bald eagles, whales and salmon. The island is home to the 955,000-acre Admiralty Island National Monument, a lush rainforest that draws many tourists. Part of the Hecla Greens Creek polymetallic mine is located within the monument.
Hecla Greens Creek Mining Company asked Klohn Crippen Berger (KCB), a Louis Berger affiliate, to develop solutions for storing de-watered tailings in a sensitive regulatory site while preserving world-class tourist attractions. Minimizing views of the site from cruise ships was also necessary. The challenge was to design and build a tailings disposal facility that would meet these requirements and oversee its geotechnical operation.
KCB designed and created the world’s first and longest-running dry stack filtered tailings disposal system. Project hallmarks include:
- Dry stacks of tailings that can withstand static and seismic forces.
- Reduction of footprint of tailings by more than 50% with no pond needed.
- The free and safe roaming of wildlife, including brown bears.
The tailings disposal facility was designed to divert surface and ground water away from the tailings stack. Internal drainage structures incorporated in the construction of the dry stacks promote low water tables. Water coming in contact with tailings is contained and treated to meet water quality standards before being discharged into the environment.
Mining employs more than 1,500 people in Alaska and is under intense scrutiny for safety and environmental impacts. Careful yet rigorous tailings disposal benefits the mine operation, local jobs and Alaskan wildlife.