Hecla Mining Company wants to expand the tailings disposal facility at its Greens Creek Mine near Juneau in order to extend the life of the mine an additional 30 to 50 years.
The mostly lead, zinc and silver mine is located about 18 miles southwest of the Capital City on northern Admiralty Island, and is Juneau’s largest private employer with 370 full time workers.
Greens Creek Environmental Manager Jennifer Saran says the mine was expected to have a lifespan of 10 years when it started operating 23 years ago.
“Here we are, over 20 years later, we’re still here, we’re still operating, and we still have a 10 year mine life,” Saran says.
Tailings are the materials leftover after valuable minerals have been extracted from ore during the mining process. Saran says about half of Greens Creek’s tailings are combined with cement and used as fill to support mined out areas underground. The rest are stacked at a dry tailings facility located a few miles from the mine portal.
The dry stacked facility will run out of room in two years unless the mine is allowed to expand its tailings footprint. So in 2010, Hecla proposed an expansion to the south, which would hold an additional 9.7-million cubic yards of tailings.
Because Greens Creek is within the Admiralty Island National Monument, the U.S. Forest Service is conducting a National Environmental Policy Act review of the proposal. On April 20th, the agency released a draft Environmental Impact Statement for the project.
As typically is the case for such reviews, the EIS included four possible alternatives: No action, or no expansion of the tailings facility; The mine’s proposal to expand the existing facility; an option to build a separate dry tailings facility a few miles from the current one; and the last option, which would combine alternatives two and three.
Saran says mine officials believe option two – expanding the current facility – is the best.
“We believe that keeping one tailings disposal facility allows us to keep all of our eggs in one basket, so to speak,” says Saran. “We can monitor, we can operate, and we can close for reclamation one facility rather than numerous facilities.”
Saran made her presentation at last night’s CBJ Assembly Committee of the Whole meeting. Assemblyman Jesse Kiehl asked why the mine doesn’t just continue to stack tailings at the current disposal site. Saran said some additional stacking could occur, but if the mine continues to find new reserves, the facility will need to expand at some point.
“That’s actually one of the benefits to our proposal. Keeping them at the same site allows a smaller footprint for the expansion, because we can go higher,” Saran says. “Building a new facility would mean a larger footprint. We can’t go extremely high for geotechnical stability reasons. But we can go higher than we are currently.”
The Forest Service’s draft EIS is currently out for public comment through June 4th. Once all of the comments have been taken and analyzed the agency will issue a final EIS and Record of Decision, likely in November.
Link:
Greens Creek Mine Tailings Disposal Facility Expansion Draft EIS [PDF]
