A company that is potentially interested in re-mining the abandoned Gilt Edge gold mine could re-disturb areas that have been reclaimed as part of a $120 million cleanup project during the past 18 years.
That acknowledgement came from Gregg Loptien, the U.S. exploration manager for Canada-based Agnico Eagle Mines, during a tour of the mine site Wednesday that was attended by several Agnico officials, representatives of the state and federal government, local environmental activists and the media.
Loptien was asked if some of the completed reclamation work will be undone if Agnico ends up re-mining the site.
“At this point in time, we can’t be certain,” Loptien said.
He added, “We’ve got a lot of questions to answer for ourselves before we ever even make a decision to do anything out here.”
It’s estimated that an additional $88 million worth of reclamation work is currently needed at the site, and Loptien said Agnico would absorb that cost and the responsibility for the cleanup if the company finds enough recoverable gold and is granted the necessary mining permits.
“If it’s economic, you bet,” Loptien said.
Last year, Agnico struck a deal with the U.S. Environmental Protection Agency that could determine the future of the Gilt Edge Mine.
Under the terms of the deal, Agnico has begun drilling up to 18 holes on the mine site ranging from 700 to 2,700 feet in depth, to help the EPA pinpoint the mysterious source of toxic cadmium contamination showing up in Strawberry Creek.
In exchange for conducting the drilling and cadmium investigation, Agnico will be allowed to analyze core samples to determine whether there is enough recoverable gold at the site to re-mine it.
The EPA and Agnico are describing the project as a win-win-win, because the EPA will get information about the cadmium problem without paying for it (Agnico officials have budgeted $5 million for the project), while Agnico could eventually reap financial benefits from re-mining the site, and the burden of funding the cleanup could be shifted from taxpayers to Agnico.
Yet, as an EPA official and several Agnico officials were talking hopefully about the future Wednesday, they were standing amid the barren wasteland left behind by the mine’s previous operator, Brohm Mining, which abandoned the mine only 19 years ago.
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The mine's past has inspired skepticism in David Miller, the Rapid City activist who requested Wednesday’s tour.
“I think there’s a lot of discussion coming up in the future, is what I’m thinking,” Miller said. “It’s going to be pretty serious stuff.”
The mine site is a 360-acre gouge in the northern Black Hills, about 5 miles southeast of Lead. Mining at the Gilt Edge began in 1876 and continued intermittently until 1999, when Dakota Mining, the corporate parent of Brohm Mining, declared bankruptcy in Canada.
Brohm used the heap-leach method of gold mining. Ore and waste rock were excavated from large pits, and the waste rock was dumped into a gulch while the ore was crushed and piled in a heap. Cyanide was used to leach the gold from the heap of crushed ore.
When Brohm abandoned the mine, the pits on the site contained a combined 150 million gallons of acidic water laden with contaminants such as lead and arsenic.
In 2000, the EPA added the mine to its National Priorities List, which made the site eligible for money from EPA’s Superfund. Studies and cleanup work have been ongoing ever since at the mine, which is now mostly state-owned.
The amount of acid water on the site has been reduced to 50 million gallons. But water treatment is ongoing, because precipitation and groundwater at the site are continually contaminated by exposed minerals. During treatment, the contaminants are removed and the low pH of the water is raised to make the water safe for aquatic life in Strawberry Creek, which flows into Bear Butte Creek.
Water formerly collected in three large pits on the site, but two of the pits have been filled. The third pit is being used as a collection basin, where water pumped from elsewhere in the mine is stored before it is pumped to the treatment plant.
A waste rock dump, known as the Ruby Repository, has been graded, terraced and covered. Grass now grows atop the repository, where the waste rock is buried under a plastic barrier topped by several feet of earth.
Unless the mine is reopened by Agnico, EPA eventually plans to fill the third pit, build plastic-lined water holding cells at the current site of the heap leach pad, and recover most of the mine area with vegetation.
Joy Jenkins, the EPA official who led Wednesday’s tour, said the future work could take eight to 10 years depending on the availability of funding from Congress. Estimates produced in 2014 indicated that the remaining work will cost $88 million, Jenkins said, which would raise the total cost of the reclamation project beyond $200 million.
Much of the money so far has come from the federal government, although settlements with past operators of the mine have recouped about $40 million, and the state of South Dakota has contributed more than $6 million as part of its mandatory match for certain Superfund costs.