Copper mining company Montana Resources is now one step away from receiving approval from state regulators to expand its permanent mine tailings storage facility in Butte.
Since 1986, Montana Resources (MR) has been sending the slurry of waste from its open pit copper and molybdenum mine in Butte up to the Yankee Doodle Tailings Impoundment, which sits uphill and northeast of the Berkeley Pit.
But MR’s VP of Environmental Affairs Mark Thompson says they need more space to store waste. Otherwise, at their present pace of operation, "We would run out of tailings storage capacity in 2021. If you don’t have any place to put tailings, you can’t mine."
Last year, MR got preliminary approval from state regulators to expand the tailings impoundment and build it 50 feet higher, which buys them another 10 years of waste storage. That requires an amendment to their mining permits.
On Wednesday, the Montana Department of Environmental Quality (DEQ) released their final 351-page Environmental Impact Statement, which supports MR’s proposed action.
"You know, in 2015, state legislators set an exceptionally high bar for operators of tailings storage facilities in Montana," Thompson says. "And we’re just really glad that DEQ has recognized that we’re meeting and often exceeding that high standard that the Legislature established."
When the mine eventually closes, in maybe three decades or more, DEQ would like to see MR reclaim Yankee Doodle on a slightly faster timeline than what the company is currently planning. That would mean a change in how they treat water there.
But here’s where it gets more complicated. The tailings impoundment is also part of a Superfund site that includes the Berkeley Pit. And Karen Ogden with DEQ says under Superfund law, one party can’t just unilaterally require changes to water management — like dealing with water seeping out of the tailings impoundment.
"However, DEQ did add a stipulation to the final EIS that Montana Resources work with their Superfund partners, within a certain timeframe, to identify options to address the seepage. And that’s important because those measures could result in earlier reclamation," Ogden says.
Now that the EIS is finished, DEQ says it will issue its final decision on MR’s request to amend their mining permits and expand the Yankee Doodle Tailings Impoundment by August 30.
Find more info, including the final EIS: http://deq.mt.gov/Public/eis