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Helena, EPA say no impact to city water after mine waste spills into Tenmile Creek

Tenmile Spill
Tenmile Spill
Posted at 10:51 AM, Jul 14, 2021
and last updated 2021-07-14 13:01:25-04

HELENA — The U.S. Environmental Protection Agency (EPA) says only about 100 feet of Tenmile Creek were affected by the release of sludge from a mine in Rimini.

Chris Wardell, community involvement section chief for the EPA, said in a statement that a small amount of sludge – about 20 to 40 gallons – was released Monday from the Susie Mine.

He said crews had been using a hose to suck up water from inside the mine tunnel, when the hose accidentally picked up excess sediment and sludge.

“The sludge exited the Susie Adit draining to Tenmile Creek in a manner similar to many previous discharge events or ‘burps’ over the past century in this heavily mined and mineralized area,” Wardell said.

The EPA and Montana Department of Environmental Quality (DEQ) determined this “dewatering” operation was needed because of a collapse that occurred in the mine months ago.

“This collapse caused a blockage of mine-impacted water within the tunnel, which without action to remove mine-impacted water and prevent further degradation of the mine entrance, increases the risk of an uncontrolled release to Tenmile Creek,” said Wardell.

EPA leaders plan to resume dewatering in the next few days, and to install additional control measures to try to keep sludge releases like this from happening.