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EPA says no impact to Helena water after mine waste spills into Tenmile Creek

mine waste spills into Tenmile Creek
Posted at 1:43 PM, Jul 13, 2021
and last updated 2021-07-14 11:52:08-04

HELENA — The city of Helena and the U.S. Environmental Protection Agency say there will be no impact to the city’s drinking water supply, after material from an abandoned mine spilled into Tenmile Creek near Rimini.

Ryan Leland, Helena’s public works director, says city water operators received a report Monday about mine waste in the creek. They determined it came from the Susie Mine, a previously treated mine in the area.

The city of Helena takes much of its drinking water from the Tenmile Creek watershed. However, that water is removed from the creek upstream from the Susie Mine, and carried down to the water treatment plant through a pipe system.

“It’s never actually going to get into our drinking water, but it is in the watershed, and we’re concerned just with regular water quality and for other water users in the area,” said Leland.

An EPA spokesperson confirmed the event should not impact Helena’s water supply, and noted it happened in a section of the creek that has been receiving contaminated material for more than a century and is targeted for future remediation.

Tenmile Spill
Tenmile Creek near Rimini, July 12, 2021, after material from an abandoned mine reportedly spilled into the creek.

The area around Rimini is managed by the EPA as the Upper Tenmile Creek Mining Area, a Superfund site. It covers 53 square miles and includes about 150 active or abandoned mines. Mining for gold, lead, copper and zinc extended from the 1870s to the 1930s.

Over the last 20 years, authorities have removed contaminated soils from many nearby properties, set up new water systems for residents, and installed systems to limit outflows from area mines.

According to government reports, the Susie Mine had originally been one of the main sources of arsenic and other contaminants in the watershed.

Photos taken by city staff show a section of the creek turned orange after the spill. However, city leaders say they have no confirmation yet of what type of substances may have been in the spilled material.