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Sloughing, water level among residents’ concerns

The stability of the Berkeley Pit and the future of its toxic contents were the primary concerns people had at a public hearing Tuesday evening about Butte’s mega Superfund site.

People listened to representatives from environmental and other agencies about the rising water level of the pit, its structural soundness and asked if there was any threat to the community.

The meeting was called at the Butte Public Archives just over a week ago after people had concerns over recent landslides from the pit’s walls that caused waves in the pit water.

Sara Sparks, remedial project manager with the Environmental Protection Agency in Butte, assured the public there is no danager of the pit water breaching its walls and flooding the community.

“We feel human health and the environment are safe,” Sparks said.

However, some of the more than 80 audience members weren’t comforted by this assurance. Cindy Perdue-Dolan said she was

disappointed that the public wasn’t informed by the EPA about these pit wall slides until they came out in a recent article in The Montana Standard. It was learned that there were three slides in the Berkeley Pit in about a six-month period, with the last slide occurring onFeb. 8.

Sparks apologized for not making these incidents public, and promised that she will report any future sloughing of the pit walls to the local media.

The panel of representatives all agreed that the slide-offs were relatively minor — with the February one displacing about one foot of pit water.

Still, the pit water is rising.

Though the audience remained polite, some asked direct questions about what was being done about the rising water. Daryl Reed with the Montana Department of Environmental Quality explained that the pit water will reach the “critical water level” in about 10 years. Still, Reed said the critical water level is 140 feet below the rim of the pit.

Some people were quick to note that 140 feet didn’t seem like a comforting level from the rim of the pit.

It’s at this critical level that the pit water will have to be sent through a water treatment plant to remove its acidity and make it environmentally safe. Reed said after the pit water is treated, it would likely be released into Silver Bow Creek.

Audience member John Ray asked if minerals in the treated pit water could turn the creek white. The EPA said that would require more research.

The Berkeley Pit is maintained jointly by Montana Resources, which mines in that area, and former pit operator Atlantic-Richfield Co. (ARCO). The pit was actively mined from 1955 to 1982. When ARCO ceased operations in 1982, it shut off the pumps that kept ground water out of the mines, and the water has poured back into the pit ever since.

This begged a simple question from some in the audience to the environmental groups: Why did you wait?

People wanted to know why action wasn’t taken sooner if it was known the pit will continue to fill.

Sparks noted that under Superfund laws, there are many regulations to consider. However, she first pointed out that the expense of treating the water is a factor.

“We did have to take that (cost) into consideration,” Sparks said.

Sparks tried to reassure the people that the EPA wouldn’t let expense prevent it from addressing environmental problems.

Montana Resources spokesman Tad Dale also addressed the wall sliding issue. He said the slides were only occurring in the southeast corner of the pit, which is mostly made up of clay and sandy material. The alluvial soil was once part of Silver Bow Creek, which ran through there before being taken out by the pit.

Dale said the slides are no reason for the public to be alarmed.

“It is naturally going to be unstable,” he said about the alluvial soil. “In a mine, you have slope failures all the time.”

He added that the rest of the pit walls are cut from bedrock and are stable.

Montana Resources is monitoring the unstable wall on a daily basis, according to Dale.

Nick Tucci with the Montana Bureau of Mines and Geology said he monitors the ground water and there is no concern of the pit water breaching the rim of the pit.


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