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Plans To Pump, Treat Berkeley Pit Water Move Forward

The Berkeley pit in Butte, Montana, as seen from above.

The mining companies in charge of the Berkeley Pit are going to start pumping, treating and discharging the water in the former open pit copper mine into Silver Bow Creek five years earlier than planned. Susan Dunlap is reporting that story for the Montana Standard in Butte. She spoke to MTPR's Nora Saks.

Nora Saks: Susan Dunlap, thanks so much for joining us on Montana Public Radio to talk about the Berkeley Pit.

Susan Dunlap: Thank you for having me Nora.

NS: Earlier this week you reported there was a big announcement from the companies that manage the Berkeley Pit in Butte. What did Montana Resources and Atlantic Richfield have to say?

SD: They want to start a pilot project where for the next 3-4 years, they’ll be pumping and treating Berkeley Pit water. This is 5 years ahead of schedule, so this is quite a big announcement.

NS: You said it’s five years ahead of schedule. What was that date in 2023 - why was that significant?

SD: The agencies initially, when they created the clean up plan for the Berkeley Pit, established 2023 as the critical, as the point at which the groundwater in the mine shafts would reach critical water level. Which is 5,410 feet. Once that hit, then it was necessary for the pit to be pumped and treated. There was always some cushion added into the system, but the community has long feared that the Horseshoe Bend water treatment plant wouldn’t be ready on time.

Credit Nora Saks
Susan Dunlap is reporting the story for the Montana Standard. "This is 5 years ahead of schedule, so this is quite a big announcement," she said.

NS: Why did they decide to speed up the process and get ahead of schedule? Where did this idea come from?

SD: The plan came from Montana Resources. Some of it is because they need to decrease the water level in Yankee Doodle Tailings Pond. But I think they also are responding at least to some degree to the community’s fears. What Mark Thompson, the Vice President of Environmental Affairs for Montana Resources, said to me was that for 30 years they’ve been watching the Berkeley Pit control groundwater. Now it’s time for them to control the Berkeley Pit.

NS: Can you describe how this is going to work? Where is all the water and the toxic metals in the water going to go?

SD: It’s a complicated process and it loops all around through the mine system. So initially the water will be pumped out of the Berkeley Pit and it will go through a recovery plant and it will be treated at Horseshoe Bend Water Treatment Plant and the metals will then be dropped out through that process. Montana Resources expects to recover the copper for profit. Then it will go through the mill workings and on out to Yankee Doodle tailings pond along with some other water. And Yankee Doodle tailings pond has two components. There’s an area called the beach, which is kind of where the muck is, and the waste rock. But then the water kind of drifts out and there’s what they call a clear water pond on the north end of it. Beavers live in that pond and the water quality in that part of the pond is relatively ok and still needs a little bit of work. But they’re going to build a polishing plant as well as a discharge facility. And the polishing plant will take care of the water that comes from the pond and make sure that there’s no sediment with contamination attached to it. And there’ll be some sort of filtration system to make sure it meets water quality standards.

NS: What kind of volume are we talking about here? How much toxic water does the Berkeley Pit currently hold and how much are they planning on treating every day?

SD: Currently it holds around roughly 50 billion gallons of contaminated groundwater. What they’re planning to do is discharge, once they start, about 7 million gallons a day. Which equal to about 11 cubic feet per second.

The Berkeley Pit in Butte
Credit Mike Albans
The Berkeley Pit in Butte, Montana.

NS: The water that is going to be discharged is going to affect upper Silver Bow Creek which is that reach of stream downstream of the Berkeley Pit in Butte. What are the anticipated effects on Silver Bow Creek?

SD: It’s going to be discharged at the confluence of Silver Bow Creek and Blacktail Creek. At least so far, there’s no clear plan in place to discharge it at Texas Avenue, which is what many people in the community hope to see. But that hasn’t been 100 percent ruled out in the long term. But in terms of what it will mean for the creek, so far everyone I’ve spoken with says it’s nothing but good news. Additional water that meets water quality standards is just by nature going to be good news for the creek. It puts more water in there. It’s better for the fish. It’s better for the habitat. So far I’ve not heard a single critic.

NS: Anything else you want to add?

SD: I think this is really exciting news for Butte and I’m really excited that I’ve been able to report on it.

NS: Susan Dunlap thanks so much for chatting with us about the Berkeley Pit today.

SD: Thank you so much Nora for having me.

Nora Saks is a reporter and producer based in Butte, MT.
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