CURRENT WATER LEVEL: 5,272.94 ft

PitWatch.org is the Web version of PitWatch, published by the Berkeley Pit Public Education Committee (see below).

Our purpose is to educate Butte residents and students about the Berkeley Pit and surrounding underground mine-flooding areas.

The most recent edition of PitWatch commemorates 25 years since the pumps stopped, causing the Pit to begin filling with water. It also provides answers to common questions, including whether the Pit will ever overflow and whether earthquakes in the Butte area had any effect on the Berkeley Pit.

Inside every printed issue of PitWatch, and on this web site, is a graphic showing how the water is moving underground, plus current water-level measurements for key monitoring spots.

The committee welcomes and encourages questions and comments. The content of PitWatch is largely driven by community interest in specific topics. If you have questions about the Berkeley Pit or if you would like to order back issues of PitWatch, please contact us.

Send e-mail to info@pitwatch.org or send a letter to PitWatch, Berkeley Pit Public Education Committee, Butte-Silver Bow Planning Department, 155 W. Granite St., Butte, MT 59701.

BERKELEY PIT
PUBLIC EDUCATION COMMITTEE

The purpose of the Berkeley Pit Public Education Committee is to keep Butte residents and students informed about the Berkeley Pit and the surrounding underground mine-flooding areas.

Local residents make up more than half of this volunteer group, with other members drawn from entities directly involved with the Berkeley Pit Project.

The Committee's work is staffed by the County and funded by ARCO and Montana Resources as part of their responsibilities under the Record of Decision and Consent Decree.

CITIZEN MEMBERS:

	Brian Park (Chair)
	Roberta Forsell Stauffer (Vice-Chair)
	Joe Griffin
	Dave Isakson
	Carol Link
	Josh Peck
	Debbie Smith

OTHER MEMBERS:

	Mike Sheehy, Butte-Silver Bow Commissioner
	Tad Dale, Montana Resources
	Bernard Harrington, Walkerville Mayor
	Stacie Barry , Montana Tech Mine Waste Program
	Jill Larson, Citizens Technical Environmental Committee (CTEC)
	Daryl Reed, MDEQ
	Marci Sheehan, Atlantic Richfield Co.
	Sara Sparks, EPA

With assistance from the Clark Fork Watershed Education Program, www.cfwep.org.  

If you want more information about the Berkeley Pit and mine flooding issues, back issues of PITWATCH are available. Hard copies are available and all feature stories are also posted on the website.

ROD (1994) and CD (2002) available for review

If you want to read the official Record of Decision (ROD) for the Butte Mine Flooding Superfund site, or the Consent Decree (CD), review copies are available at the following locations:

MT Tech Library, 1300 W. Park

Butte EPA Office, County Courthouse, 155 W. Granite

25 years since pumps stopped
For more stories from the current issue of PitWatch, go here.
Over 25 years ago, back in 1982, economic factors led the Atlantic-Richfield Corporation, or ARCO, now a subsidiary of British Petroleum, to cease mining operations at the Berkeley Pit. Underground mining had come to an end six years earlier, and, after the neighboring East Berkeley Pit (now known as the Continental Pit) closed on July 1, 1983, the future of mining on the Butte hill was uncertain at best. Soon after, the Berkeley Pit was classified as a federal Superfund site by the United States Environmental Protection Agency (EPA). According to the EPA, a Superfund site is an uncontrolled or abandoned place where hazardous waste is located, possibly affecting local ecosystems or people.           

The end of mining at the Berkeley also marked the beginning of the Berkeley Pit lake we see today. Deep in the Kelley Mine at the 3,900-foot level, the pumps used to dewater the underground mines and the Berkeley Pit ran until April 23, 1982. Without pumping, the Berkeley began to fill with water flowing into the Pit from both surface runoff and groundwater. Due to both the natural geochemistry of the area and mining activities, the water is highly acidic and contains high concentrations of dissolved heavy metals.

But by 1985, ARCO had sold a portion of its holdings to Montana businessman Dennis Washington. Mining operations in the Continental Pit, as well as heap leaching of old Berkeley Pit leach pads, were resumed by his new company, Montana Resources.

In 1994, EPA and the Montana Department of Environmental Quality (DEQ) issued the Record of Decision (ROD) for the Butte Mine Flooding Operable Unit, which includes the Berkeley Pit. The ROD, according to the EPA, is a technical and legal document that: 1) summarizes the science behind the cleanup decision; 2) demonstrates how the remedy selection process was carried out; and 3) provides a thorough site history and includes public concerns, comments, and EPA responses.

In 1996, as directed in the ROD, water flows from Horseshoe Bend, a drainage to the north of the Berkeley Pit, were diverted away from the Berkeley and instead pumped up to the Yankee Doodle Tailings Pond that sits along the west slope of Rampart Mountain. At this facility, the ground-up rock (also known as tailings) that is generated as a byproduct of the milling process is deposited in order to settle out the solids and recycle decanted water back into the mill system. This diversion reduced the rate at which the Berkeley was filling with water, keeping up to 3,000 gallons per minute of surface water from flowing into the Berkeley.

In 1998, Montana Resources began pumping water out of the Berkeley Pit for copper recovery, a technique still used at the mine today. The copper-rich water is pumped over scrap iron, and, in a replacement reaction, the copper solidifies as sludge, while iron takes its place in the water, which returns to the Pit by gravity flow, thus not increasing or decreasing the total volume of Pit water.

The diversion of water from Horseshoe Bend was discontinued on June 30, 2000, when increased costs led Montana Resources’ Continental Pit mine to shut down. As a result of this shutdown, conditions contained in the 1994 ROD required Montana Resources and ARCO to begin design of a water treatment plant.

But, with copper prices rising, the mine again reopened in 2003, since which time it has continued to operate. Shortly after the Continental Pit reopened, the Horseshoe Bend Water Treatment Plant went online ahead of schedule on November 17, 2003, again diverting Horseshoe Bend flows and preventing this water from entering the Pit.

The Horseshoe Bend plant, which will eventually be used to pump and treat Pit water in order to keep it below the critical level, uses lime addition to reduce the acidity of the water and cause metals to precipitate out. In the long term, treated Horseshoe Bend water and, eventually, Berkeley Pit water will be used by the active mine as long as it is operating. If there is no active mining use for the treated water, it will then be pumped to the Metro Storm Drain just downstream of its confluence with Blacktail Creek near Montana Street, the official beginning of Silver Bow Creek.

When all is said and done, since the day the pumps in the Kelley turned off in 1982, water levels have risen over 3,100 feet in the East Camp system (which includes the Berkeley Pit, as well as the surrounding underground mine workings and bedrock aquifer), and over 230 feet in the separate West Camp system.

Current projections anticipate that pumping and treating of Berkeley Pit water will need to commence in 2021, although that date is dependent upon many factors: a reduction in waters flowing into the Berkeley would push the date further into the future, whereas an increase in water flows would necessitate an earlier date. The preliminary results from a performance test conducted in early 2008 indicate that the Horseshoe Bend Water Treatment Plant meets all discharge standards set by the EPA.

Over the active lifespan of the Berkeley, approximately 320 million tons of ore and over 700 million tons of waste rock were mined from the Pit. Put another way, “The Richest Hill on Earth” produced enough copper to pave a four-lane highway four inches thick from Butte to Salt Lake City and 30 miles beyond.