Research continues on Pit Water

The unique environment of the Berkeley Pit and the surrounding Butte area has created numerous avenues for scientific exploration, both by local scientists and by researchers around the globe.

The research potential of the site is tremendous, and may represent a real renaissance for a geographic area characterized by years of mining, milling, and smelting waste. Research efforts have been undertaken locally at Montana Tech, the Montana Bureau of Mines and Geology, and MSE, and research groups from around the world have studied Pit water.

On a more local level, a cursory scan of Montana Tech Library resources turns up 23 thesis publications devoted specifically to researching aspects of the Berkeley Pit, as well as many more Pit-related research publications. And the research covers a diverse array of topics, including environmental engineering, geology, communications, metallurgy, chemistry, and physics.

A 1994 thesis by David Klemp, a graduate student in the Montana Tech Environmental Engineering program, investigated fog from Berkeley Pit water, a site familiar to most Butte residents. A 1996 thesis by Neil Massart, also from the Environmental Engineering program, offered an economic analysis of a crystallization process that was part of a broader evaluation of the potential for innovative technologies to remediate the Pit.

A large volume of additional research has focused on the study of various methods for bioremediating Pit water or the use of different technologies to treat Pit water. Other studies, like that carried out by Montana Tech Chemistry and Geochemistry graduate student Licette Hammer in 1999 and a similar study done by graduate student Margery Willett in 2001, focus on the amount and types of organic carbon present in the Pit, and the relationship between organic carbon and the larger Pit ecosystem.

In addition to the regular staff of scientists and undergraduate assistants at Montana Tech, the Stierles, at center, have also worked with local high school and middle school students over the years on science fair projects focused on Berkeley Pit microbes. The realization that a compound that could help cure cancer could be lurking in the Berkeley Pit is thrilling. They like to think that their microbes could be some of the richest "ore" ever mined from the Richest hill on Earth. Photo courtesy of Lisa Kunkel, The Montana Standard.

In addition to the regular staff of scientists and undergraduate assistants at Montana Tech, the Stierles, at center, have also worked with local high school and middle school students over the years on science fair projects focused on Berkeley Pit microbes. The realization that a compound that could help cure cancer could be lurking in the Berkeley Pit is thrilling. They like to think that their microbes could be some of the richest “ore” ever mined from the Richest hill on Earth. Photo courtesy of Lisa Kunkel, The Montana Standard.

Local scientists Drs Andrea and Don Stierle, both faculty members in the Department of Chemistry and Geochemistry at Montana Tech, recently garnered national publicity for their research, ongoing since 1996, on microbes living in the Berkeley Pit Lake. The unique nature of the Pit environment creates habitat for unusual microbes, sometimes called “extremophiles”, which could in turn produce novel chemistry with potential medical uses. The organisms themselves may also be effective bioremediators of the wastewater in which they grow.

The Stierles, aided by undergraduate research assistants at Montana Tech and local high school students and collaborating with scientists at Montana State University and the University of Montana, are “mining” these Pit microbes. They have already isolated several exciting new compounds, including a migraine preventative and several compounds with promising anticancer potential. They have also found an intriguing fungus that appears to pull metals from the Pit water itself.

The research process is complex. Microbes must first be isolated from water and sediment samples and established in pure cultures. A variety of carbon and nitrogen sources are used to determine which growth conditions yield the most active natural products. Extracted microbial cultures are tested to determine if they have potential as antibacterial, antifungal, anticancer, or immune system modulating agents.

The Stierles have been awarded almost $3 million in federal funding from the National Institutes of Health and the US Geological Survey to support their ongoing efforts at drug discovery from an acid mine waste lake.

Other scientists have experimented with the potential of algae to clean or bioremediate the Berkeley Pit. For most of the past decade, Dr. Grant Mitman, a Montana Tech biology professor, has been studying the ability of algae to remove heavy metal contaminants from Pit water. Through various metabolic, physiological, and biochemical processes, algae have the potential to reduce soluble metal ions in acid mine waters.

Limnocorrals, experimental enclosures which physically isolate a known volume of water and allow for the testing of various experimental manipulations at a relatively low cost, deployed in the Berkeley Pit. Photo by Nicholas Tucci.

Limnocorrals, experimental enclosures which physically isolate a known volume of water and allow for the testing of various experimental manipulations at a relatively low cost, deployed in the Berkeley Pit.

Dr. Mitman, along with graduate student Nicholas Tucci, applied this potential bioremediation solution in the Berkeley Pit in 2006. Algae occur naturally in the Pit, but lack nitrate, a common nutrient found in most fertilizers that is essential for algal growth. If nitrate is added to Pit water, the naturally occurring algae can potentially reach a concentration of millions of cells per milliliter, a virtual green soup of suspended organisms that have an ability to permanently remove dissolved metals from the pit. These organisms have been used to remediate other pit lakes around the world, and may one day lead to the natural restoration of the Berkeley Pit.

In the spring of 2004, Mitman and Tucci deployed nine acid- and metal-resistant cylindrical limnocorrals along the eastern edge of the Berkley Pit Lake. Limnocorrals are experimental enclosures which physically isolate a known volume of water, and allow for the testing of various experimental manipulations at a relatively low cost.

In this case, 500 gallons of pit water were used to fill the limnocorrals, and varying concentrations of nitrate were added as the experimental variable.

To determine if algal growth had an effect on Berkeley Pit water, water quality and algal populations in nutrified limnocorrals were continually monitored and compared with those in non-nutrified limnocorrals.

After the first year of data collection, concentrations of algae in the nutrified limnocorrals had increased from undetectable levels to two million cells per milliliter, and, as a result of this algal growth, both iron and arsenic concentrations in Pit water were significantly reduced. No significant changes in water quality or algal growth were detected in the non-nutrified limnocorrals.
Researchers are planning longer-term experiments testing the ability of algae to clean Berkeley Pit water. Algae, like other biological organisms, need time to achieve a substantial and healthy population. Long term experiments will be necessary to fully determine the potential for bioremediation in the Berkeley Pit.

While substantial research has been done on the Pit, there is clearly still a lot to learn. That is an exciting prospect for the Butte community, and in the future what we can learn from the Pit could represent the greatest treasure of the Richest Hill on Earth.

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