2010-08-11_ENFORCEMENT - M1977300

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30. The Operator introduced several examples of flooding mines as a remediation strategy. However, the Division rebutted these examples with additional data showing that water treatment at the various flooded mines was still necessary. The Operator cites the Lokken Mine in Norway saying that "water quality improved considerably when the mine was flooded after partial closure." (June 25, 2010 Rationale for Not Conducting Mine Dewatering and Mine Water Treatment at the Schwartzwalder Mine, by Susan Wyman, p. 7, citing a 1997 article.) However, the Division cites more recent information noting that by 2009 the situation at the Lokken Mine had deteriorated. "A plan of action dating from 1992 has become obsolete and new initiatives are needed immediately to save a river." (Division's power point presentation, citing the Norwegian Institute for Water Research, 2009). 31. The Operator also testified that dewatering the mine poses substantial challenges because the mine is no longer operable, access is difficult, and drilling to access the mine pool poses significant challenges. However, the Division proposed alternative methods and equipment including lowering a pump inside a casing string and using centralizers to minimize hanging inside the casing. The Division also proposed exploring the possibility of placing the pump in shaft no. 2, which bottoms at 800 feet below the Steve Level. In addition, the Division supplied many examples of successful drilling to intercept small targets. Drilling can be accomplished when encountering void space. And finally, the Operator can refurbish and repair the mine, including installing ventilation, to make the mine safe to enter. 32. At the hearing the Division described the mine pool as "a 144 million gallon tank of water containing 42,000 lbs. of uranium, perched 500 feet above and less than two miles from Ralston Reservoir." Also, Denver Water and Arvada Water are currently bearing the costs of treating the water contaminated by Cotter. The Division considers the costs of the corrective actions less than the costs of cleaning the water in Ralston Creek and Reservoir. 33. Ralston Creek flows into Ralston Reservoir. Ralston Reservoir provides drinking water to Denver and Arvada. The Operator is responsible for the increased uranium in Ralston Creek through the alluvial fill and mine pool. The mine pool is contributing to the contamination of Ralston Creek and Reservoir. The mine pool is affecting the hydrologic balance of the affected land and surrounding area. The mine pool could significantly negatively impact water quality in Ralston Creek and Reservoir. Dewatering the mine pool to a level below the level of Ralston Reservoir will ensure that the hydraulic gradient is again reversed away from Ralston Creek and Reservoir - by recreating a cone of depression. Protecting the water in Ralston Creek and Reservoir is essential. Dewatering the mine will be expensive. However, the benefit (protecting Denver and Arvada's drinking water supply) justifies the expense. Cotter Corp. Schwartzwalder Mine 6 M-1977-300 MV-2010-018