U.S. Water News Online
RESTON, Va. -- Cleanup standards for more than half a
million abandoned mines
scattered throughout the nation need to take into account local geology as
well as results of human activities, according to a new report by the U.S.
Geological Survey (USGS). As a case in point, the study cites toxic
contamination from an open-pit gold mine at Summitville, Colo.
"The very names of creeks in the Summitville area -- Bitter Creek,
Creek, and Alum Creek -- suggest that the waters were naturally contaminated
by metals that raised the acidity long before the recent Summitville mine
opened," said Trude King, editor of the 38-page USGS report. "An important
part of the remediation efforts at the mine has been determining the natural
condition of the area," noted King. "Knowing the background levels of metals
gives us an appropriate goal for remediation that is cost-effective and
The USGS report "Environmental Considerations of Active and
Lands: Lessons from Summitville, Colorado" notes that scientists determined
that acidic contamination of water around the abandoned mine is the result of
both the area's geology and of human action. When the mine closed in 1992,
the state of Colorado asked the U.S. Environmental Protection Agency to take
over the site and stop the leakage of water contaminated with heavy metals
and cyanide from reaching the Wightman Fork of the Alamosa River. The total
cost of remediating the site has been estimated at $120 million.
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