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Little McCormick Creek Mine Reclamation

Placer mine tailings
Little McCormick Creek is a tributary of Ninemile Creek, located approximately ten miles upstream from Ninemile Creek’s confluence with the Clark Fork River.  The watershed is 9,500 acres in size and is managed primarily by the Lolo National Forest.  Little McCormick Creek was intensively placer mined for gold during the last century.  More recently, a local miner conducted a large-scale operation on the Glory Hole claim from 1978 to 1997.  In October of 1997, the miner removed his equipment, abandoned his claim and left the US Forest Service with 250 feet of diverted stream channel, one mile of mining spoil piles and a 15-20 foot high undercut bank that spans approximately sixty feet.  The Forest Service could not initiate reclamation work, finding the miners’ $1,250 bond to be highly inadequate.

Historic mining and resource extraction has extensively altered the stream channel and altered stream flows on Little McCormick Creek. There is an estimated 503 tons of sediment entering Little McCormick Creek each year from unstable streambanks, and the base level of the valley bottom has been lowered a minimum of 12 feet.  While the stream is not confined by dredge piles, the channel lacks a functional floodplain, and there is little remaining riparian vegetation in the disturbed materials.  Because of these disturbances, Little McCormick Creek is listed on the Montana Department of Environmental Quality’s 303(d) list of impaired waterbodies.

Little McCormick, in contrast to mainstem Ninemile Creek, contains healthy populations of native westslope cutthroat, a species petitioned for listing under the Endangered Species Act.  Only westslope cutthroat have been surveyed in the upper portion of the stream, probably because of a dewatered section of stream and mining crib dam that acts as a fish barrier.  Placer mining, which involves the dredging of streambed cobbles, often results in a loss of surface water.   On Little McCormick Creek, a .25 mile section of stream goes dry during summer flows, which effectively bars westslope cutthroat from accessing 2.79 miles of high quality habitat upstream. The risk of extinction for westslope cutthroat populations in Little McCormick Creek is high based on the lack of a migratory component and the clustering of fish in close proximity, where a catastrophic event could affect the entire population.

Bedload sampling
The project team has collected pre project data on fish populations, macroinvertebrates, stream habitat, channel cross sections and long profiles and bedload transport.  In May of 2008, Montana Tech of the University of Montana spent one week on site preparing a geophysical investigation of Little McCormick Creek to determine bedrock depth and the nature of existing sediments within the drainage. Methods included seismic refraction and electrical resisitivity.

The design of the Little McCormick Creek project will focus on channel stability, bank erosion and stream dewatering. Implementation is scheduled for 2009-2010.