The Jumbo Mine Site is located in the White River National Forest in central Colorado, approximately 8 miles east of Keystone just on the west side of the Continental Divide. The Site is approximately 200 yards above Peru Creek on a mountainside surrounded by evergreen trees. The Site is located on private land and consists of a relatively small set of mine works. There is a single adit with a collapsed portal that produces acid mine drainage. Adit water flow fluctuates during the year as the seasons change and may vary from 30 to over 100 gallons per minute. The mine drainage currently flows directly on top of a mine waste rock piles that are approximately 25,000 cubic yards in volume. There is a cabin atop the waste rock pile. The Peru Creek/Snake River confluence is about two miles downstream of the mine. The Snake River flows into the Dillon Reservoir approximately 10 miles downstream and is a major municipal drinking water source of the Denver metropolitan area.
The Jumbo Mine operated from 1915 to 1918 and produced 6,727.99mt of ore (USGS MROL). The mine produced gold, copper, lead, silver, and zinc. The Site was identified in the early 1990’s Abandoned Mine Lands Inventory report and again mentioned in the Munroe report in 1999. The Colorado Department of Public Health & Environment, Water Quality Control Division Snake River Watershed Plan (Plan) states that the Site provides a significant metal-contaminated point source which flows into Peru Creek then the Snake River. The Snake River is the primary eastern tributary to the Blue River in Summit County Colorado.
Peru Creek, the Snake River, and several of its other tributaries are on the Colorado 303(d) listing as streams that do not meet water-quality stream standards due to low pH and high concentration of four trace metals: dissolved cadmium, copper, lead and zinc. Much has been done to study the problems in the watershed, beginning at least in the early 1970s. Most of this work has focused in the tributary Peru Creek, which is home to the largest, longest serving mine in the watershed, the Pennsylvania Mine. The Pennsylvania Mine has been addressed by the EPA and we are now looking to address the Jumbo Mine Site which was identified in the Plan as a “Priority One” potential remediation-project site that is significantly degrading the water-quality in the watershed.