SUMMITVILLE Mine

When cyanide-contaminated heap leach pad water from an abandoned gold mine threatened catastrophic release into local streams in the Rocky Mountains, the team performed emergency response remediation in mid-winter sub-Arctic conditions. The scope of work included the excavation, transportation, and consolidation of more than 1 million tons of waste rock at the Cropsy Waste Dump, a remote mine site at an elevation of 11,500 feet; construction of support facilities and mobilization of heavy equipment; and improvement and maintenance of access and haul roads, including snow removal. The team constructed drainage diversions and dams; excavated, transported, and placed 1.65 million cubic yards of soil and mine waste material; and constructed a clay cap on top of placed material. Overall, the team treated more than 2.2 billion gallons of acid mine drainage leachate and heavy metals.