A Modern Approach to a Historic Problem
The Environmental Protection Agency listed the California Gulch site on its National Priorities List in 1983. It consists of about 18 square miles in Lake County including the city of Leadville, parts of the Leadville Historic Mining District and a section of the Arkansas River. Former mining operations contributed to metals contamination in surface water, groundwater, soil and sediment. Cleanup is complete at over 90 percent of the site. However, historic mine waste piles still remain. The Colorado Department of Public Health and Environment has also been active at the site.
Historically, mined material considered to contain low mineral content was removed to the surface and placed in piles as waste. These piles contain acid-bearing metals that travel into the Arkansas River. Breece Hill and Evans Gulch, located East and North of Leadville respectively, both within the Superfund site, are the first areas targeted for cleanup.
Former mining operations in the California Gulch contributed to metals contamination in surface water, groundwater, soil and sediment.
Waste generated during the mining and ore processing remain on the land surface.
CJK Milling plans to remove over 1 million tons of acid-generating mine waste in and around California Gulch. While considered uneconomic by miners at the time, the mine waste material still contains economically viable quantities of gold and silver. CJK’s cleanup plan removes historic mine waste from the environment, processes it to recover gold and silver at the mill, then places the processed tailings in a double-lined storage facility where it can no longer contaminate the environment. The minerals are beneficially reused, and the land is restored to pre-mining conditions.
The Colorado Department of Public Health and Environment supports this work and the remediation approach exceeds the EPA Record for Decision for the waste pile on Breece Hill.
Reprocessing mine waste captures gold and silver, secondary metals and other valuable industrial materials.
Mine reclamation is the process of restoring land that has been mined to a natural or economically usable state.