The Copper Basin Mining Site, located in southeast Tennessee, was the site of extensive metals and copper mining and sulfuric acid production that dated back to the mid 1800s. Historic mining and related activities resulted in environmental degradation. Various government agencies and private parties have taken steps to revegetate the area and improvements in erosion control and habitat restoration are evident. However, the Copper Basin remained environmentally degraded from the presence of mining materials and mineral processing by-products, and continued releases of acidic, metal-laden water.

Accordingly, OXY USA, Inc. and its subsidiary Glenn Springs Holdings, Inc. (GSH), the US Environmental Protection Agency (USEPA), and the Tennessee Department of Environment and Conservation (TDEC) agreed to address these remaining environmental concerns, including reducing ecological risk to the Ocoee River. Part of this agreement was to develop and implement interim actions that would result in immediate progress in improving ecological conditions while a phased approach of long-term remedial actions was identified and implemented.

Interim remedial actions have been implemented and have resulted in substantial improvements to ecological conditions in the Copper Basin. These actions include diversion of clean water around contaminated water, treatment of acid and metal-laden tributaries, capping of mining wastes, remediation of PCB-contaminated soils, revegetation of mine-scarred lands, stream restoration, and construction of demonstration wetlands for passive treatment of acid mine drainage. These interim actions have resulted in a reduction of metals loading to the Ocoee River by more than 10,000 pounds per day, a 94% reduction.  

Essentially, three strategies led to these unprecedented results:

1) Performance-Based Goals. The state-EPA-private party collaboration resulted in performance-based goals that emphasized risk-based limits and biological integrity. In other words, the goals stressed practical solutions to achieve immediate benefits. Some of the performance-based actions included wetlands demonstrations, stream restorations, PCB removals, physical-hazard reduction measures such as fencing, and biosurveys to monitor progress towards biological integrity.

2) Innovative Solutions. Much of the progress to date has been due to unconventional engineering solutions. To treat the North Potato Creek watershed, a flooded open-pit mine, the South Mine Pit, was used as an integral part of a treatment system. Using the 200-foot-deep pit instead of building clarifiers resulted in a marked reduction in contaminant flow to the Ocoee and significant cost savings. Another effective solution was to dispose of non-hazardous materials on-site by placing them into the anoxic zone of an abandoned underground mine. Not having to transport the material off-site led to significant cost savings while still fully protecting the area streams.

3) Adaptive Management. An adaptive management approach made the most of the collaboration of private party, state and EPA by recognizing that it was in everyone’s best interest to improve the environmental conditions at the site. This acknowledgement allowed improvements to be made to the worst problems first, such as significantly reducing the loading of metals into the Ocoee River, without going through the normal process of investigation and development of final remedies. It also allowed monitoring the success of these interim actions in order to choose future actions based on which actions were successful and which actions were not successful. The primary interim actions were to provide water treatment in both watersheds to reduce the metals loading to the Ocoee River and to divert clean water to prevent mixing of clean water with degraded water.

Additional studies and remedial actions are underway. These will lead to continued progress in the Copper Basin. If this site had been handled as a traditional Superfund site, everything that has been accomplished in the past few years would still be waiting for the green light. The difference those few years have made is that 8.5 million pounds of metals have been removed by the water treatment systems since 2002 which would otherwise be in the Ocoee River. Instead, the Ocoee is running clearer than it has in over a century and aquatic life is flourishing.