Isabella/Eureka Mining and Processing Area

Operations in the Isabella/Eureka area included mining of the the nearby ore body, smelting and roasting of ores, acid production by the chamber and contact methods, and metals concentration by flotation. These operations began in the 1850s and continued with only short interruptions until the mid 1970s. Investigations of the surface materials (largely mining and processing wastes) and the nearby streams have identified sources of continuing contamination to North Potato Creek.

The Lead Chamber Acid Plant, which operated from 1909 until 1941, was disassembled in 1942. Some of the more than 1270 metric tons (1,400 tons) of lead from the plant remains as contaminants in the soil over several acres of the former site. In 2003, GSHI constructed an impermeable cap over more than three acres of the site to isolate contaminated soils form human contact and exposure to the environment. GSHI has also begun remediation of the Isabella process areas to remove human health and ecological risks posed by the waste materials along Ellis Branch and North Potato Creek.

Analysis for PCBs has included in most sampling within the project. PCB contamination at action levels is limited to a small area near the Isabella Mine which has been remediated. All known PCB/PCB contaminated equipment was removed, recycled or properly disposed.

The Isabella Pit, located between the Isabella and Eureka shafts, was formed by a series of collapses beginning in 1960 and continuing to 1972. The irregularly shaped pit measures approximately 300 meters (1000 feet) long by 100 meters (300 feet) wide and extends to a depth of about 85 meters (280 feet) below the water surface. The water in the pit is highly contaminated and is pumped to the London Mill Treatment Plant for removal of metals and acidity.

As part of the remediation plan for the entire site, GSHI is studying the use of the pit as a sub aqueous disposal site for as much as 380,000 cubic meters (500,000 cubic yards) of mining and processing wastes. Disposal under water would provide a chemically stable disposal site where continued production of acid and metals from the wastes would be prevented. it has been shown that the method is at least as protective as a lined landfill and the pit does not leak into North Potato Creek. GSHI is awaiting approval of the disposal plan by TDEC. A conveyor system has been erected to deposit the material into the pit.

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