Copper Basin Mining DistrictCopperhill, Tennessee
The Copper Basin Mining District site is located in southeast Polk County between Ducktown and Copperhill, Tennessee. The site includes parts of the North Potato Creek and Davis Mill watersheds, and a 26-mile stretch of the Ocoee River that was affected by historic mining activities at the site. Mining, processing, chemical manufacturing, and waste disposal at the site began in the late 1800s. Mining ended in 1987 and chemical production ended in 2000. The historic mining and processing at the site caused erosion and the transportation of tens of millions of cubic yards of soil and waste to the Ocoee River and also left the land totally barren. Since the late 1990s, the United States Environmental Protection Agency (EPA) and the Tennessee Department of Environment and Conservation has provided oversight of cleanup and restoration of the Copper Basin Mining District site.
Copperhill Industries Background, Davis Mill Watershed:
In 2010, Copperhill Industries, LLC began recycling iron rich material from remnants of the historic mining work left behind in the Davis Mill watershed. The recycled material is shipped off-site and used in a variety of industries. Since 2010, Copperhill Industries has removed 1.8 million tons of metals from the Davis Mill watershed.
Revegetation at Copperhill Industries, Davis Mill Watershed:
After recycling is complete in an area, Copperhill Industries restores and revegetates the land. The first restoration project began in 2016 following the completion of waste removal and recycling in a 25-acre portion of the watershed. Land reclamation and vegetation establishment were challenging because of the low soil pH and lack of organic matter. After several failed attempts with the traditional reclamation approach of adding soil, lime, and fertilizer, the EPA suggested using biosolids. Biosolids had been used successfully at other historic mining sites in the county. Biosolids started being used on the site in December 2018 and they provided a much-needed source of nutrients and organic material for the mine-scarred land.
What are Biosolids?
Biosolids are nutrient-rich organic products resulting from the treatment of wastewater. Currently, exceptional quality (EQ) biosolids are being produced and used in the Davis Mill watershed. Previously, Class B biosolids from Moccasin Bend Wastewater Treatment Plant were used. These products are no longer used by Copperhill Industries. The current project uses equipment to process non-hazardous municipal wastewater residuals with quicklime to produce EQ biosolids. Quicklime rapidly reacts with water in the wastewater treatment residuals, producing heat and elevated pH sufficient to kill all biological action, eliminating odor and vectors. The source of the municipal wastewater residuals is wastewater treatment facilities in Cobb County, Georgia. The biosolids are only being land applied within the Davis Mill watershed. Due to the landscape position and hydrology onsite, these materials are fully contained within the watershed.
Best Management Practices
EPA and TDEC have worked with the site owner and operator to reduce odor concerns. The first step to reducing odor was to stop using class B biosolids and only use EQ biosolids. TDEC recognizes wastewater residuals do generate odors in trucks when they are transported from Georgia. Care is taken to reduce vehicle odors where possible. This includes transporting the biosolids in sealed, watertight trucks with heavy-duty tarps and pressure washing trucks after being unloaded. Processing of biosolids is done under a covered area. Tracking or spilling of these materials onto roadways is prohibited.
TDEC and EPA staff have been to the site several times and have not observed any violations or polluting conditions. Any evidence, such as photographs, of leaking trucks should be sent to the contacts listed above.
Under Tennessee under Tenn. Code Ann. 0400-40-15, state rules establish standards for the land application of biosolids including general requirements, contaminant limits, management practices, and operational standards. Treatment processes for EQ biosolids eliminate pathogens, including viruses. EQ biosolids are exempt from all requirements of these rules if they meet certain criteria, other than the requirement that the facility that prepares EQ biosolids document in its annual report the information contained in subparagraph (7)(a) of Rule 0400-40-15-.02. The TDEC Division of Water Resources has determined the biosolids being used by Copperhill Industries meet EQ standards.
The Ocoee River is listed on TDEC’s Year 2022 303(d) List as impaired by copper, iron, flow regime modification, sedimentation, zinc, siltation from mine tailings and contaminated sediment impacts from abandoned mining. These impacts to the Ocoee River were from historic operations at the Copper Basin Mining District site. The source of the copper, iron, zinc, and siltation have been addressed through a series of remedial actions and continues to be addressed through the treatment of water from the Davis Mill watershed prior to discharging to the Ocoee River. Routine monitoring of the Ocoee River indicates that there are no current water quality issues from the Copper Basin Mining District impacting recreation on the Ocoee River. The biosolids activities occurring in the Davis Mill watershed are not impacting water quality in the Ocoee River. More water quality assessment information can be accessed on the Division of Water Resources data viewers.