USGS Tar Creek, Oklahoma
Beginning in the late 1800's, zinc and lead were mined from resource-rich formations in northeastern Oklahoma. By the 1960s, the higher grade ores had been depleted and the mining companies had departed, leaving miles of abandoned tunnels and hundreds of piles of "chat," the gravel-like residue of the ore milling process, scattered in and around the Tar Creek communities in Ottawa County, Oklahoma, an area encompassing 360 square miles.
Over time, the abandoned mine tunnels flooded and rain water leached heavy metals from the chat piles. By the 1970s, acid charged water from the flooded mine tunnels and leachate from the chat piles had combined to pollute both ground and surface water. Tailings from the underground mines generated hundreds of toxic spoil piles on the surface that extended over the 84-square-mile mine area. The Environmental Protection Agency (EPA) classified the Tar Creek Mine Area as "one of the worst hazardous waste sites in the nation" when it added the site to the Superfund list in 1983.
In 2004, AeroMetric incorporated the use of DMC and LiDAR technologies to assist the State of Oklahoma, Department of Environmental Quality, Water Quality Division in determining the magnitude of effort involved in the removal of 1,022 chat piles. The aerial images collected by AeroMetric showed the surface ravages of abandoned lead and zinc mining on the Tar Creek EPA Superfund site in northeastern Oklahoma.
The analytical process utilized both DMC imagery and LiDAR elevation data. From the LiDAR data, a classified elevation map was prepared. This process aided in the separation of piles from depositional areas. The DTM aided in determining the area, slope, and erodability of the piles and the depositional areas. This analysis enabled reclamation planners to prioritize their response based on environmental and health and safety impacts of the chat pile features.
