MINE SHAFT CLOSURE AT THE TAR CREEK SUPERFUND SITE

The Picher Mining Field of northeastern Oklahoma was the location of extensive lead-zinc mining from 1904 to 1970. Oklahoma led the nation in zinc production almost every year from 1918 to 1945. Approximately 187,000,000 tons of crude ore were mined from the Picher Field. More than 1.3 million tons of lead and 5.2 million tons of zinc were produced since mining began in 1891 near the small community of Peoria. Lead and zinc production from the Picher Mining Field ended in late 1970. Although small amounts of lead and zinc concentrates were produced until 1977, the large mines and concentrating mills were abandoned in 1970. Mine waste accumulations and acid mine drainage from the now-abandoned lead-zinc mines have become an environmental issue that has been the focus of environmental restoration activities since 1979. The area was designated by the Environmental Protection Agency (EPA) as the Tar Creek Superfund Site in 1983. The decades of mining have left the landscape dotted with over 1,200 abandoned mine shafts. These shafts are either open to the mine workings below or in varying stages of collapse. The Tulsa District Corps of Engineers is in the process of plugging the shafts that pose the greatest threat to the public by utilizing shaft location and condition data obtained from the Oklahoma Geological Survey (OGS). The OGS has been working in the Picher Mining Field since 1982 gathering mine maps, borehole data, and mine shaft location and condition information.

Public safety implications of mine shafts and mining related subsidence have been a concern of residents in the Tar Creek Superfund Site for many years. Shaft related and non-shaft related subsidence events have occurred in the Picher Mining Field since the beginning of mining operations and continue to occur. The Tulsa District Corps of Engineers is actively addressing public safety issues associated with extensive historical mining through an aggressive mine shaft plugging program.