The Big River Site is made of two Superfund Sites located along the Big River, the Big River Mine Tailings Site (BRMT) in St. Francois County and the Southwest Jefferson County Mine site. The sites are located within the Old Lead Belt Mining District of Southeast Missouri which occurs on the eastern edge of the Ozark Uplift in Missouri. Until the 1860's, mining in the Old Lead Belt was restricted to shallow workings and pits. The early primitive mining resulted in small quantities of comparatively highly contaminated mine wastes. In 1864, the St. Joseph Lead Company bought 964 acres and initiated mining in Bonne Terre, Missouri. The introduction of the diamond-bit core drill in 1869 led to the discovery of numerous Pb-rich ore deposits under what became the towns of Bonne Terre, Desloge, Flat River, Leadwood, and Elvins. As many as fifteen companies were engaged in mining these deposits in the late 1800's and early 1900's. By 1933, the St. Joseph Lead Company had acquired all of the properties in the area, including the Federal Mine and Mill. The St. Joe Lead Company, whose direct descendant is The Doe Run Company, operated the Bonne Terre mine from 1864 to 1961, the Desloge Mine from 1929 to 1958, the Federal Mine from 1923 to 1972, and the Leadwood Mine from 1915 to 1962. Mining activities commenced near the Rivermines site in 1890 and ceased in 1940. The National (Flat River) Mine operated continuously from 1898 to 1933. Mining activities in the Old Lead Belt of St. Francois County decreased through the 1950's and 1960's as ore bodies were depleted and higher grade ores were discovered in the Viburnum Trend of Crawford, Iron, and Reynolds Counties. The Federal Mine and Mill were the last to close in St. Francois County in 1972. The U.S. Environmental Protection Agency (US EPA) listed the BRMT Superfund Site on the National Priorities List (NPL) in 1992.
There exist over 2,800 acres of chat, tailings, vegetated chat and transition zone soils contaminated primarily with Pb in and around the six (6) major piles of the BRMT site. Over 16,000 acres of contaminated floodplain and 90 miles of contaminated sediment have resulted from the releases of hazardous substances at and from the site. The contamination extends from St. Francois County downstream through the SW Jefferson County site to the confluence of the Meramec River. Although there was some mining in Jefferson County, the NRDAR case only focuses on contamination in and along the Big River caused by upstream inputs.
The Trustees are assessing injury to a wide array of species from exposure to heavy metals, including freshwater mussels, crayfish, riffle-dwelling fish, native plants, and songbirds. The FWS has particular concern over endangered freshwater mussels. The Meramec River (below the Big River) supports some of the largest remaining populations of the federally endangered pink mucket, (Lampsilis orbiculata), scaleshell (Leptodea leptodon), sheepnose (Plethobasus cyphyus), and spectaclecase (Cumberlandia monodonta).
The Trustees are engaged in an extensive level of coordination with other state and federal agencies in an effort to clean-up and restore the Big River. Agencies involved in this effort in addition to the Trustees (FWS and MDNR) include U.S. EPA, U.S. Corps of Engineers, Missouri Department of Conservation, Missouri Department of Health and Senior Services, and the Agency for Toxic Substances and Disease Registry. Activities from other agencies of special interest to the Trustees and the NRDAR case are EPA's Feasibility Studies, Proposed Plan, and Record of Decision for clean-up of the river and surrounding lands, and the Corps' Meramec Feasibility Study, which provides a partial design for restoration on the river. Restoration projects described in the Corps's study include bank stabilization, sediment traps, and re-forestation of riparian corridors.