The Camden County mining area was mined from 1830 to 1910, with lead as the principal product. After 1910, most of the mining was for barite, with galena (lead) as a minor by-product. By 1947, lead production in the Central Mining District (CMD) had totaled 24,855 short tons. Since 1950, no lead and very little barite have been mined. Mining operations and associated lands in the CMD area have been owned, operated, and managed by various entities and/or private citizens (USGS and Missouri Division of Geological Survey and Water Resources 1967). Hazardous substances typically associated with historic mining sites in Missouri include arsenic, barium, lead, and cadmium. The mining waste products often end up on driveways, in yards, and in children’s play areas.
The CMD–Camden County covers approximately 418 square miles in central Missouri. The climate of the area is characterized by cool winters and hot summers. The average total annual precipitation is about 38–42 inches. Camden County site soils range widely in texture, natural drainage, depth to bedrock, and other characteristics. The predominant soil types are deep to moderately deep, sloping to very steep, very cherty silt that forms on uplands. Contamination from historic mining activities potentially impacts 37,050 residents of Camden County.
The action memorandum for Camden County was signed on September 22, 2008. The response action included continued sampling of drinking water sources, excavating contaminated soils in yards, and providing alternative drinking water sources to properties which exceed the RAL for this site.
Site assessment activities were conducted from 2006 through 2014. Properties were sampled based on the Geological Survey and Resource Assessment Division's (GSRAD) Inventory of Mines, Operations, and Prospects database which identified more than 900 mining locations in the five-county Central Mining District area. The locations were mapped out, and then door to door sampling began. Field screening for lead contamination in surface soils occurred at 715 properties using an XRF spectrometer, and water was collected from 1,677 private drinking water wells.
The project was completed as of December 25, 2014 with a lag time for billing issues to be resolved. A total of 20 residential properties underwent a removal for contaminated soils and an additional eight residential properties were provided an alternative source of safe drinking water as a result of this removal action.
