Southeast Missouri Lead Mining District (SEMOLMD)

State TrusteeFederal TrusteeAO Bureau

Also Known As

Incident Type




Case Status



Mining megasite covering multiple counties in the Southeast Missouri Ozarks.


Contaminants of Concern Include

Affected DOI Resources Include

Migratory Birds, Threatened and Endangered Species

Case Description

Missouri has a long and extensive history of lead (Pb), Zinc (Zn), and other metals mining. Since the 1720’s, over 6,000 individual explorations or mines have been registered within 51 of the 115 Missouri counties, with known production occurring in 39 counties. The Southeast Missouri Lead Mining District (SEMOLMD) is a combination of the “Old Lead Belt” and the Viburnum Trend. The Old Lead Belt is generally considered to comprise parts of seven counties including Crawford, Franklin, Iron, Jefferson, Madison, St. Francois, Ste. Genevieve, and Washington counties. The Viburnum Trend or New Lead Belt was identified in 1955 and ore production was initiated by the early 1960’s. The Viburnum Trend comprises parts of six Missouri counties including Crawford, Dent, Iron, Reynolds, Shannon and Washington counties and production of Pb, Zn, copper and silver continues there today. According to the U.S. Geological Survey (USGS) the Viburnum Trend and Old Lead Belt ranked #1 and #2, respectively for lead production within the United States and the Viburnum Trend ranked #10 for zinc production.

Mining and milling in Missouri in the early days consisted of hand dug surface pits. The ore was separated from the host or waste rock by hand-sorting and passing through course screens or jigs (sometimes called grizzlies). Lead was generally smelted on-site or close to the mine using crude hearths that burned wood. Mining techniques became more sophisticated with the introduction of the diamond-tipped drill in the 1860s, and mines generally became deeper and larger. Ore was separated from the host or waste rock by larger-scale milling techniques. Hearths were replaced by coal burning furnaces and eventually modern-day smelters. Milling consisted of separating coarse material from the ore with screens and jigs, which produced chat, and then through a gravity-separation aqueous process, which produced finer grained tailings. Tailings were typically deposited in an impoundment formed behind coarser grained chat, which served as a dam or berm. The mill wastes (chat and tailings) were often deposited on the ground near the mines with little control or regard to erosion. Indeed, mine wastes were known to be flushed down stream as a means of disposal. Most of the modern mining production in St. Francois and Madison Counties and the Viburnum Trend was from deep underground mines.

At this time, SEMOLMD contains three NPL sites: the Big River Mine Tailings Site (aka St. Francois County Mine Site or SFCMS), the Southwest Jefferson County Mining Site, and the Madison County Mine Site (MCMS). The Big River and Madison County sites contain several mine and mill sites across the counties with large mill tailings impoundments and chat piles covering thousands of acres of land. Both sites also have streams that contain many miles of heavy-metal contaminated sediment, including the Big River for the St. Francois County and Jefferson County site and the Little St. Francois River for the Madison County site. The trustees estimate that the Big River has over 90 miles of contaminated sediment from the St.Francois, Jefferson and Washington County sites. The Madison County Mine Tailings site contributes contaminated sediment to the Little St. Francois River.

Supporting habitats and food chains for federally listed species and migratory birds are contaminated with concentrations of hazardous substances that exceed exposure thresholds known to cause adverse effects. In total, it is estimated that releases from these mining sites have contaminated over 100 miles of stream sediment with Pb, Cd, Ba, Ni, Cu, and/or Zn. Over 3,500 acres of land are contaminated or covered with mine/mill waste in St. Francois and Madison Counties. It is estimated that 25,000 acres in the Viburnum Trend are contaminated by hazardous substances. The trustees are assessing impacts to natural resources, including the federally endangered pink mucket, scaleshell, spectaclecase, and sheepnose mussels, and migratory birds due to contaminated habitat and possible direct toxicity. 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).

National Chat Pile located in a town once known as Flat River, MO 1953, Credit: Chat Dumps of St. Francois county, McHenry

Southeast Missouri Lead Mining District, Credit: USFWS

Case Documents

 Document TypeDocument NameDocument Date


 MOA/MOU SEMOLMD additional MOU 11/04/2009
 MOA/MOU SEMOLMD Signed MOU 09/24/2004


 Study Report (Big River) Benthic Fish Densities 02/03/2010
 Study Report (Big River) Crayfish Metals Study 02/10/2010
 Study Report Big River Borrow Pit Monitoring Project 05/24/2012
 Study Report Floristic Quality Assessment 01/01/2009
 Study Report Freshwater Mussel Population 12/01/2009
 Study Report Mining Sediment in Channel and Floodplain Deposits 06/18/2010
 Assessment Plan Phase I Damage Assessment Plan 02/10/2009
 Study Report Sediment Toxicity Big River 11/03/2009
 NOI SEMOLMD NOI for BRMT and VTLMS 06/30/2008
 NOI SEMOLMD NOI for VTLMS 03/12/2009
 PAS SEMOLMD PAS for Viburnum Trend 2- signed 03/12/2009
 Study Report Songbirds Adverse Affects of Soil Lead 07/28/2014


 Settlement Agreement Consent Decree (ASARCO) 02/26/2008
 Consent Decree Consent Decree (Cyprus Amax and Missouri Lead) 11/05/2014
 Consent Decree Order Entering Consent Decree 12/29/2014


 Restoration Plan Restoration Plan Amendment 04/01/2019
 Restoration Plan and Environmental Assessment Restoration Plan and Environmental Assessment 06/01/2014

Map View

Case Contact

Columbia Ecological Services Field Office

Columbia, MO | (573) 234-2132 |

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