Superfund Information Systems: Site Profile

Superfund Site:

NEWTON COUNTY MINE TAILINGS
GRANBY, MO

Cleanup Activities

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Background

The Newton County Mine Tailings site (Site) is located in the northern half of Newton County, Missouri, and is part of the Tri-State Mining District which encompasses approximately 2,500 square miles of Missouri, Kansas, and Oklahoma. Mining at the Site was conducted from around 1850 to 1970. After 150 years of mining activities, the presence of chat piles, tailing impoundments, and waste mine rock piles, are common features of the landscape in Newton County. Over the past few decades much of the total volume of surface mine waste has been removed and reused. However, there are still hundreds of acres of mining and milling wastes that remain. Much of the wastes are contaminated with residual heavy metals and have the potential to contaminate surface soils, groundwater, surface water, and stream sediments.

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What Has Been Done to Clean Up the Site?

 

 

The Site is a concern because of the mining and milling wastes remaining on the surface throughout the county. The wastes constitute a significant source of heavy metals contamination with potential for exposure to people and environmental receptors. Past mining and milling practices have also resulted in the contamination of surface soil, sediments, surface water, and groundwater in the shallow aquifer. The primary contaminants of concern are lead, cadmium, and zinc.

A preliminary assessment was conducted in the Granby area in 1986 revealing elevated levels of cadmium, lead and zinc significantly above background concentrations in soil and groundwater. In 1989, MDNR reconfirmed elevated lead levels in surface water and soil. An expanded site assessment was conducted by EPA in 1995 around Granby, Wentworth, and Stark City that focused on determining heavy metals concentrations in mining and milling wastes, surface soils, surface water, and stream sediments. The discovery of an elevated blood-lead level in a child living in the Spring City area in 1995 resulted in further assessment activities of residential yard soil and private drinking water wells in and around Spring City. As a result of these assessments, EPA expanded its investigations of private water wells and residential yard soil in known mining areas throughout the country.

Due to the large number of private residential drinking water wells identified with high levels of lead and cadmium throughout the Site, EPA began providing bottled water to homes in 1998. This action served as a temporary response action while public water supply systems were designed and constructed as part of the removal action to replace the contaminated wells. EPA completed construction of public water supplies that supply new public water supply mains to serve areas with contaminated residential wells. Additionally, approximately 100 individual deep-aquifer drinking water wells have been installed for homes where it was not feasible to install public water supply mains.

In 1999, EPA began a removal action for lead-contaminated residential yard soil in approximately 100 properties in the OU 02 portion of the Site. Meanwhile, the PRPs removed lead-contaminated residential yard soil at approximately 300 properties in the OU 01 portion of the Site, mostly in the city of Granby, under an Administrative Order on Consent. EPA placed the Newton County portion of the Tri-State Mining District on the National Priorities List (NPL) on September 29, 2003. Wastes in and around 14 mining camps located within approximately 300 square miles of Newton County have been grouped into five subdistricts: Spring City/Spurgeon, Diamond, Granby, Stark City, and Wentworth. EPA designated two operable units (OUs) for cleanup activities due to the location of mine and milling wastes and the location of mining operations by various potentially responsible parties (PRPs) who are liable for cleanup actions. OU 01 is the Diamond, Spring City, and Granby subdistricts, and contains the locations of mines and mills owned or operated by PRPs. OU 02 encompasses the remainder of Newton County where no viable PRPs have been identified.

The remaining risks to the environment and potential human exposure at the Site result from the presence of the mining and milling wastes located throughout the county. In 2009, EPA completed a Remedial Investigation/ Feasibility Study (RI/FS) which focused on these wastes and associated soils. A Record of Decision (ROD) was issued in June 2010. The major components of the selected remedy are:

  • Removal of metals contaminated mining and milling wastes, soils, and intermittent tributary stream sediments
  • Disposal of the contaminated wastes, soils, and sediments in a central repository to be constructed on site
  • Capping of the repository with an 18-inch soil cover
  • Recontouring the excavated areas to promote drainage
  • Revegetation of the excavated areas and the repository with native grasses
  • Monitoring Site streams for assessing the effect of cleanup
  • Establishing institutional controls to restrict the future use of the disposal areas

EPA Region 6 and 7, in conjunction with the USFWS, Native American Tribes, and state environmental agencies (Kansas, Missouri, and Oklahoma) are currently collecting and evaluating characterization and human health and ecological risk data throughout the reach of the Spring River basin in Missouri, Kansas, and Oklahoma as a coordinated watershed effort within the TSMD. All of the Site subdistricts drain to the Spring River basin. A remedy decision to address the remaining surface water at the Site has not been made.

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What Is the Current Site Status?

Removal of contaminated residential yard soils is complete. Replacement of residential water supplies is also complete. The long-term remedy includes removal and disposal of contaminated soils and sediments, capping of the disposal area, revegetation of excavated areas and the capped area, monitoring, and institutional controls to restrict the use of disposal areas. Cleanup activities are ongoing.

An interagency agreement (IA) was signed in November 2014 with the U.S. Army Corps of Engineers for the initiation of the first phase of remedial actions at the Site. The first contract for remedial action ended in October 2017 with the excavation of over 711,000 cubic yards of mine waste and contaminated soil and sediment. The next phase of construction is anticipated to complete the remediation of the Granby area. During the next contract, the EPA is continuing work on road repair and revegetation. Currently, the EPA is conducting sampling in areas of potential waste throughout the county. Nearly 1.5 million cubic yards of additional waste was identified through review of aerial photography and discussions with property owners. The culmination of this sampling effort and its impact to the selected remedy will be documented in an upcoming Explanation of Significant Differences document that will inclue a period for public comment.

 

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Sampling and Monitoring

Sampling in ongoing in newly identified areas of potential waste throughout the county. The next sampling event is planned for January 2018.

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Emergency Response and Removal

Cleanup has also included removal actions, or short-term cleanups, to address immediate threats to human health and the environment. Removal actions from 1999 to 2003 included excavation of contaminated soils from about 300 residential properties. EPA provided bottled water to affected residences until these homes are connected to public water supplies. EPA has also installed about 100 deep water wells (replacements) in isolated areas where water lines are inaccessible.

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