Chevron Questa Mine site (formerly Molycorp, Inc.)
Superfund Redevelopment in Region 6
The Chevron Questa Mine site (formerly known as the Molycorp, Inc. site) in northeastern New Mexico includes an operational, underground mine, mill and tailing disposal facility. Ten large piles of acid-generating waste rock and more than 100 million tons of tailings have contaminated the soil, ground water and surface water, mainly with metals. The Red River, which flows past the site and is home to a cold-water state fish hatchery, has also become contaminated. As a result, the Chevron Questa Mine site was added to the Superfund National Priorities List for federal cleanup in September 2011.
On March 7, 2012, EPA and Chevron Mining Inc. (CMI) reached an agreement for CMI to perform removal actions at the site. These include:
- removing PCB-contaminated soil at the mill area, with off-site treatment/disposal (completed October 2012);
- removing historic tailing spill deposits along the Red River riparian corridor (work began February 2013);
- removing contaminated sediment at Eagle Rock Lake (work is planned to begin in late spring of 2014);
- installing a storm-water control structure for the lake inlet (completed December 2012); and
- lining the eastern diversion channel with piping to prevent the water from coming into contact with tailing material and contaminating the underlying ground water (work is planned to begin in fall 2013).
On September 25, 2012, another agreement with EPA set forth early design actions that CMI will conduct at the site. The early design work involves additional ground water investigation at the tailing facility, design support investigations for ground water extraction wells and expanded seepage collection systems, characterization of Spring Gulch waste pile borrow material, a waste rock pile pilot project, a slope stability analysis for the waste rock piles and treatability studies for water treatment.
Work plans for the additional ground water investigation at the tailing facility, investigations for ground water extraction wells and expanded seepage collection systems, characterization of Spring Gulch waste pile borrow material, and treatability studies for water treatment have been submitted to EPA for review and comment.