Cimarron Mining Corp.

Overview

The Cimarron Mining Corp. site sits in Carrizozo, New Mexico, and covers two former mill areas where iron and precious metals were extracted from ore between 1960 and 1982. Cyanide was used at the Cimarron Mill starting in 1979. Milling operations left behind contamination in soil, sediment, and groundwater at both locations. The site was added to the EPA's National Priorities List (NPL) in October 1989 and divided into two operable units: the Cimarron Mine Site and the Sierra Blanca area.

Contaminants at the Cimarron Mine Site include chloride, chromium, cyanide, fluoride, iron, lead, manganese, nitrate, selenium, sulfate, and total dissolved solids in groundwater. At the Sierra Blanca area, arsenic, barium, lead, and manganese appear in groundwater, soil, sludge, solid waste, and debris. EPA identified these substances as posing unacceptable risks to human health or the environment.

Cleanup happened in two main phases. At the Cimarron Mine Site, a groundwater extraction system ran from 1993 to 2001, and contaminated soil was excavated and disposed of on-site. At Sierra Blanca, contaminated soil and waste rock were excavated, stabilized with cement, placed in on-site repositories, capped, and revegetated by 1997. EPA removal actions began as early as August 1987. The New Mexico Environment Department (NMED) took over operation and maintenance in 2005 and conducts periodic groundwater monitoring around the repositories every four to five years.

Human exposure across the entire site is currently under control, and groundwater migration is also under control with no unacceptable discharge to surface water. Drinking water for about 1,500 nearby residents is protected through 29 municipal wells. Restrictive covenants recorded in 2006 limit ground drilling near both repositories. The site achieved Sitewide Ready for Anticipated Use status on September 20, 2007. A partial NPL deletion covering surface and subsurface soil, sediment, and waste rock was published in August 2000, and the final deletion for groundwater in Operable Unit 1 followed on September 30, 2020. The Cimarron Mill area now hosts an auto repair and salvage yard, while the Sierra Blanca Mill site is fenced, owned by the Town of Carrizozo, and available for reuse.

The EPA completed its sixth Five-Year Review in July 2023, and the next review is scheduled for 2028. Community members with questions about the site or the deletion process can contact the EPA's Remedial Project Manager or Community Involvement Coordinator using the information below. The review report is available for public review through the EPA's Superfund database.