# State ofNew Mexico Office 

# 1 die §overnor Bill Richardson Governor October 25,2010

AlArmendariz, RegionalAdministrator U.S. Environmental ProtectionAgency, Region 6 1445 Ross Avenue, Suite 1200 Dallas, TX 75202-2733
RE: Proposal to Include the Molycorp, Inc. Site, Taos County, NewMexico, onthe National Priorities List (EPA ID: NMD002899094)

. DearMr. Armendariz: Bythis letter, the State ofNewMexico expresses its support for adding the Molycorp, Inc. site, also known as the Questa Mine site, located nearthe Town ofQuesta, Taos County, NewMexico, on the National Priorities List (NPL) for remedial actionpursuantto section 105(a)(8)(B) ofthe Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), 42 U.S.C. § 9605(a)(8)(B). CERCLAremedial action at the site is necessary to protect human health andthe environment. The State ofNewMexico initially supported inclusion ofthe Molycorp, Inc. site on the NPL by letter from then Governor Gary E. Johnson, dated April 1, 2000. The Environmental Protection Agency (EPA) proposed the site for the NPL on May 11,2000. 65 Fed. Reg. 30,489. This letter reaffirms the State ofNewMexico's concurrence with the final listing ofthe Molycorp, Inc. site on the NPL.
Due to a corporate acquisition, the Molycorp, Inc. site is now operatedby Chevron Mining Inc. (CMI), and has been renamed the CMI Questa Mine. The site consists ofthe mine site and milling facility, and the tailing ponds. The mine site and milling facility is located four miles east ofQuesta, and the tailings impoundments are located one mile west ofQuesta. A nine-mile long pipeline running along State Highway 38 and the Red River connects the milling facility to the tailings ponds. The mine site and milling facility is located on approximately three square miles ofland and the tailing impoundments encompass approximately two square mile ofland. Mining operations at the site began in 1920 and are ongoing. Openpit mining was conducted from 1965 to 1983 and resulted in over 328 million tons ofacid generating and potentially acid-generating waste rock being

, placed into nine piles surrounding the open pit. Mining is currentlyperformedunderground. Over

100 million tons oftailing have been disposed ofin the tailing impoundments.

/ State Capitol • Room 400 • SantaFe, New Mexico 87501 • 505-476-2200 • www.governor.state.nm.usAl Armendariz October 25,2010 Page 2 of2

Over the years numerous breaks in the pipeline resulted inthe release oftailings into and along the flood plain ofthe Red River. The remedial investigation performed for the site confirms that tailing seepage and runofffrom the tailingponds have caused ground water and soil contamination with hazardous substances at levels that pose a risk to health and the environment. In addition, ground water and surface water have been adversely impactedby seepage ofacidic metals-laden water generated from the weathering ofthewaste rock piles (referred to as acid rock drainage or ARD) at the mine site. Contaminants ofconcern include aluminum, antimony, arsenic, beryllium, cadmium, chromium, cobalt, fluoride, iron, manganese, molybdenum, nickel, sulfate (a precursorto the formation ofsulfuric acid, which is a primary component ofARD), vanadium and zinc. Listing the Molycorp, Inc. site on the NPL would allow use ofthe Hazardous Substance Superfund to fund remedial activities and clean-up the site in the event that potentiallyresponsible parties are not willing or able to fund remedial activities. Given that the site poses a threat to public health and the environment and, in particular, given that it threatens ground water quality which must be preserved for future generations, the State ofNewMexico strongly supports the addition ofthe Molycorp, Inc. site to the NPL. The State ofNewMexico looks forward to continuing to work closely with EPA on this site to ensure the protection ofhuman health and environment. Sincerely,

Bill Richardson Governor

cc: Sam Coleman, Superfund Division, EPARegion 6 Ron Curry, Secretary, NewMexico Environmental Department and NewMexicoNatural Resources Trustee