![[logo] US EPA](http://www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}
NPL Site Narrative for Molycorp, Inc.
MOLYCORP, INC.
Questa, New Mexico
Federal Register Notice: May 11, 2000The Molycorp, Inc., site encompasses two distinct areas, a molybdenum mine and its associated tailings ponds, both of which are located near the town of Questa, Taos County, New Mexico. The mine is located 4 miles east of Questa on approximately 3 square miles of land owned by Molycorp. The tailings ponds are located 6 miles west of the mine on approximately 1 square mile of land also owned by Molycorp. The mine is surrounded by the Carson National Forest and is approximately 2 miles from the Latir Peak Wilderness Area. The Red River, which is located immediately south of the mine and tailings ponds, flows in a westerly direction into the Rio Grande River approximately 3 miles downstream of the tailings ponds. The site is being proposed to the NPL because of the threat to the Red River fishery and nearby endangered species habitats from uncontrolled acidic, metal laden runoff from the mine and the tailings ponds. Contaminants of concern include metals such as arsenic, cadmium, chromium, cobalt, lead, manganese, and zinc.
Small-scale underground mining operations began at the mine in 1920. The underground workings grew and by 1954 the underground complex contained over 35 miles of mine workings. The original underground mine continued to grow until an open pit was developed in 1965. During open pit mining operations, approximately 328 million tons of potentially acid generating waste rock were excavated and deposited in large piles surrounding the mine. After the molybdenum was extracted at the mine through milling and concentrating operations, tailings and water were transported to the tailings ponds via a 9-mile long pipeline. Reportedly, up to 80 spills from the pipeline, which runs parallel to and within a few feet of the Red River, occurred between 1966 and 1976. It is estimated that 95 million tons of fine-grained tailings have been deposited in the four tailings ponds.
In 1966, a year after open pit mining began at the site, the U.S. Department of Health, Education, and Welfare conducted a baseline water quality survey of the Red River and determined that the overall quality, including the segment adjacent to Molycorp mine, was high. In November 1971, the U.S. Environmental Protection Agency (EPA) conducted a study of the Red River and concluded that the chemical quality and biological conditions of the Red River remained very good, but that occasional breaks in the Molycorp tailings pipelines resulted in some degradation of river quality. Also in the early 1970s, the New Mexico Game and Fish Department discovered in the course of routine population studies, that fish were conspicuously absent in the middle reach of the Red River where thriving populations once existed. Beginning in the early 1980s, EPA and the Federal Bureau of Land Management (BLM) began documenting major impacts to the Red River due to mining and mining-related activities. In 1992, the New Mexico Water Quality Control Commission submitted a report to the United States Congress documenting elevated levels of numerous metals within the vicinity of the Molycorp mine, including cadmium, copper, lead, silver, and zinc. Since that time, four subsequent reports were prepared and submitted by various state and Federal agencies, all further establishing significant metals contamination in the Red River due to uncontrolled runoff from the mine and to seepage from contaminated ground water that also has been affected by mining operations.
Both the shallow ground water and surface waters draining the site, like the Red River, have become contaminated with acidic, metal laden waters due to mining operations. Although Molycorp currently has a water management and sediment collection program in place, storm events and contamination that occurred prior to the implementation of these programs has greatly impacted the area. The Red River, a once-popular multiple use watershed, continues to be a fishery and is home to a state fish hatchery located 3 miles downstream of the site. In addition, the river provides water for irrigation and livestock watering, and serves as a wildlife habitat. In 1983, the Red River and the Rio Grande River in the vicinity of their confluence were designated as a Wild and Scenic River by the BLM. The mine is surrounded by the Carson National Forest and is approximately 2 miles from the Latir Peak Wilderness Area. Furthermore, numerous wetlands have been documented in the area by the U.S. Fish and Wildlife Service, and several threatened or endangered species may live near the site, including the bald eagle.
For more information about the hazardous substances identified in this narrative summary, including general information regarding the effects of exposure to these substances on human health, please see the Agency for Toxic Substances and Disease Registry (ATSDR) ToxFAQs. ATSDR ToxFAQs can be found on the Internet at http://www.atsdr.cdc.gov/toxfaq.html or by telephone at 1-888-42-ATSDR or 1-888-422-8737.