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Hard-rock Mining and Migratory Birds

Date Posted: September 26, 2001

Some of the nation’s largest open-pit copper mines, and their associated mills and smelters have been a part of the New Mexico landscape for over 100 years. Smelter emissions along with numerous by-products of the mining process, including ore leach piles (piles of ore that have had a concentrated solution of sulfuric acid dripped over them to dissolve out the copper), waste-rock dumps, and tailings (finely grained waste) have affected vast areas of land and water. The tailings, large amounts of processing water, and concentrated leach solutions are discharged continuously from the ore processing plant and leach piles into pond-like areas. These tailings and leach solution ponds attract shorebirds and waterfowl to drink, rest, and at some ponds, to feed on metal contaminated plants and invertebrates. The pond water also is often highly acidic and toxic to birds and other wildlife that use these ponds as a drinking water source. In addition, temporary tributaries and creeks draining the hard-rock mines are often heavily contaminated with metals from frequent spills of tailing slurries, sulfuric acid leach solutions, and storm-water runoff. Numerous birds of prey, including eagles and hawks, nest in the uplands and feed on the small birds, waterfowl, rodents, and reptiles that frequent the mine-waste contaminated areas. The New Mexico Field Office’s Environmental Contaminants (EC) Program is concerned about the risks to waterfowl using contaminated wetlands, and the possibility that birds of prey may be harmed by eating birds, reptiles and rodents using the contaminated areas. The EC Program is working with the Environmental Protection Agency, State of New Mexico, Bureau of Land Management, the Service’s Division of Law Enforcement, and the mine operators to develop ways of evaluating the risks to wildlife and eliminating or minimizing those risks.

Russ MacRae, 505-346-2525.

Last updated: June 12, 2015