Montana is the only state in the nation to have a ban on cyanide heap-leach mining. MEIC also reached around the world to Argentina to help citizens there pass a first-of-its-kind ban on cyanide-leach gold mining in the watershed of the city of Esquel, Chubut Province, Patagonia.

There are three primary reasons Montana is phasing out -- and has banned new -- open pit, cyanide-leach mining in Montana:

• Landowners downstream of the Golden Sunlight mine were forced to sell their property to Placer Dome Corp. after their drinking water well was contaminated with cyanide.

• The Kendall mine near Lewistown has contaminated neighboring ranchers' streams with toxic mine waste since 1995. Reclamation efforts at the mine have also depleted downstream water supplies. Eight neighboring landowners have filed water rights complaints against the company.
• The Golden Maple mine near Lewistown was ordered to provide a neighboring rancher with an alternate water supply for both domestic and stock water needs after 77,000 gallons of cyanide contaminated area groundwater.

• Pegasus Gold Corp. declared bankruptcy in 1997 leaving the State with insufficient funds to reclaim the Zortman/Landusky mine, Montana's largest gold mine. The State has estimated that water treatment will have to occur at the mine site in perpetuity.
• State officials have also determined that the reclamation bond at Canyon Resource's Kendall mine in Lewistown is inadequate to pay for long-term water treatment. The State estimates that an additional $3.5 million will be necessary.
• Cyanide, heavy metals and acid mine drainage from the Summitville mine in Colorado killed all aquatic life in 17 miles of the Alamosa River. The company declared bankruptcy in 1992. As of 1996, the EPA has spent over $100 million in on-going cleanup efforts.

• Since 1982, there have been 50 cyanide releases at Montana mines, releasing millions of gallons of cyanide solution into Montana's soil, surface and groundwater resources.
• Cyanide can persist for very long periods of time in ground water because the sunlight and oxygen needed to break it down to less harmful substances are largely absent. Groundwater contamination is the most prevalent form of cyanide contamination at Montana's open pit cyanide leach mines because the liner systems designed to prevent this type of occurrence are not impermeable and are prone to structural damage (punctures or tears).
• In a 1997 lawsuit settlement against Pegasus Gold, the company agreed to spend $34 million to study environmental damage to the groundwater surrounding the Zortman/Landusky mine, to construct an additional water treatment plant, to conduct a public health study, and other measures.
• In 1998, 800 people were hospitalized in Kyrgyzstan after a major cyanide spill. A peer-reviewed, scientific report entitled "Cyanide Uncertainties," released in 1998 concluded that cyanide may form compounds that are toxic to aquatic life, may persist for long periods of time, and accumulate in plant or fish tissue. when mine operators test for cyanide, they are not required to test for these breakdown compounds. these compounds are unregulated despite the environmental or public health impacts.