Fact Pack

Health Concerns

Cyanide is highly toxic. Cyanide poisoning can occur through inhalation, ingestion, and skin or eye contact. Cyanide blocks the absorption of oxygen by cells, effectively causing the victim to suffocate.(1) One teaspoon of a 2% cyanide solution can kill a person.(1) In general, fish and other aquatic life are killed by cyanide concentrations in the microgram per liter (part per billion) range, whereas bird and mammal deaths result from cyanide concentrations in the milligram per liter (part per million) range.(2) Chronic cyanide exposure may affect reproduction, physiology, and levels of activity of many fish species, and may render the fishery resource non-viable.(2)

Both cyanide and acid-mine drainage can find their way into streams and rivers through accidental spills, discharges, dam overflows, and water runoff. It can also seep into groundwater.(3) Leftover cyanide in very small concentrations can harm birds and other wildlife that drink mine pond wastewater.(4)

Cyanide is a powerful solvent that breaks down heavy metals – such as mercury, cadmium, chromium, and lead – that end up as waste products that need to be dumped. Cyanide can also break down and form complexes with other metals or chemicals. These mixes of cyanide with other metals and chemicals can be just as toxic as cyanide itself, but they are not routinely monitored or carefully regulated.(4)

Uncertainty

Special thanks to the Mineral Policy Center for providing the information in this section.(2)

Cyanide compounds are widely used by the mining industry to assist in the extraction of metals from rock. In gold mining, a dilute cyanide solution is sprayed on crushed ore that is placed in piles (heaps), or mixed with ore in enclosed vats. The cyanide attaches to minute particles of gold to form a water soluble, gold-cyanide compound from which the gold can be recovered. Cyanide is used in a similar manner to extract silver from ores. In the extraction of non-precious metals, such as copper, nickel, cobalt, and molybdenum, cyanide is used in the milling and concentration processes to separate the desirable metals from the wastes. Consequently, cyanide and related compounds often are contained in discarded mine wastes.

The use of cyanide compounds by the mining industry, along with limitations in the analysis and monitoring of these compounds, raises serious concerns regarding environmental protection and public safety at mine sites using cyanide processing.

According to the Mineral Policy Center, “mining and regulatory documents often state that cyanide in water rapidly breaks down in the presence of sunlight into largely harmless substances, such as carbon dioxide and nitrate or ammonia. However, cyanide also tends to react readily with many other chemical elements and is known to form, at a minimum, hundreds of different compounds.” Many of these breakdown compounds are generally less toxic than the original cyanide, but are still known to be toxic to aquatic organisms. These breakdown compounds may persist in the environment for an unknown period of time, and there is evidence that some forms of these compounds can accumulate in fish and plant tissues.

Despite the apparent risks posed by these cyanide-related breakdown compounds, regulatory agencies do not require mine operators to monitor this group of chemicals in mining-related waters. While much of the cyanide used at mining sites does break down fairly readily, either as a result of natural degradation or the various treatment processes sometimes employed, significant amounts of the original cyanide form potentially toxic compounds that remain unaccounted for in the monitoring of mining operations.

The unique chemical behavior and toxic nature of these compounds, combined with the risk of serious mine waste spills, suggest that there are persisting uncertainties which merit closer study.

Private Property Rights and Tax Dollars

Special thanks to the Montana Environmental Information Center for providing the information in this section.(5)

Open pit cyanide leach mines threaten the private property rights of neighboring landowners.

• Before a voter initiative banned the use of cyanide in open pit, cyanide-leach mining in November 1998, Montana landowners downstream of the Golden Sunlight mine were forced to sell their property to Placer Dome Corporation after their drinking water was contaminated with cyanide.
• The Kendall mine near Lewistown, Montana, has contaminated neighbors’ streams with toxic mine waste since 1995. Reclamation efforts at the mine have also depleted water supplies downstream from the company. Eight neighboring landowners have filed water rights complaints against the mining company.
• The Golden Maple mine near Lewistown, Montana, 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 the neighbor’s groundwater.

Furthermore, when a mining corporation declares bankruptcy, taxpayers are left with the economic burden of reclamation, leaving liabilities for future generations.

• Cyanide, heavy metals, and acid mine drainage from the Summitville mine in Colorado killed all aquatic life throughout 17 miles of the Alamosa River. The company declared bankruptcy in 1992, and the U.S. Environmental Protection Agency has spent over $170 million in on-going cleanup efforts.
• In 1997, Pegasus Gold Corporation declared bankruptcy, 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 site in perpetuity.
• State officials have determined that the reclamation bond at Canyon Resource’s Kendall mine in Lewistown, Montana, is inadequate to pay for long-term water treatment. The state estimates that at least an additional $3.5 million will be necessary.

Open pit, cyanide-leach mines consistently contaminate water resources with cyanide and other pollutants placing human and environmental health at risk.

• 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.

New Possibilities

The use of cyanide is not necessary in many types of mining. In 1999, 16 of 18 leading U.S. zinc mines and 11 of 15 leading U.S. copper mines did not use cyanide.(6) In the gold extraction process, however, cyanide is used to retrieve 90% of gold mined in the U.S.(7) Emerging science, spurred by the desire to make economically feasible, more environmentally friendly alternatives, has developed new technologies that may make cyanide use unnecessary in all mining processes.

Many people have proposed alternatives to the use of cyanide in mining, but most have been rejected by industry because of high cost or ineffectiveness. However, Norman Haber of Haber, Inc. has developed a new method of mineral extraction using non-toxic, cost-effective alternatives. The Haber Gold Process (HGP) has undergone preliminary and follow-up testing by mining engineering groups, which have concluded that HGP results in more gold recovery over a shorter period of time than the cyanide leaching processes with a cost comparable to, or less than, cyanide leaching. In addition, HGP passed the California Department of Health Services Acute Aquatic Toxicity Bioassay test, which tests the toxicity of a substance on wildlife. Passing the test requires that not more than 50% of the aquatic life dies when a substance is introduced into its water environment. HGP resulted in an 85 to 100 percent survival rate.(8) These claims are made by the Haber Inc. web site and, although independent testing of HGP has been done, there are no public documents that can verify these claims.

In addition, the cyanide-free biocatalyzed leaching process from YES Technologies uses a bisufide leaching agent which is 200 times less toxic than cyanide. Preliminary test results indicate chemical reagent costs associated with this process could be 80% lower than cyanide.(9)

(1) Project Underground. “The Gold Album.” 19 February 2004 <http://www.moles.org/ProjectUnderground/reports/goldpack/goldpack_a.html>.
(2) Moran, Robert. “Cyanide Uncertainties: Observations on the Chemistry, Toxicity, and
Analysis of Cyanide in Mining-Related Waters.” 1998. Mineral Policy Center. 20 February 2004 <http://www.mineralpolicy.org/publications/pdf/cyanideuncertainties.pdf>.
(3) Huff, Andrew. “Gold mining threatens communities.” 11 July 2000. The Progressive. 20 February 2004 <http://www.progressive.org/mpdvah00.htm>.
(4) Blouin, Dave. “Crandon Proposal: Cyanide Issues.” February 2000. Wisconsin Stewardship Network. 20 February 2004 <http://www.wsn.org/mining/Cyanidebackground.html>.
(5) “MEIC Passes Initiative to Prohibit Open Pit Cyanide Heap-Leach Mining.” Montana Environmental Information Center (MEIC). Last updated February 16, 2004. 18 February 2004 <http://www.meic.org/i137background.html>.
(6) “Wisconsin Campaign to Ban Cyanide in Mining.” Wisconsin Stewardship Network. 20 February 2004 <http://www.wsn.org/mining/cyanidepoints1.pdf>.
(7) Mineral Policy Center. “Cyanide Leach Mining Packet.” August 2000. 24 February 2004 <http://www.mineralpolicy.org/publications/pdf/Cyanide_Leach_Packet.pdf>.
(8) “Haber Gold Process (HGP) - The Technology.” Haber. 20 February 2004 <http://www.demo.haberscience.com/HGP%20-%20The%20Technology.htm>.
(9) “Cyanide-free Biocatalyzed Leaching of Gold and Silver Ore.” YES Technologies. 19 February 2004 <http://yestech.com/tech/gold1.htm>.