Cyanide at the proposed Idaho Maryland Mine
Basic Facts about Cyanide use at IMM
Cyanide is a highly toxic, environmentally dangerous chemical used to process ores at mines.(1) Emgold, wants to use cyanide at its proposed IM mine, near Wolf Creek - despite the fact that alternatives to cyanide are being used at similar mines.
Emgold plans to dispose of waste cyanide in processed mine rock and underground in the mine as fill.(2) This plan places drinking water and streams and rivers such as Wolf Creek at risk. A cyanide spill in 2000 in one of Europe's foremost fishing rivers led to concern around the world; cyanide bans in mining have been passed in Montana, the Czech Republic, and parts of Wisconsin. (1)
Extremely small amounts of cyanide are deadly to fish. The federal standard for aquatic life is 5 parts per billion. A mine waste spill into Wolf Creek or via leaching into the SF Bay Delta could be catastrophic to fish and other wildlife.
Shipping cyanide to the proposed IM mine or other mines could lead to accidents. IMM proposes to ship 2.67 tons of cyanide to the mine each month. (2) Research has found at least 23 transportation-related spills of cyanide in the U.S. in the ten years ending in 1997. (1)
Cyanide spills and pollution from modern mines is not uncommon. At mines in Nevada and Arizona, over a four-year time span through the end of 2000, cyanide spilled twice and caused a major mine waste spill in 1997 that covered three quarters of a mile of Pinto Creek in Arizona and cost more than $30 million to clean up. (1) Problems with cyanide in mining are not only during the ore processing, which separates the metal from the ore, but also with the transportation of cyanide before the processing, and the storage of cyanide wastes after the processing.
Detailed Facts about Cyanide usage in mining
Description of Cyanide use at IMM direct from IMM documents
The following is taken from the IMM Initial Study, Sept 2007 p. 3-29. The combined tailings (from flotation and cyanide leaching) are then thickened to remove water. A portion of the tailings would be sent underground for use as backfill. The remaining portion of the tailings would be dewatered and sent to the ceramics plant to make tile products. The ultimate mining rate proposed is 2,400 STPD (standard tons per day), of which 800 to 1,200 STPD would be development rock. The gold processing plant would handle 2,400 STPD through the crushing and processing circuits. The ceramics plant would be capable of handling 1,200 STPD of feed, allowing for up to 1,200 STPD of material to be returned underground as backfill; however, some material could be sold as aggregate and trucked off-site.
Op cit p. 3-33. Sodium cyanide would be transported to the Idaho-Maryland site approximately once every three weeks in granular or powder form in one- to two-ton "super sacks" that are lined, unbreakable nylon sacks designed to be handled by forklifts.(Over a 20 year span that results in over 340 trips) As an alternative, a 24 percent to 32 percent sodium cyanide in water mixture may be used instead. This solution would be transported in a double-walled 4,000 gallon container trucks. Acids would be stored in a separate lined and bunded (sic) area to prevent formation of hydrogen cyanide (HCN) gas. Spillage from the respective storage areas would be directed to separate area sumps isolated and at a distance from each other and evacuated on a regular basis. Potential releases of hazardous materials stored at the site would be characterized to determine appropriate disposal requirements in accordance with California Health and Safety Code Chapter 6.95; in accordance with these regulations, the project applicant would prepare and implement a Hazardous Materials Business Plan.
(1) Background on Mining Bills - Senate Bill 160 Ban on Cyanide In All Wisconsin Mines http://treaty.indigenousnative.org/cyanide.html