Repeal of the Ban on Cyanide Heap Leaching in Gold Mining
WHAT IS CYANIDE AND WHAT DOES IT DO IN THE ENVIRONMENT
Cyanide is a general term, referring to various specific cyanide compounds. Cyanide (CN) itself is a simple, organic anion (negatively charged ion) consisting of carbon and nitrogen. Despite often-heard references to “pure cyanide,” it actually exists only as an anion, so is only a component of other compounds.
Even though cyanide is a poison, trace amounts of cyanide compounds occur naturally in our bodies and in many foods. Even over a lifetime of exposure, trace amounts pose no threat to human health. Cyanide does not build up in the body. The liver removes it. As one might expect, cyanide compounds are used in certain herbicides. But some common drugs—including the pain reliever ibuprofen and the anti-inflammatory agent naproxen—also contain cyanide compounds, or are derived directly from them.
Today, U.S. chemical manufacturing industries consume more than 10 times the amount of cyanide compounds than are used in domestic gold mining to manufacture products like nylon and other polyamides, acrylics and certain plastics. Cyanide compounds are also used to harden steel and to electroplate copper and precious metals.
Cyanide heap leach solutions are very alkaline because at a ph of 8 or below CN vaporizes into the air. In the air, the poison is quickly dispersed and would only be dangerous in a very small area close to the vaporizing solution. Therefore if these solutions do escape into surface water, they will be diluted by the lower ph surface water and soon dissipate into the air, becoming harmless.
Other natural elements including sunlight also degrade cyanide into harmless compounds:
“Various species of bacteria, fungi, algae, yeasts and plants, along with their associated enzymes and amino acids, are known to oxidize cyanide naturally.”
HOW DOES CYANIDE LEACHING WORK
A weak solution containing a quantity of sodium cyanide (0.015 percent average) is percolated over crushed ore to dissolve the gold. The leach solutions are carefully buffered with an alkali (usually lime) to prevent the possible generation of hazardous hydrogen cyanide gas. The gold bearing solution is collected and the gold removed. The leaching solution is then reused. The whole process takes place on top of an impermeable, double or triple layered liner to collect all of the valuable gold and prevent the escape of dangerous CN.
POLITICAL HISTORY OF CYANIDE LEACHING
In 1996, environmental groups headed by MEIC from Missoula launched an attack on mining through the initiative process. Miners defended their industry and I-122 was defeated. A great deal of out of state money was spent on this campaign by both sides. There was another ballot issue that year: I-125, sponsored by MontPIRG which is a Nader group that percolated up from the Univerity of Montana campus at Missoula. I-125 prevented businesses spending ANY money to defend themselves against ballot issues. In the heated battle over I-122, this seemingly innocuous ballot issue was overlooked by business and the public. I-125 did not put any limitations on spending by non-profit groups on Montana ballot issues. I-125 passed in 1996.
After the passage of the business spending ban, I-125, MEIC decided that they had a good chance to pass an anti-mining bill in the next election because the miners could not fight back. They said as much on their website. This time they sensationalized the issue by concentrating on cyanide. Just two weeks before the election the Montana Supreme Court ruled that the ban on business spending in ballot issue elections was unconstitutional but it was too late for the miners to mount an effective defense. I-137 passed in 1998. No other state in America bans the use of cyanide in mining.
BENEFITS
Mining in Montana has rapidly declined in recent years due to the regulatory climate in the state. Since cyanide leaching is the only economic means of recovering many of Montana’s most important gold and silver deposits, repealing the cyanide ban will go a long way towards improving that climate thus helping to diversify our economy. Canyon Resources lists the economic losses to Montana from the passage of the cyanide ban just related for their projects alone.
“The imposition of I-137, with its total ban on the use of the only economically viable technology to recover gold and silver from the McDonald and Seven-Up Pete deposits, has deprived the citizens of Montana, local communities and their workers, and the State of Montana of the following otherwise available assets:
a. Royalty payments of more than $89 million ($6,357,142 annually for 14 years) to the State School Trust System, primarily designated for Montana Tech
b. Long-term jobs at wages approximately twice the current average income in Montana
c. Severance and local taxes of at least $56 million
d. More than $1 billion (average of $75 million/year) in purchases of goods and services during operations
e. More than $40 million in site construction work at startup”
Cyanide is a general term, referring to various specific cyanide compounds. Cyanide (CN) itself is a simple, organic anion (negatively charged ion) consisting of carbon and nitrogen. Despite often-heard references to “pure cyanide,” it actually exists only as an anion, so is only a component of other compounds.
Even though cyanide is a poison, trace amounts of cyanide compounds occur naturally in our bodies and in many foods. Even over a lifetime of exposure, trace amounts pose no threat to human health. Cyanide does not build up in the body. The liver removes it. As one might expect, cyanide compounds are used in certain herbicides. But some common drugs—including the pain reliever ibuprofen and the anti-inflammatory agent naproxen—also contain cyanide compounds, or are derived directly from them.
Today, U.S. chemical manufacturing industries consume more than 10 times the amount of cyanide compounds than are used in domestic gold mining to manufacture products like nylon and other polyamides, acrylics and certain plastics. Cyanide compounds are also used to harden steel and to electroplate copper and precious metals.
Cyanide heap leach solutions are very alkaline because at a ph of 8 or below CN vaporizes into the air. In the air, the poison is quickly dispersed and would only be dangerous in a very small area close to the vaporizing solution. Therefore if these solutions do escape into surface water, they will be diluted by the lower ph surface water and soon dissipate into the air, becoming harmless.
Other natural elements including sunlight also degrade cyanide into harmless compounds:
“Various species of bacteria, fungi, algae, yeasts and plants, along with their associated enzymes and amino acids, are known to oxidize cyanide naturally.”
HOW DOES CYANIDE LEACHING WORK
A weak solution containing a quantity of sodium cyanide (0.015 percent average) is percolated over crushed ore to dissolve the gold. The leach solutions are carefully buffered with an alkali (usually lime) to prevent the possible generation of hazardous hydrogen cyanide gas. The gold bearing solution is collected and the gold removed. The leaching solution is then reused. The whole process takes place on top of an impermeable, double or triple layered liner to collect all of the valuable gold and prevent the escape of dangerous CN.
POLITICAL HISTORY OF CYANIDE LEACHING
In 1996, environmental groups headed by MEIC from Missoula launched an attack on mining through the initiative process. Miners defended their industry and I-122 was defeated. A great deal of out of state money was spent on this campaign by both sides. There was another ballot issue that year: I-125, sponsored by MontPIRG which is a Nader group that percolated up from the Univerity of Montana campus at Missoula. I-125 prevented businesses spending ANY money to defend themselves against ballot issues. In the heated battle over I-122, this seemingly innocuous ballot issue was overlooked by business and the public. I-125 did not put any limitations on spending by non-profit groups on Montana ballot issues. I-125 passed in 1996.
After the passage of the business spending ban, I-125, MEIC decided that they had a good chance to pass an anti-mining bill in the next election because the miners could not fight back. They said as much on their website. This time they sensationalized the issue by concentrating on cyanide. Just two weeks before the election the Montana Supreme Court ruled that the ban on business spending in ballot issue elections was unconstitutional but it was too late for the miners to mount an effective defense. I-137 passed in 1998. No other state in America bans the use of cyanide in mining.
BENEFITS
Mining in Montana has rapidly declined in recent years due to the regulatory climate in the state. Since cyanide leaching is the only economic means of recovering many of Montana’s most important gold and silver deposits, repealing the cyanide ban will go a long way towards improving that climate thus helping to diversify our economy. Canyon Resources lists the economic losses to Montana from the passage of the cyanide ban just related for their projects alone.
“The imposition of I-137, with its total ban on the use of the only economically viable technology to recover gold and silver from the McDonald and Seven-Up Pete deposits, has deprived the citizens of Montana, local communities and their workers, and the State of Montana of the following otherwise available assets:
a. Royalty payments of more than $89 million ($6,357,142 annually for 14 years) to the State School Trust System, primarily designated for Montana Tech
b. Long-term jobs at wages approximately twice the current average income in Montana
c. Severance and local taxes of at least $56 million
d. More than $1 billion (average of $75 million/year) in purchases of goods and services during operations
e. More than $40 million in site construction work at startup”
With the lifting of the ban Canyon and other companies would resume exploration in Montana and new projects as well as old ones that have been put on hold will strengthen our economy with royalties, taxes, jobs and sales for related businesses. The $ 89 million royalty from the Seven Up Pete project alone spread over 14 years will amount to 10% of the total current yearly income for Montana schools from state trust lands
DRAWBACKS
There are no drawbacks - only risks that can be managed. Like bleach and gasoline, Cyanide (CN) is a deadly poison when a toxic amount is present in the blood of mammals and fish. Therefore extra care must be taken in the handling and containment of cyanide solutions. I-147 mandates a high level of environmental protection.
Since cyanide degrades into non-toxic substances fairly easily and is quickly dispersed and diluted in the natural environment the damage from escaped cyanide though it can be significant is thankfully short term. Humans who ingest a non-fatal dose of cyanide quickly recover and there is no evidence of long-term consequences or buildup of cyanide in the body. There has never been a human fatality in Montana caused by cyanide used in mining.
There have been fish kills due to accidental releases of cyanide from mining. Most of these incidents have been minor and none of them have long lasting effects. Our research found no major fish kills in Montana. The fish stocks are repopulated from unaffected downstream fisheries. The mining industry and the agencies that regulate them have learned from these incidents and are better equipped to prevent them.
DRAWBACKS
There are no drawbacks - only risks that can be managed. Like bleach and gasoline, Cyanide (CN) is a deadly poison when a toxic amount is present in the blood of mammals and fish. Therefore extra care must be taken in the handling and containment of cyanide solutions. I-147 mandates a high level of environmental protection.
Since cyanide degrades into non-toxic substances fairly easily and is quickly dispersed and diluted in the natural environment the damage from escaped cyanide though it can be significant is thankfully short term. Humans who ingest a non-fatal dose of cyanide quickly recover and there is no evidence of long-term consequences or buildup of cyanide in the body. There has never been a human fatality in Montana caused by cyanide used in mining.
There have been fish kills due to accidental releases of cyanide from mining. Most of these incidents have been minor and none of them have long lasting effects. Our research found no major fish kills in Montana. The fish stocks are repopulated from unaffected downstream fisheries. The mining industry and the agencies that regulate them have learned from these incidents and are better equipped to prevent them.