Frequently Asked Questions
Q. What is cyanide?
A. Cyanide refers
to a group of compounds made of carbon and nitrogen. Cyanide solutions
readily bond with gold, silver and other metals, which is why the
mining industry uses it. Cyanide is usually stored and transported
as a solid. It is stable when dry. Most cyanide solids will dissolve
in water to produce toxic cyanide gas. Cyanide gas is colorless
and smells like bitter almonds. Cyanide is produced naturally in
minute, harmless quantities in several plants, such as in apple
seeds, apricot pits, soil bacteria and species of invertebrate organisms.
Q. How does cyanide
affect living organisms?
A. Cyanide is highly
toxic. Cyanide is the killing agent used in gas chambers. Cyanide
poisoning can occur through inhalation, ingestion, and skin or eye
contact. One teaspoon of a 2% solution can kill a person. 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. A cyanide spill in Romania on
January 30th, 2000, killed thousands of tons of fish and made a
significant portion of the Tisza River watershed undrinkable and
hostile to aquatic life. Evidence shows that cyanide compounds linger
in affected plant and fish tissues and can persist in the environment
for long periods of time.
Q. How is cyanide
used in mining?
allows mining companies to reopen and expand mines containing what
were previously unprofitable mineral reserves. There are two types
of cyanide-leaching processes used by the modern mining industry.
Vat-leaching, where extracted ore is combined with cyanide in vats,
and heap-leaching, which involves:
- Digging enormous pits (often larger than some cities) and piling
the extracted ore into heaps that would cover many football fields
several hundred feet high;
- Spraying a cyanide solution over the heaps so that the cyanide
trickles down through the ore, bonding with microscopic flecks
of gold or silver, whereupon a heap pad (a rubber blanket), underlying
the heap, channels the solution into a holding pond; and,
- Stripping the solution of the precious minerals, recovering
the used cyanide, then respraying the cyanide solution over the
In the extraction of copper, nickel, cobalt and
molybdenum, cyanide is used during the milling and concentration
Q. What are the
dangers of using cyanide?
A. Cyanide reacts
with many other elements and is known to breakdown into several
hundred different cyanide-related compounds. Despite the risks posed
by these breakdown compounds, mines are not required to monitor
or report these chemicals.
Cyanide-leaching, as practiced by the modern mining
industry, is inherently dangerous to the environment and the communities
surrounding a mine that uses the process. As cyanide use continues,
so do serious accidents and spills. Four recent examples are:
- Zortman-Landusky Mine, Montana, 1982: Fifty-two thousand gallons
of cyanide solution poison the drainage that supplies fresh drinking
water for the town of Zortman. A mine employee discovered the
accident when he noticed the smell of cyanide in his tap water
- Summitville Mine, Colorado, 1992: Summitville gold mine was
responsible for contaminating 17 miles of the Alamosa River with
cyanide and other contaminants.
- Kumtor Gold Mine, Kyrgyzstan, central Asia, 1998: A truck carrying
2 tons of sodium cyanide crashed into the Barskoon River. Two
thousand six hundred poison cases and 4 deaths were reported in
- Aural Gold Plant, Romania, Eastern Europe, 2000: A cyanide-laden
tailings spill sent a toxic slug of cyanide and metals rolling
down the Tisza River and into the Danube, killing aquatic wildlife
and poisoning water supplies as far as 250 miles downriver.
Q. Does society
require we use cyanide to supply gold?
A. Probably not.
Potential cyanide-mining substitutes aside, we may not need to use
cyanide in gold mining simply because there are already enormous
supplies of gold, already mined and refined, above ground in reserve
banks (like the Federal Reserve in the U.S.). Reserve banks and
international financial institutions store more than 34,000 tons
of gold as currency reserves, an amount equivalent to nearly one-quarter
of all gold ever mined. A dollar used to be redeemable for a dollar’s
worth of gold. That is no longer the case now; gold reserves are
an anachronism of a past era. Meanwhile, 34,000 tons of gold could
satisfy current global demand for 8 years. (85% of the gold demand
is for jewelry, only 12% for industry.) Moreover, by holding these
gold reserves, central banks are costing taxpayers money. The U.S.,
the world’s largest holder of gold reserves, has lost $215
billion since 1980 due to plummeting gold prices, and we stand to
lose more if other governments sell their gold reserves first, which
is already happening. Reserve banks in the Netherlands, Switzerland,
the UK, and Australia have already sold or decided to sell significant
portions of their gold reserves.
Q. Is cyanide
safe, and is it necessary?
A. Despite mining
industry assertions to the contrary, the record clearly demonstrates
that cyanide leach mining is not being practiced safely. It is potentially
very dangerous to the environment, wildlife, and humans. The hardrock
mining industry has a history of cyanide spills, with billions of
gallons of cyanide contamination released into the environment,
ever since cyanide-leaching began in the 1970s. Furthermore, cyanide-mining
may not be necessary. Enormous stockpiles of unused gold already
exist above ground in reserve banks around the world.
Q. Are there alternatives
A. The U.S. Environmental
Protection Agency lists several alternatives to cyanide, including
starch and sulfur dioxide. In 1999, 16 of 18 leading U.S. zinc mines
and 11 of 15 leading U.S. copper mines did not use cyanide.
For gold and silver extraction, the Haber Gold Process
(HGP) has been proposed as a possible alternative. 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. 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.