Gold Mining: The Environmental Concerns

The greatest environmental concern associated with gold mining is the disposal of the significant amount of overburden that is removed from the mines. Most countries have laws which requiring that mining sites be restored to their original contours. The legislation also required that a mining operator submit a plan for restoring the land and for mitigating acid mine drainage before a permit would be granted to begin mining operations.

The use and disposal of cyanide solutions used to dissolve and extract gold from ore is another environmental concern. Cyanide is a well known poison. Hydrogen cyanide is acutely toxic to humans and, in its gaseous state, can be fatal at exposure levels of 100 to 300 parts per million (ppm). Cyanide is likewise harmful to wildlife. Mammals, birds, and fish all have acute toxicity reactions to very low cyanide exposures. Cyanide does not, however, accumulate or bio-magnify, so prolonged exposure to sub-toxic levels does not, in most cases, appear to pose health risks.

The most significant environmental risk from the cyanide solutions used in gold mining is the possible leaching into soil and groundwater of cyanide at toxic concentrations, or catastrophic cyanide spills that might inundate an ecosystem with toxic levels of cyanide. One accident occurred in 2000, at a gold mine in Baia Mare, Romania, when days of heavy rain, ice, and snow caused a breach in tailings dam (tailings are the cyanide-treated ore wastes, from which gold has been removed), resulting in the release of 100,000 cubic meters of cyanide-rich wastes into the surrounding watershed. Drinking water supplies were cut off for 2.5 million people. It is likely that all nearly all of the fish in the waters immediately affected were killed.

 

 

Uranium Mining: Environmental Aftermath in Canada

 

 In Saskatchewan's boreal forest there are 78 documented abandoned mines, all with varying environmental and public safety risks. All of them need remedial action and all this will be at public expense, because the companies that created the problem no longer exist, and the mining industry takes no responsibility for this problem.

Of the 78 abandoned mines, 73 pose some hazard to both public safety and the environment. The worst site, Gunnar Mine on Lake Athabasca, scored 28.5 out of 26 for environmental danger (bonus points were assessed for additional hazards).

 

A total of 61 abandoned mine sites pose a significant risk to the environment, including:

a. persistent ponding and discharge of contaminated liquid

b. acid generating potential from waste rock and tailings runoff water

c. high radioactivity levels in waste rock and tailings locations

d. hazardous scrap materials and mill wastes exposed

e. direct hazards to wildlife: radiation, toxic chemicals, habitat contamination

All of these sites are now a public liability and ongoing stabilization, monitoring and clean up will cost hundreds of millions of dollars in years to come