Donlin Gold Project

Donlin Gold Project

Donlin Creek Exploration Roads Source: Northern Alaska Environmental Center (2003). Copyright held by photographer.

The Donlin Gold Project is a proposed gold mine in the Kuskokwim River watershed in southwest Alaska.  Donlin Gold LLC, which is owned by Barrick Gold Corp. and NOVAGOLD Resources Inc., filed a permit application for the mine in August, 2012, and the Environmental Impact Statement process began in December, 2012.  Donlin Gold estimates that the mine would produce roughly 34 million ounces of gold over 25 years.  There is widespread support for the mine among local communities due to its potential to create jobs in the region.  Donlin Gold would be an open-pit mine using cyanide vat leaching to extract gold.   The mine would require construction of tailings and waste rock storage facilities, an ore stockpile, a mill, and a support complex including an airstrip, river port, housing, and other facilities.  Due to its remote location, Donlin Gold proposes to construct a 313-mile, $834 million natural gas pipeline from Cook Inlet to power the mine.

There are several potential environmental and health concerns with the Donlin mine.  The mine has a high risk for mercury contamination.  The bedrock in the Donlin Creek area contains significant amounts of mercury, which is already present in the watershed due to abandoned mines in the area.  The Donlin mine would release mercury in the mining and milling processes.  The mining plan calls for mercury capture at multiple stages. This mercury will need to be transported off-site.  EPA guidelines allow mines to release 84 pounds of mercury for each million pounds of ore.  If Donlin processes 59,000 pounds of ore per day, then it could emit up to 1800 pounds of mercury into the air per year.  There is also the risk of residual mercury release and mercury release due to erosion of mercury-containing rocks placed in waste-rock piles.

Mercury is extremely toxic and can damage the human nervous system.  Children and fetuses are especially vulnerable because their nervous systems are still developing.  Bacteria can alter mercury that has entered the water into methylmercury, a chemical which enters the food chain.  Methylmercury can become concentrated in fish, posing a health hazard to people who eat those fish.

Acid mine drainage presents a second issue.  Much of the rock at the Donlin site contains iron sulfides.  When exposed to the environment, iron sulfides react with oxygen and water to  generate sulfuric acid.  This can enter the watershed, causing it to become highly acidic.  The feasibility study for the mine implies that active water treatment will need to continue forever to mitigate this acid.

Other pollution issues include release of cyanide from the cyanide vat leaching process and release of heavy metals such as arsenic, lead, antimony, and cadmium.

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