Gold Mining in the Amazon

The Amazon of Peru is an enormous reserve of precious metals and fossil fuels. Rare and valuable resources, combined with policies advocating foreign investment and resource extraction, have left the region vulnerable to deforestation and degradation.

The country is the sixth largest producer of gold in the world, and the Madre de Dios forest is the second largest gold-producing region in the country (Burns, 2011). The modern gold rush has brought 10-30,000 illegal miners to Peru, motivated by the prospect of element, worth over $1,150/oz on the world market (Morante, 2010; BBC, 2009).

Gold extraction in the Peruvian Amazon is destructive and unsustainable. The most common method of extraction is sluicing, which manipulates fast-moving streams that carry sand, silt, and gold particles in suspension. Miners use a sluice box to extract gold from placer deposits. Sluice boxes create a straight, narrow channel with “regularly spaced slow spots created by riffles…The gold drops out of suspension as the water slows on the back side of the riffles” (Black Cat Mining, 2007). Mercury is added to the silt, used because its “high specific gravity [causes] it to lie safely under a stream of water and gravel, floating off on its surface everything and its relatively low boiling point which allow it to be driven off by heat from the gold with which it was amalgamated” (Gold Metallurgy, 2011).

While sluicing provides a cheap and viable option for gold miners, a great deal of mercury is used and wasted in the vicinity of mining activities. For every gram of gold extracted, five grams of mercury are used and typically deposited on the forest floor or in rivers (Clark, 2010). “Environmental organizations estimate that more than 40 tons of [toxic mercury] are dumped every year in the region, polluting rivers to the point that the fish are now inedible and can be sourced only from small fish farms” (The Guardian, 2011).

Mercury contamination has become a threat to groundwater quality, aquatic flora, and rain forest animals. Sluicing results in large, mercury-contaminated water pits, covering up to 18,000 hectares of land (Burns, 2011). According to Morante (2010), 32,000 tons of mercury enter groundwater sources annually, and water pits near mining sites contain mercury levels over three times the legal limit (Burns, 2011). Mercury-laden runoff that does not remain in water pits enters rivers, which has led to destruction of agriculture, fish stocks, and degraded drinking water (Morante, 2010).