Showing posts from March, 2011

Silver Causes Huge Increase in Mercury Use in Artisanal Gold Mining

Although gold is the primary target of most Artisanal and Small-scale Gold Miners (ASGM) that use mercury, the role of silver on mercury use can be astonishing. When mercury is applied to ores that contain both gold and native silver, in order to get all the gold, enough mercury must be used to amalgamate both the gold and the silver. Because silver is less rare than gold, some ores can contain ten times as much silver as gold or more - silver to gold ratios of 10:1 or 20:1. So more mercury must be added to these ores to capture all the gold. However, because silver forms a weaker amalgam than gold, the situation is even worse than these numbers imply. A typical mercury-gold amalgam formed by small scale miners contains roughly 50% mercury and 50% gold. Mercury-silver amalgam formed under similar conditions however is closer to 70% mercury and 30% silver. In the case of an ore that contains 10 times more silver than gold, about 20 times more mercury is added in order to capture the gol