ICMGP - Conference Presentation

Abstract Information :

The process of mercury amalgamation is widely used in artisanal and small-scale gold mining. With the ability to form metallic alloys with metals such as gold and silver, mercury amalgamation is used to separate metals of interest from sediments. The process has an efficiency of 25 to 35%, which is largely due to the mercury inability to amalgamate smaller gold particles. It is estimated that approximately 15 million people depend directly on it, especially South Am‚rica and African countries. The widespread use of mercury is one of the main causes of its emissions to the environment. Having a great environmental and human health risk, mercury can cause severe respiratory dysfunction and its contamination endangers the entire food chain. Replacing mercury is urgent and large-scale mining companies already do this, using methods as cyanidation. The major problem is the mercury use in artisanal and small-scale mining. In this sense, flotation and the use of plants (often native) with ?amalgamating? potential, such as balsa leaves (Ochroma pyramidale), bitter cassava (Manhiot esculenta) and bamboo shoots (Bambusoideae) have been tested. There is a huge potential in the use of cyanogenic plants, (plants that have cyanogenic glycosides, which when hydrolyzed release hydrocyanic acid), providing the ability to separate gold particles from sediments. In this regard, it is clear that several methods are presented for the replacement of mercury in gold mining. However, governmental and scientific efforts are necessary to make the use of these new means a reality. This research aimed concretely characterizing the efficiency and toxicity of these alternative methods testing samples of a legal gold small-scale miners cooperative in Brazil to encourage the regulations that favor the total abandonment of mercury and the use of methods with increasing efficiency and less environmental and human health impacts.