Mercury use in small scale gold mining in Ghana: an assessment of its impact on miners
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Date
2002-12-12
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Abstract
Small scale gold mining is responsible for about 5% of Ghana’s annual gold production. It is estimated that between 80,000 and 100,000 people are engaged in small scale gold mining either on part-time or permanent basis. Amalgamation is the preferred method used by small scale gold miners for extracting free gold from its ores. The rate at which mercury, an important input in this method, is discharged into the atmosphere and water bodies is alarming.
This research describes the various mining and processing methods in small scale gold mining and the extent of mercury use and releases to the environment. It discusses mercury and its human and environmental effects. It defines the various forms of mercury, routes of exposure, toxic effects. The levels of exposure to mercury by all groups of small scale gold miners are determined, and the impacts on the miners and the environment are assessed.
It concludes that:
• Mercury is mainly released into the environment as a result of small scale gold mining through spillage of elemental mercury and evaporation of mercury from the amalgam and sponge gold when they are heated on open fire.
• Mercury in environmental samples from small scale gold mining areas is well above standard limit values.
• Mercury released into the environment through small scale gold mining impacts negatively on the miners themselves and the general environment.
Finally, it recommends the need for the adoption of mercury emission reduction strategies for dealing with the mercury problem.
Description
A thesis submitted to the Department of Mining Engineering,
Kwame Nkrumah University of Science and Technology in partial
fulfilment of the requirements for the award of Master of Philosophy in Mining Engineering, 2002