Environmental Protection by Paste Production and Storage Mechanism for Cyanide Disposal in Gold Processing- A Case Study, Aq Dareh, Takab, Iran

摘要

Cyanide is widely used to process low grade ores such as gold and silver economically. However, its high levels of toxicity pose many environmental pollution problems that are major sources of concern for mining engineers and environmental groups. HCN and CN- are two major cyanide pollutants that threaten aquatic life and constitute health hazards for human beings and other creatures. In gold processing, the pH is kept above 10 in order to prevent the release of dangerous HCN gas. In Aq Dareh mine, the gold processing slurry that contains cyanide is transported to the tailings dam, and damages the aquatic ecosystem in downstream environments. This paper describes the paste production and storage mechanism (PPSM) as an alternative method for cyanide disposal and presents the results of the application of PPSM in Aq Dareh gold processing plant. Using the PPSM system, the solid residue paste containing high concentrations of toxic cyanide is dumped on the ground, but limits cyanide release into the surface and ground water system. The use of PPSM in Aq Dareh gold processing plant can considerably reduce pollution problems caused by the release of cyanide into the environment.