Prospects and problems of stack processing of waste dumps of gold-extraction plants

The long-lived waste dumps of gold-extraction plants, by the amount of gold concentrated in them, are an alternative source of raw materials for the gold-mining enterprises. During the long-term storage of waste dumps, difficult-to-extract gold under the effect of environmental factors is being opened up and can be extracted using the cyanide process. It is established by investigations that the extraction of Au during percolation cyanidation attains 75–82%, and waste dumps can be used for their heap leaching. However, because of a low fineness of mineral formations, percolation of working solutions through the stack bulk and its retention from static destruction are complicated. The technology of pelletizing the waste dumps with the use of predrying with warm air or by mixing with the ore in definite proportions is suggested. To prevent washing out, the stack height should be smaller than that with the use of the ore, and its edges should be protected by natural coatings. Therefore, processing of waste dumps by heap leaching can turn out to be a promising practical direction.