A heap cryoleaching technology for gold ores was justified basing on theoretical and experimental research into physical, hydrophysical and physiochemical properties of sulfuric-chloride solution in the presence of manganese dioxide within a wide range of negative temperatures. This geotechnology enables year-round heap leaching of gold in conditions of the permafrost zone through controlling concentration of the electrolyte-cryoprotective agent – sulphuric acid.
Widespread development of gold leaching in areas of permafrost soil demands geotechnology modernization. In particular, the paper studies enhancement of gold heap leaching geotechnologies with cryogenic gold ore disintegration. Such statement of the problem can become the first step in creation of modern mining cryotechnologies in conditions of sub-zero temperatures.
The paper presents results of cryogenetic impact on mineral composition and geotechnological properties of alluvial gold-bearing raw materials of natural and man-made origin. In particular, distinctive features in mineral composition of alluvial deposits are described within the permafrost zone and outside it as well as the nature, mechanisms and peculiar features in reduction of man-made gold amalgams are shown. The results obtained were used to justify the expediency of implementation of the combined heap gold ore leaching technology at alluvial deposits in the permafrost zone, which includes preliminary concentration of coarse, medium and fine gold as well as the gold amalgam.
Optimal parameters of geotechnology of stock pile formation from pelletized gold-bearing ores were established basing on experimental and theoretical studies in order to enhance its filtration properties. In particular, exponential dependence was established of permeability coefficient on the stock pile height and the ultimate strength of the pelletized ore, its bulk weight and content of coarse particles +2 mmin combination with sandy-loamy and loamy fine grained soil. Without account of this data loss of gold within the stock pile can increase over 2 or 3 times. Basing on the results obtained application of the combined geothechnology of heap leaching of gold-bearing clayey materials of natural and man-made origin was justified.
The paper presents the typology of forms of disturbance of natural conditions and types of technological objects used in the development of mineral deposits of the cryolithozone by open-cut mining. The reasons for the formation of talik zones (reservoirs) of technogenic-natural genesis, accumulating useful components, as well as harmful chemical elements, artificially introduced into the rock massif during the development of placer gold deposits in the cryolithozone conditions are considered.
