Dissolution And Redistribution Mechanisms Of Gold Inside The Tailings (Mine Dumps) And Their Applied Significance
Naumov, Vladimir Aleksandrovich (1); Fiorucci, Adriano (2); Goldyrev, Valeriy Valerievich (1); Bryukhov, Vitaliy Nikolaevich (1)
1: Perm State University, Russian Federation; 2: Turin Politechnic University, Italy
In the entire history of mining, 180 thousand tons of gold were extracted from the depths (data from 2017), with an average gold grade of 2.2 gpt. Thus formed to 600 Bln. tonnes mine dumps, which provide variously estimated to ~ 40% of the unrecovered gold from initial rocks, with an average content of 0.2-0.5 gpt. As the natural deposits of gold are exhausted, there is an increasing interest in the processing of auriferous technogenic deposits. Gold-containing dumps, often already reclaimed, are processed by standard schemes in violation of the existing ecological balance.
The authors have studied the processes of release, transfer and accumulation of gold-bearing phases within the tailings and the role of technogenic waters in these processes. The objects of the research were polygons of the Urals, Siberia, Canada and Northern Italy. The conclusions about the formation of local areas of gold concentration in the process of technogenesis are made. Field and laboratory experiments on the accumulation of gold at various barriers were carried out.
Gold in the tailings is installed in different forms of finding. The authors studied in detail the solid phase of technogenic gold (free, bound in minerals, in intergrowths, "film" and sorbed on minerals). The presence of gold in solutions of technogenic waters has been established.
The following transformation processes of auriferous dumps are identified and studied: destruction of rocks and mineral phases; transportation of material and transport of chemical elements in dissolved form; accumulation and formation of new mineral and petrographic differences. The processes of transformation of tailings lead to the redistribution of gold and the formation of local zones of its accumulation.
Base role in these processes have aggressive technogenic water. A part of gold dissolves, is transferred and is further deposited on geochemical barriers inside the tailings. The authors have studied the following geochemical barriers on which gold is deposited: carbonate (for acidic waters); carbonaceous; electrochemical on metal bases (natural electrolysis).