The success of the physico-chemical technologies’ application in the development of ore deposits, such as underground and heap leaching, depends on the petrographic and mineral composition of the ores and their host rocks, type of reagents leaching the useful component, technology of ore preparation and irrigation modes of lumpy ores. The efficiency of leaching of uranium-ore minerals is determined by the physico-chemical laws of the interaction of reagents with the ore material. In the course of the research, the relationship between the silica content in the rocks containing mineralization and their physical and mechanical properties was established. This makes it possible, knowing the type of rocks, to predict the conditions of ore preparation by drilling and blasting to obtain the optimal piece size for leaching. In addition, the influence of the ore texture on the leaching efficiency was proved experimentally. Previous researchers found that the rate of conversion of uranium to the mobile state during leaching depends on the rate of penetration of the leaching reagent into the piece, displayed by the effective diffusion coefficient (Kef). The analysis of mining and geological information made it possible to establish the relationship between the Kef and the type of host rocks through the SiO2 content and the type of uranium minerals through the uranium content. The obtained knowledge makes it possible to predict favorable conditions for the use of physico-chemical geotechnologies in the development of rock-poor uranium deposits
The widespread introduction of physical and chemical geotechnologies in the production of mineral raw materials makes it possible to involve ores that are poor in the content of the useful component, which are unprofitable to work out using traditional physical and technical methods. One of these new geotechnologies is the heap leaching of rocky uranium ores. When planning the volume of output of finished products, it is necessary to have an analytical apparatus that would make it possible, using the acquired knowledge, to calculate the required volume of mineral raw material production and its varietal composition. Based on their task, studies were conducted on the qualitative and quantitative characteristics of ores that affect the indicators of extraction of useful components from them. As a result of the research, the dependence of the index of uranium extraction into a productive solution during infiltration of sulfuric acid leaching on the material composition of ores was established. Ores localized in various lithological differences of acidic, medium and basic rocks were tested: granites, felsites, trachydacites, andesites and conglomerates. The ores were classified according to the size of the piece with the allocation of fineness classes +200 mm, -200 +150 mm, -150 + 100 mm, -100+70 mm, -70+ 30 mm, -30 mm. The tests were carried out in laboratory and semi-industrial conditions. The maximum extraction was obtained for the class – 30 mm in columns. When leaching in stacks, the maximum extraction of uranium into the solution was obtained for the size class -70+30 mm. The reason for the lower extraction from the -30 mm class during leaching in semi-industrial conditions was the processes of mechanical colmatation, due to the large number of fine fractions. The criterion characterizing the material composition of ores is the content of silica (SiO2). During the tests, the dependence of the uranium extraction coefficient in the productive solution on the content of silica in the ores was established. The higher the concentration of silica, the more uranium passes into the productive solution during leaching with a stable composition of uranium mineralization. The dependence is described by a mathematical formula, which allows us to use it to calculate the extraction of uranium into a productive solution, knowing the material composition of ores
PAO “Priargunsky Production Mining and Chemical Association” has been working on reserves of uranium deposits of the Streltsovsky ore field for more than 50 years. During this period, most of the rich ores have been worked out by traditional mining and physical technology. The share of poor and ordinary ores remains significant, but traditional technology does not provide the necessary level of profitability. Therefore, the widespread introduction of physicochemical technology: underground block (BPV) and heap leaching (KV) can be a decisive moment in the continuation of the operation of these deposits. The applied technology of underground block leaching has one significant drawback – a low rate of uranium recovery into a productive solution, which significantly reduces the effectiveness of this technology in the development of poor uranium deposits. To increase the yield of uranium into the productive solution, it is necessary to analyze the entire preparation and leaching process and establish the main reasons for the low rates of transition of uranium to a mobile state. For this purpose, it is proposed to simulate the underground leaching process by building visual models of halos spreading of solutions along shrinked ore mining mass accumulated in an underground chamber. During the simulation, it was found that the distribution of the size classes of the broken ore pieces in the chamber can be predicted at the stage of drilling and blasting operations, and when determining the line of least resistance W and the distance between the ends of the wells, take into account the diameter of the controlled crushing zone R_p. At the same time, 3 zones of granulometric compositions are formed: a re-grinding zone, an optimum zone and a non-carbarite exit zone. The flow of solutions through these zones will differ the more significantly, the higher the height of the chamber. In a zone with larger crushing, an almost steep distribution of the solution spreading front is expected. Accordingly, the smaller the fraction, the lower the front to the horizontal is. The following functions are offered to simulate filtering processes: – it is possible to control the flow of working solutions to the fan of irrigation wells in order to achieve optimal leaching parameters, i.e. to quickly control the process; – knowledge of the law of distribution of irrigation flares makes it possible to select the optimal grid of location of single sprinklers
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