EXPERIMENTAL STUDY OF THE QUALITY OF ORE CRUSHING FOR UNDERGROUND LEACHING

The relevance of the study is caused by the need to find new ways to increase the production of metals. The volumes of substandard ores in terms of metal content of new and under construction man-made deposits can be involved in production with increase in the wastelessness of subsoil development. The aim of the research is to improve the quality of explosive crushing of ores for underground leaching of metals by experimentally substantiating the parameters of separation from the massif and crushing of metal ores. Object: ore-bearing massif and technological processes of breaking and crushing of ores of a particular deposit during a full-scale experiment in a pilot block. Methodology: critical analysis of the theory and practice of breaking and crushing ores for leaching in the store, organization of monitoring of the leached massif during the extraction of metals, modeling and interpretation of research results. Results. The paper introduces a brief reference on the history of the issue and describes the technique of carrying out an industrial experiment at a deposit of exposed ores. The authors have systematized the indicators of explosive breaking of ores in their shoring and proposed a criterion of ore crushing by explosion. The mathematical processing of the results of ore blasting was carried out. It was shown that the leaching method, even with a recovery factor of 70 %, does not compete with traditional technologies due to the loss of a useful component and requires improvement. The regularities of useful component distribution in the classes of chipped ore, described by the logarithmic-normal Gauss law, were established. It is shown that the size of the piece, which corresponds to the arithmetic mean of the content of the useful component, objectively characterizes the quality of the ore chipped for underground leaching. The difference between the proposed method and the traditional calculation of the weighted average linear size, which does not take into account the uneven distribution of metal between fractions, is formulated. The authors proposed the generalized model of explosive preparation of ores for leaching. The study of the useful component content distribution in the chipped ore, depending on the material composition, the nature of mineralization, the total metal content in the ore-bearing rocks, the technology of ore preparation can have a significant impact on the leaching indicators.