CRYSTAL-SAVING TECHNOLOGY OF OPEN MINING OF COMPLEX STRUCTURE KIMBERLITE DEPOSITS
Relevance and purpose of the study. Extraction of kimberlite ores should be carried out with the maximum preservation of the natural quality of mineral raw materials. The cost of crystals contained in the ore depends primarily on the size of individual diamonds and their defectiveness. It is possible to increase the safety of the extracted crystal raw materials by abandoning explosive loosening and switching to a mechanical method of ore extraction, including its preliminary physicochemical softening. At the same time, the greatest effect from such mechanical extraction is achieved when mining high-value ores. Currently, in connection with the development of mining equipment, a main part of the kimberlite massif can be mined using mechanical means of extraction of a cyclic or continuous action. Objective. The research is aimed at providing a scientific rationale for the improved crystal-saving technology of field development based on a flexible combination of technological processes of preparation for mining with the differentiation of kimberlite ores by a set of indicators, taking into account their value and strength parameters. Result. The paper proposes a technology for the development of complex structure diamond ore deposits with the use of selective preparation of kimberlites for excavation and the actual excavation. Initially, by drilling a network of wells and interval sampling of the mineral mass, sections of the ore massif are differentiated into zones, followed by local thickening of the network of wells in the zone of high-value ores. When individual intervals of ores of an anomalously high value are identified, they are extracted by drilling out a large diameter core with further processing of ores using improved methods. High-value ore zones are prepared for extraction by a mechanical method by softening due to the impregnation of the massif with an active liquid-gas mixture produced by electrochemical processing of the natural brine followed by the extraction of weakened ores with a single-bucket excavator. Zones of common value ores and a zone of ores of a low value and low strength are mined using a layer-by-layer milling machine, which makes it possible to obtain small lump or medium lump ore mass, followed by selective mining of loosened ore by loaders. The zone of ores of a low value and relatively high strength is prepared for extraction by means of blast-injection preparation using shaped charges of a special design. This zone is delineated by means of a buffer layer formed by drilling technological wells and impregnating the massif through them to reduce the negative effect of the explosion on adjacent ore zones. The exploded ore mass is removed from the heap by loaders.