Optimization of geological and economic-geological evaluation of Dzhamgyr mining project

The vein gold–quartz deposit of Dzhamgyr contains 23 identified ore bodies, which are localized and controlled in the system of interconnected faults. The fault system forms six consistent spatial positional elements. Gold–silver mineralization is observed in all of the veins. The six ore bodies proved in detail are considered as the basis for forecasting and appraisal of vein deposit mineralization. Based on the results of studying the density and shape of the exploration network, the appraisal is carried out based on the influence of the sections of the mining level on the extended contours of the reserves. The morphological structure of the ore bodies and enclosing veins as well as the separation of broken ore enable the use of efficient and low-cost mechanized stoping systems. Integration of geological exploration and actual mining enables significantly improved efficiency of appraisal and preparation of mineral resources for extraction. Optimized geological and economic-geological evaluation of a mining project allows productivity increase, cost reduction and long-term planning of mining and investments.

Technological measures to enhance efficiency of mining ore from stopes applying self-propelled equipment

The work analyzes current technologies of ore mining applying self-propelled equipment in underground conditions; studies practices of using the equipment in general and for broken ore transportation only; considers performance of mining enterprises in similar mining-geological and miningtechnical conditions; analyzes and generalizes causes of high ore loss and dilution rates in underground mining in Kryvyi Rih iron ore basin, thus revealing a problem of providing high efficiency and increased ore extraction with minimal quality deterioration. Marketable ore production is affected by decreased quality and high broken ore losses. Incomplete balance ore extraction when breaking and drawing ore from the stope results in deterioration of mining indices. Ore dilution with waste rocks leads to decreased ore content in the mined mass as compared with that in the ore massif. The research enables development and substantiation of the rational technology of ore drawing and transportation as well as designing a new structure of the loading face to ensure increase of the drawn ore quality indices.

Influence of the parameters of the layer of ore being brought down on its freezing and losses during the face ore draw

Application of mining systems with ore caving and adjacent strata, which do not entail high expenditures on delivery of freed ore and rock pressure management, allows to considerably increase efficiency of underground mining of ore deposits in the cryolithic zone. However, their use where permafrost formations are prevalent, requires taking into account factors complicating mining operations, in particular, the congealing of broken ore in the stoping zone. In order to assess the impact of thermal and humidity conditions on the completeness of reserves recovery, a study was carried out to determine the dependence between the volume of losses of broken ore prone to congealing and the width and height of the layer being brought down. Experimental studies were conducted by physical simulation in a cryo chamber on a laboratory bench. The ore drawing was conducted in a uniform sequence at the temperature in the stoping zone of minus 5 ˚C. The final parameter to be determined the loss of ore prone to congealing, was defined as the difference between the mass of ore in the block and the mass of ore drawn. It has been established that the losses of the broken ore due to congealing increase significantly when the depth of the layer being freed decreases and the width increases. The established patterns of influence of parameters of a beaten layer on losses of ore mass will be used during development of recommendations on technology of drawing of ore mass prone to congealing in the negative thermal conditions of underground mines of a cryolithic zone.

Muck drawing by inclined two-dimensional flow

The work aims at studying and developing an efficient option of layer-by-layer muck drawing from the “dead area” of the footwall for the account of forming an inclined limiting contact of the muck ore with the unmined ore massif. The paper presents a detailed technical and economic analysis of factors and conditions impacting efficiency of muck drawing from the footwall “dead area”. The conducted studies of muck drawing on laboratory models considering a modeling scale enable determining optimal parameters of the layer-by-layer ore breaking and, further on, conduct a layer-by-layer muck drawing from the footwall “dead area” with minimum losses and dilution. The article determines regulations of the broken ore layer width considering possible obtaining of maximum muck values. On the basis of the conducted studies there are suggested optimal options of the technology of layer-by-layer breaking and drawing of the muck when forming an inclined limiting contact of the muck ore with the breakage face. The article proves practicability of breaking by inclined layers with formation of a limiting contact of the muck ore with the breakage face and suggests implementation of layer-by-layer muck drawing by an inclined flow.