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Purpose. Research into the method of strengthening destroyed and fractured rock massif by micro-cement injection during rock driving at Orlovsky mine of "Vostoktsvetmet" LLP. Methods.In situ researches of massif strengthening by cement slurry were performed. Monitoring of injection works implementation was carried out by control tests of reinforced rock cores. Phase composition of core samples (crushed probe) was defined on the X-ray diffractometer. Method of raster electron microscopy with energy dispersive microanalysis was used to determine the surface morphology and local elemental analysis of core samples. The material and labor costs related to works on strengthening of rock massif were calculated.Findings. Massif strengthening method was studied. MasterRoc MP 650 micro-cement produced by BASF Construction Chemicals Ltd with addition of 1 -2% of cement weight of Rheobuild 2000PF was used as cement slurry. The uniformity of the working contour in tunnel faces was observed after the third cycle of works on rocks injection. Unsafe working conditions for packer installation have been revealed. It was recommended to carry out pilot tests of tunneling technology in destroyed and fractured massif using the two-component organic-mineral resin "Blocksil" and long selfwedging packers with injection tubes.Originality. We established peculiarities of implementing technology of strengthening destroyed and fractured rock massif by micro-cement injection. Quantitative indicators of micro-cement content in the injected rock massif were identified.Practical implications. Technology of strengthening destroyed and fractured rock massif by micro-cement injection was developed and tested at Orlovsky mine.

Purpose. Justification and selection of a rational scheme for accessing the second ore body of the Irtysh deposit based on a technical and economic comparison of its adopted competitive options.Methods. The main mining, geological and engineering requirements for selecting the scheme for accessing the Irtysh field are considered to achieve the goal. Three competitive accessing options are proposed on the basis of project regulatory documents and geotechnological features of the ore body. The optimal scheme of accessing was suggested taking into account the volumes of mining and preparatory works and averaging of the metal content in the ore by the method of technical and economic comparison.Findings. Analysis of the accessing schemes was performed for deposits similar in the geological conditions and represented by fragmented ore bodies. The advantages and disadvantages of 3 competitive access options are reviewed in detail. The technological and economic feasibility of excavation of ore body 2 reserves has been substantiated, i.e. of accessing them by fringedrifts between the Irtysh and Vspomogatel'naya mines on the upper horizons of the deposit. It is established that the difference in the volume of capital works (CW) and preparatory works (PW) is 45640 m 3 in favor of accessing ore body 2 by fringedrifts between the Irtysh and Vspomogatel'naya mines. At the same time, the volumes of CW and PW at the initial and final stages of development are much lower than in the case of accessing by a transport ramp from the surface. The change in the average content of copper, lead and zinc with the simultaneous development of the Osnovnaya Deposit and the South-Eastern Deposit in the lower horizons of the field has been calculated.Originality. For the conditions of ore body 2 of the Irtysh deposit, planned for development in accordance with the proposed access, it was found that despite the decrease in the copper content in the saleable ore, the lead content in the saleable ore will increase to 0.49% and zinc content, respectively, to 3.83%. Practical implications. Mining of ore body 2 according to the recommended accessing scheme with a minimum amount of mining will allow to raise the productivity of the Irtysh mine to 600 thousand tons per year during the period 2018 -2026, as well as to increase the extraction of lead and zinc.

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