A.V. Shadrin, Dr. Sci. (Eng.), Lead Researcher, avsh-357@mail.ru FGBNU FITS UUKH SO RAN, Kemerovo, Russia
Effect of the speed of conducting mine workings for outburst hazard of the face space is analyzed in this paper. It is substantiated that the outburst hazard is determined by the combination of factors, the main of which are: stressed condition of the rock massif, gas factor conditioned by gas content and the pore pressure, coal strength and the rate of conducting working. The conditions of forecasting by instrumental and geophysical methods are considered. Instrumental methods are based on the analysis of the outburst hazard main factors on the basis of the results of the intermittent drilling of the control drill holes. They are rather long, and, therefore, difficult for integration into the technological process. To eliminate this shortcoming the geophysical prediction methods are used, in which the controlled parameter is associated with one or another main factor of the outburst hazard. Moreover, the hazard criterion of the geophysical methods should be «adjusted» according to the instrumental method, which is used as a reference method. However, the instrumental methods are performed in the put to stand face when the stresses are partially relaxed, and the geophysical ones — in moving. Therefore, the notion of static (in a put to stand face), and the dynamic (in the process of conducting working) of the outburst hazard is introduced. The structure of the dynamic factor of the outburst hazard in the form of the product of the static component on the dynamic effect function is substantiated in the article. Besides, the static component is presented in the form of the sum of two additives: the first considers the gas factor the gas factor, the second — the stress state factor. This structure is conditioned by the fact that the energy of sudden outburst is composed of the accumulated energy of the seam elastic compression and the energy of gas contained in it under pressure. It is substantiated that the function of the dynamic effect on the index and the criterion of outburst hazard is taken as a function of the rate of conducting the preparatory working, and for the room — as a function of the depth ratio of the combine pass to the length of the unloading zone. The methods are described for determining the coefficients in the formula for identification of the dynamic effect function from the results of measuring the lateral rock convergence dependencies, deformation of coal, and the increment of stresses in the coal seam on the speed of moving the working face.
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