All-round Geophysical Forecast of Coal Seams Outburst Hazard


Annotation:

The outburst hazard index of the coal seam face space registered by the complex of geophysical methods that control the main factors contributing to the outburst hazard is substantiated in the article. It is shown that these are the formation pressure, in-situ gas pressure and the coal strength. Substantiation is based on the analysis of the known signs of the pre-outburst state of the roadhead. As such, the following two are selected. The first sign is the beginning of cracks development in the roadhead space under the influence of the rock pressure and gas in-situ pressure, which leads to the creation of the block structure in front of the roadhead. The second sign is the beginning of pressing out of several blocks of coal at the opening of the outburst cavity. For this two-stage model of creating outburst hazard situation, the physical criteria are substantiated with regard to the beginning of each stage expressed in terms of the parameters of the rock massif characterizing the main factors of outburst hazard. The following complex of geophysical methods is substantiated for their control. To control the stressed state of the rock mass, the spectral-acoustic method has been proposed, which is based on the analysis of the spectrum of acoustic signal generated by the working mining equipment. To control the in-situ gas pressure it was proposed to use the gas-analytical method based on recording the concentration of methane at the roadhead by gas control equipment. It has been proposed to periodically define the coal strength by the strength gauge, which work is based on measuring the depth of penetrating steel cone into the coal by the spring mechanism.

The current outburst hazard forecast by the all-round geophysical method consists in estimating the stress state of the roadhead space by the spectral-acoustic method, critical value of which is continuously corrected by the data of the gas analysis method and periodic strength readings of the most broken ply.

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DOI: 10.24000/0409-2961-2019-1-42-48
Year: 2019
Issue num: January
Keywords : outburst hazard influencing factors stability loss model forecast method signal spectral analysis
Authors:
  • Shadrin A.V.
    Shadrin A.V.
    Dr. Sci. (Eng.), Lead Researcher, avsh-357@mail.ru Coal Institute FITs UUKh SO RAN, Kemerovo, Russia