Sudden coal and gas outbursts in coal mines are one of the most harmful and at the same time, dangerous gas-dynamic phenomena faced when coal producting. The sudden coal and gas outbursts is the evanescent destruction of the bottom-hole area in the coal bed, which develops from the bottom into the depth of a massif, and the crushed coal with gas is thrown to a long distance from the bottom into the mine, destroying everything in its way, creating the conditions for explosion and fire breaking-out. Sudden outbursts lead to significant material losses for the recovery from an accident and in some cases injuries and human losses. The problem of reliable prediction, prevention, and control of sudden coal and gas outbursts at coal mines remains extremely urgent, due to the constant increase in the depth of mining operations. The analysis of the experience of predicting and preventing the outburst hazard in coal beds of Donets and Lviv-Volyn coal basins is analyzed. At Donbas mines since 1906, there have been more than 7.5 thousand sudden outbursts. Although mining had now reached considerable depths (from 300 to 600 m), the emergence of coal and gas outbursts have not been recorded. The purpose of the research is to determine the depth of the possible emergence of sudden coal and gas outbursts in the LVB, with regard to the peculiarities of the geological structure of the coal-bearing strata in the Lviv-Volyn coal basin. The comparative possible depth estimation in the manifestation of the outburst hazard of the coal beds in the LVB is given. It is calculated according to the normative technique and performed according to the formulas obtained by the statistical analysis for the actual position of the minimum depth of coal and gas outbursts at the Donbas mines. The absence of sudden coal and gas outbursts at LVB mines on the coal beds, which are hazardous according to the prediction data, is performed according to the methods regulated by the normative documents and compiled by the experience of studying the outbursts in Donbas, is explained by the differences in the geological structure of the LVB, the main of which is the presence of thick mass of covering deposits and a significantly greater depth of the methane gas zone. The application of the empirical formulas prediction, which includes the methane gas zone depth index, allows us to account for these differences and it is much more reliable to determine the possible depths of sudden outbursts for LVB, which, all other things being equal, should be greater than in the Donbas. In particular, according to the performed calculations, the outburst hazard situation at the “Stepova” mine is predicted at depths of more than 700 m. As prediction indices for the calculations, values of methane gas zone depths of 450 m were adopted, and the minimum value of volatile-matter yield was 33.3%. This approach can be proposed for predicting the coal and gas outbursts hazard in other Lviv-Volyn basin mines. To determine the predicted depth of the possible emergence of sudden coal and gas outbursts, it is advisable to take into account the depth of the methane gas zone in the prediction calculations.
Conditions for a start of sudden coal and gas outbursts in the breakage faces of coal mines
