A method for preventing methane explosions when mining gas-saturated coal seams

Purpose. The research is aimed at improving the methods for preventing coal dust-methane explosions during cutting-loading machine operation when mining coal seams with gas-dynamic phenomena (GDP). Methodology. When performing the research, basic methods of mathematical and physical modeling, bench experimentation, as well as methods for processing the results of laboratory and industrial studies in the EXCEL and MATHCAD environment were used. Measurement of the dynamic parameters of the cavitation flow of the liquid (frequency and range of pressure auto-oscillations) was carried out using the ДДІ-20 sensor. The signal through the AЦП-12 analog-to-digital converter was sent to the hardware and software complex based on the Athlon-800 PC with the “DASYLAB” and “GEMIS WIN” software. Findings. A method for combating explosions of dust-methane mixture has been developed. A generator of cavitation self-oscillations of the mine flushing fluid pressure is used to automatically destroy and remove clogging from the nozzle channels of the irrigation system. Simultaneously with the supply of the water-air mixture directly to the broken coal mass, the coal dust-methane mixture, formed in stagnant zones near the face, is sucked in by a perforated pipeline and sent through a non-perforated pipeline outside the cutting-loading machine boundaries in the direction of the mine working ventilation flow. Originality. The use of cavitation generators in the irrigation system of cutting-loading machines in the process of rock breaking to prevent coal dust-methane explosions has been scientifically substantiated. Functional dependence has been determined of amplitude and frequency of the flushing fluid self-oscillations periodically created at the outlet of the cavitation generator on the boost pressure, which periodically occurs as the nozzle channels are clogged with destruction products of mine water supply system and rocks. The automatic destruction and subsequent removal of clogging from the nozzle channels is performed by high-frequency self-oscillations of the flushing fluid, the pressure of which at maximum amplitude and frequency values exceeds the ultimate compressive strength of the debris particles. Practical value. The improved complex method can ensure uninterrupted operation of the irrigation system nozzles and significantly reduce the probability of the coal dust-methane mixture explosion in the places of broken gas-saturated coal accumulation during cutting-loading machine operation. It also increases the safety of mining operations when mining coal seams.