Low-pressure hydraulic impact on the coal massif and the purpose of its application

The purpose of the application of low-pressure hydraulic impact on the coal massif is discussed. A brief description of the coal structure is given – from molecules to large structures separated by endogenous and exogenous cracks. The fractured porous structure of the coal seam is described. Information on micropores, transitional and macropores, systems of exogenous cracks is given. The results of the performed studies indicate the possibility of blocking gas in coal pores with pumped water and preventing high pressure of free gas near the plane of seam exposure, which opens up the prospect of hydraulic action on the massif to prevent gas accumulation in the workings and sudden outbursts of coal and gas. It was established that the most effective mode of injecting water into the seam to achieve this goal is low-pressure water infusion, and its parameters were defined by experimental studies. The results of theoretical and experimental studies showed that with low-pressure water infusion, coal becomes less durable and elastic and more plastic. The coal massif adjacent to the mine or contoured by several mine workings loses the ability to brittle fracture, and the arising loads are largely realized in the form of plastic deformations that do not lead to rock bumps. (paper)