Szkoła Eksploatacji Podziemnej

An important task of the efficient functioning of modern high-performance coal mines is to ensure the operational state of extraction workings. The increased depth of mining leads to an increase in the intensity of rock pressure manifestations in the rock mass, especially in the fundamental elements of the mining system, such as the junctions of longwall faces with extraction workings. Fractured rocks at the junction of the longwall face with the drift do not always retain their continuity and there is a danger of their falling out into the extraction workings, which leads to a decrease in the production level due to the inability to perform final operations and injuries to workers. This is especially important for the largest coal-mining enterprise, PJSC Mine Administration “Pokrovske” (Ukraine), which mines super-valuable coking coal in difficult conditions and where the specified geomechanical problems occur. The technological peculiarities of using known methods for rock mass strengthening to achieve accident-free maintenance of extraction workings in specific conditions of rock pressure manifestation have been analyzed. Various existing methods of fixing fractured rocks have been studied and systematized, followed by a comparison of the conditions for their use, advantages and disadvantages. It has been determined that a promising and effective measure that can significantly increase the stability of extraction workings is the use of injection strengthening of the rock mass with chemical resins for the purpose of bonding and maintaining continuity. The implementation of the injection rock fixing technology for accident-free operation of junctions of longwall faces with extraction workings requires a complex of laboratory and numerical experiments to determine the following technological parameters: rational distance of fixing the fractured mass in the extraction drift depending on the stoping face line according to the data analysis of the strengthened mass SSS curves; the sequence of performing technological operations for strengthening the fractured mass; rational volumes and type of fixing resins; the number of injection roof bolts and the distance between the roof bolts; the necessary devices and equipment for injection rock fixing and aspects of improving the extraction drift fastening system.