Аңдатпа
Underground coal mining at great depths is associated with increased rock pressure, floor heave, and gas hazards, which significantly complicate roadway stability. Traditional mechanical support systems (rock bolts, cable bolts, shotcrete, and wire mesh) often prove insufficient in soft and fractured strata. Over the past decade, polyurethane (PU) grouting and combined support systems have gained wide application as effective methods of reinforcement and sealing. This review, based on 25 Scopus-indexed publications (2015-2025) and practical experience in the CIS coal basins, analyzes the properties of PU grouting materials, their injection technology, and their effect on roadway stability and gas drainage. Special attention is given to the role of thin spray-on liners (TSL) and hybrid solutions, as well as numerical modeling approaches (FLAC3D, RS2). The review highlights advantages of PU grouting such as high penetration and rapid strength gain, while also noting limitations including exothermic reaction, cost, and environmental concerns. A synthesis of international research and industrial trials in Kazakhstan (Karaganda Coal Basin), Russia (Kuzbass), and Poland demonstrates the efficiency of combined systems in controlling floor heave and stabilizing roadway surroundings. Research gaps are identified in the fields of low-exotherm formulations, multi-physics modeling, joint design of support and gas drainage, and standardization of monitoring protocols.