Abstract
The results of laboratory and field investigations of a two-component polyurethane resin "Sika" for injection reinforcement of fractured rock masses in underground mine workings, are presented. The study addresses the need to improve roadway stability under complex stress-strain conditions, tectonic disturbances, and high moisture typical of the Karaganda Coal Basin. Laboratory tests evaluated curing time, reaction temperature, foaming coefficient, and crystallization duration, confirming stable and reproducible properties suitable for underground application. Field trials at the Kazakhstanskaya mine using IRMA-type anchors compared "Sika" with the conventional Bevedol-Bevedan resin. The results showed that "Sika" forms a strong monolithic structure, обеспечивает high adhesion to rock and metal supports, and reduces material consumption. Overall, the resin proved effective in strengthening weakened zones, decreasing stress concentration near excavation contours, and improving underground roadway stability under complex geological conditions