Polymer resins are used for ground reinforcement in coal mines. This is made necessary by the fracturing of the rock caused by the great depth of the mines, and the consequent problems of roof support. In France, following a number of incidents resulting from the use of polyurethane resins, these materials have been replaced by phenolic resins for ground reinforcement. INERIS has earned out a study of the process used in the mines for injecting phenolic resins. From the preliminary risk analysis conducted by INERIS on the entire process of injecting these phenolic resins - from the arrival of the reagents at the pithead through to their use underground - it appears that the risks involved hi using phenolic resins are concentrated essentially in the polymerisation phase. It appears from laboratory tests that the increase in temperature that accompanies the polymerisation of phenolic resins is appreciably less than that observed when polyurethane resins are used in comparable conditions. Tests were carried out on greater quantities in order to characterise the risk that coal in contact with the phenolic resins during polymerisation would self-ignite. No coal ignition was observed in any of the tests carried out.