Tamponage of massif by modern polymeric materials for isolating mined-out areas in the coal seams prone to spontaneous ignition

Abstract

The causes of endogenous fires and methods to prevent coal spontaneous ignition were analyzed. Rational parameters of rock massif tamponage with different polymeric chemical compositions for stabilization of its stress-strain state and isolation of mine workings from methane penetration and fresh air leakage were investigated by the mine experimental methods. The dependences of the nominal pressure of injection of the chemical composition into the rock massif were established with taking into account coefficients of influence of rock type and stress concentration in the zones unloaded from rock pressure, in zones of geostatic pressure and in stress concentration zones. In order to control any accidental leaks of chemical composition through the main cracks, the stress-strain state of the rock massif in the mined area is taken into account for calculating the volume of substance to be injected. The parameters of methods for the rock massif cementation and tarring around the isolating bulkhead are substantiated. The method is developed for constructing a double isolating bulkhead in difficult mining and geological conditions to isolate the mined-out areas in the coal seams prone to spontaneous ignition.

Mitigating Coal Spontaneous Combustion Risk within Goaf of Gob-Side Entry Retaining by Roof Cutting: Investigation of Air Leakage Characteristics and Effective Plugging Techniques

“…On the surface of a coal mine roadway, sprayed concrete or mortar is usually used to plug the air leakage, but, due to the lack of toughness of cement mortar after curing, the roadway is easily prone to cracks and falls away when it is deformed under pressure, thus losing the role of plugging the air leakage. To solve the problems existing in the process of plugging the roadway by traditional concrete spraying, after much market research, a two-component composite modified polyurethane roadway spraying and plugging material is found to be able to quickly and effectively seal the air leakage channels existing on the roadway surface of underground coal and rock bodies [41][42][43][44][45].…”

Management of the longwall face advance on the stress-strain state of rock mass

“…Hence, loads increase and develop the reference pressure areas. Loads over the mined-out area decrease and develop a low pressure zone [45]- [47]. Abnormal pressure zones initiate in the neighbourhood of mining area with the increased loads above the rock mass and the decreased loads over the mined-out area along with the longwall face advance which results in the deceleration of mining operations [48]- [50].…”