Experimental study of transient thermal conditions in longwall faces

With limited mineral resources, existing mines are seeking to extract increasingly hard-to-reach and deep-seated mineral reserves. Increasing mining depth leads to problems connected with the provision of comfortable and safe working conditions. The main objective of creating favorable microclimate for miners is to provide acceptable values of air temperature in working areas at deep levels. Of particular interest are processes of formation of thermal conditions in longwall faces (longwalls), where high-performance hauling and mining equipment is used. We conducted a study to determine the formation of the thermal conditions in longwall faces. The study was based on experimental data obtained in the conditions of longwall face No. 1 of the first northern panel at the -440 m level of 4 RU mine of JSC “Belaruskali”. The findings of the experimental study of the dynamic microclimatic air parameters allowed us to establish that the thermal conditions in longwall faces were variable. This is due to the fact that during mining operations in longwall faces, the mining process cycle includes mining and maintenance shifts, characterized by different levels of heat release. The influence of thermal inertia of the equipment during shutdown for the maintenance shift plays an important role in the formation of thermal conditions. The findings of the experimental study of transient thermal modes in a longwall face during transition from mining shifts to maintenance shifts will form a basis for developing a mathematical model to calculate the heat exchange processes in mine workings (longwall faces). These will take into account the non-stationary nature of the technogenic heat release sources. The mathematical model will allow the safest and most effective technical and economic process solutions to be implemented, in order to control longwall face ventilation.