INFLUENCE OF VARIOUS LONGWALL FACE VENTILATION REGIMES ON SPONTANEOUS MINE FIRE OCCURENCES AND INCREASED GAS RELEASE IN „RASPOTOČJE“ MINE OF ZENICA BROWN COAL MINES

Abstract

Brown coal mining conducted at greater depths, characterised with severe mining-geological conditions often results in deviation from the applied mining methods. Experiences gained in mechanised longwall mining of roof plate in deeper parts of Raspotočje mine, using method of roof caving without safety pillars left behind the working panels indicates to shortcomings of the applying mining method. Frequent occurences of spontaneous mine fires, of hazardous gasses well above the limit values, and constant exposure to rock bursts of various in- tensity resulted in application of three longwall face ventilation regimes: conventional „U“ ventilation system, ventilation with gas channel and middle hallway, and separate ventilation of the upper part of the longwall face. This paper presents experience based information gained in a five years period of mining, analysed using one- factor and two factor regression analyses applied to a number of technical-technological parameters (ventilation, mining system, etc) influencing occurences of spontaneous mine fires and increased gas release in various ventilation regimes at longwall face aimed to give basic guidelines for minimisation and elimination of certain hazards. Keywords: ventilation regime, spontaneous fires, gas release, mechanised longwall.