Stoyan V. Prevention of blind workings gas pollution of coal mines by means of providing fail-safety electricity supply of the systems of local ventilation

The thesis is devoted to the estimating relationships between hazardous factors as well as failure of electrical equipment and the functioning of the systems of blind workings local ventilation, in which basis methods and means of prevention of blind workings gas pollution and explosions are substantiated. A mathematic model of gas pollution has been developed, according to which decreasing of probability of blind workings gas pollution is achieved by separation of power supply of the local ventilation system from technological loads and using of selectivity of protection against leakage currents to earth. The methods proposed provide decreasing of probability of blind workings gas pollution no less than in 5 times. The idea of failure-free power supply of workings ventilation and explosion-protection has been developed, which allows to estimate the effectiveness of the methods proposed and to prove the decrease of failure-free functioning of ventilation more than in two times, and decreasing of explosion probability not less than in 1,4 times. The idea of providing failure-free ventilation has been substantiated, an upgraded mobile plant has been patented and manufactured in which separate power supply of ventilation system and technological cycle as well as protection device against leakage currents on earth with selectivity of shutdown of the damaged connection are presented, which decreases the probability of gas pollution of blind workings. The new edition of labour safety regulations 10.0-7.37-13 has been developed entitled "Regulations of power supply and using of electrical equipment in blind workings of gas-hazardous mines ventilated by local ventilation fan" in which the new schemes for failure-free power supply are presented. Key-words: methane, gas pollution, event rate, hazardous condition, selectivity of short circuit protection, sources of current, continuity of fans power supply.