Study On Disasters Resulted From The Leakage Of Wind And Technology Of Preventing And Extinguishing Fire In Top-coal Caving Of Steep Seam

Urumqi mining area has more than 30 seams with different thickness and spacing of the steep seams, which is a rare occurrence conditions in the world. Coal seams in the minefield have been affected by coal spontaneous combustion and duplicated burning in the old fire areas, which is a serious threat to safety. Production of coal mine. All coal mining methods are very backward before 1980s(1951～1987), the coal mine which has lower degree of mechanization level, poor safety and low rate of recovery has the danger of serious spontaneous combustion. As the reform of mining methods and development of modern caving technology after 1980s, condition of the working face was improved, but the using of top coal caving was still extremely constrained As development of efficient mining technology after 2004, the number of spontaneous combustion .declined sharply, but spontaneous combustion of coal seams still is the main reason for restricting the development of effective working.This paper is based on the actual situation of spontaneous combustion in Urumqi mining area. In summarizing the results of previous studies, site survey data, Summarizing fire-prevention experience, and through engineering statistical analysis and similar simulation, causes from the leakage of wind and characteristics of fire was deeply researched in Urumqi mining area. as well as the measures of controlling fire. The main conclusions reveals that spontaneous combustion is mainly focused in roof and that the oxygen passage is created from the surface to gob above working face. The oxygen passage would create coal spontaneous combustion in gob and enormous harm for safety production of working face. The occurrence of fire is not in the same coal seam, but in gob above working face because of high temperature and open flame. Stopping up air leakage passage supplying oxygen that shuts off coal spontaneous combustion is one of essential technical measures in safety production of coal mining.Aiming at characteristics of spontaneous combustion in Urumqi mining area, this paper presents a defense method suited to self characteristics and fire-prevention measures by means of backfilling soil, pressure balance and nitrogen injection. The conventional face pressure observation is converted to two roadway observation, and the conventional nitrogen injection by burying pipes is converted to injecting nitrogen by drilling holes in advance using innovation and development of the fire-prevention techniques and backfill in time based on the subside characters of steep seam at the scene. An effective fire-fighting technology eventually formed by using optimal combination of fire-prevention technology. This measure has great significance to development of modernization coal mine and safe production in Urumqi mining area.