Most coal mines in Chongqing Area are highly gassy mines and liable to outburst of coal cnd methane. In order to harness mine environment and raise the Prodction capacity, methane predrainage is generally taken as a main preventive measure against outburst by all mines. In the recent ten years, the drainage volume per year has increased from 38.25 million m3 to mote than 100 million m3 with a volume over 12 m3 per tome of coal. In some mines, the draining rate is approaching to 50 percent, the rate in mining districts is up to 60 to 70 percent. The predrainage volume accounts for one fourth of total drainage volume. All these have effectively prevented the occurrence of coal and methane outbursts._x000D_
This is the current situation of methane predrainage in coal mines in Chongqing area, the methods of predrainage to prevent outbursts and related parametres comprise: 1. methods, technologies, supervision and effect of predrainage in different geological and mining conditions, 2. the change of methane parametres pre-and post-drainage and the analysis of the effect of methane predrainage to prevent outbursts, and 3. ways to improve the effect of methane predrainage._x000D_
Thus the safety, reliability and production of Changqing Coal Mines will be enhanced.