A N2-charging/O2 controlling method to prevent subsurface coal mine gas accidents consists of: installing 2 hermetic separating doors in a mine at a >20m interval to form an isolated compartment capable of isolating a gas-containing mine space from O2 in an external air roadway; mounting a gas monitor system to determine the N2 concentration in the isolated compartment and the O2 concentration in a mine space entry, establishing a mixed gas circulating flow guide in the mining space, measuring the mixed gas O2 concentration using the gas monitoring system, transmitting early warning signals if the O2 concentration is >5%, and automatically cutting off the over-run region power supply when the O2 concentration is not <8%; installing a N2-charging and gas drainage pipeline systems in the mining space to replace the over-run region gas and control the mining space O2 concentration within a safe range; and installing an automatic temperature regulator inside the isolated compartment to regulate the temperature difference between the isolated compartment and the external air roadway at <5°, and prevent external air entry. The method also: ensures that workers entering the isolated compartment and mining space are wearing an O2 respirator; it established a ground monitor centre comprised of a central station, a working host, a display and connection cable, a spare machine, a sub-station in the mining space, and arranges an O2 sensor; and installs a N2-charging pipeline with a N2 pipe 3-way automatic valve at the separating door to the mining space and a special gas drainage pipeline with a gas drainage pipe automatic valve at the separating door to the external space in the isolated compartment to replace the isolated compartment gas when the N2 concentration is <95%. This method effectively prevents gas accidents.
Author: Chen, Decheng. ;Full Source: Faming Zhuanli Shenqing CN 102,287,216 (Cl. E21F7/00), 21 Dec 2011, Appl. 10,203,866, 21 Jun 2010; 8pp. (China). ;