To prevent spontaneous combustion, the following comprehensive prevention and control measures are generally taken: 1. Because coal produces CO in the low-temperature oxidation stage, CO is a sensitive index of early exposure to fire.
CO sensors are set at the natural ignition places such as the return air pipe of the coal face, the upper corner and the fully mechanized mining roadway.
If the CO concentration exceeds the limit, it can be tracked and monitored using a portable CO detector to determine the high temperature point.
2. The infrared detection method is used to determine the position of the high temperature point.
The basic principle of infrared detection method is to establish the corresponding relationship between fire source and temperature field of fire source according to infrared radiation field theory, so as to infer the location of fire source.
3. Drilling temperature measurement is used for auxiliary monitoring.
Where the top coal is broken or there is a danger of spontaneous combustion, temperature probes should be embedded to monitor temperature changes regularly.
4. Strengthen air leakage detection.
For areas with uncertain air leakage channels, the tracer gas method can be used to check the air leakage along the gaps.
Strengthen observation in areas where air leakage is concentrated.
1, even pressure through risk control system air leakage and oxygen supply.
Equalized pressure ventilation is an effective measure to control air leakage in coal seam mining goaf.
First of all, regional pressure equalized ventilation should be fully implemented under the requirements of diluting CH4, wind speed, temperature and per capita air volume.
Pressure regulation measures include single pressure regulation and multi – measure combined pressure regulation.
The working face pressure equalization formed in the concrete implementation should be gradually expanded to the area pressure equalization of the adjacent goaf of the working face.
2, grouting plugging drilling grouting.
Fully enclosed shotcrete and shallow tight hole grouting are two effective measures to prevent natural fire in suspicious parts or hidden dangers in coal seam mining.
3. Gel injection for fire prevention.
It is a key measure to prevent and extinguish coal seam mining fire by using gel technology to deal with high temperature point or spontaneous combustion.
In this method, gelatin is injected into the surrounding coal at the high temperature point or ignition point, which can not only block the air leakage channel, but also absorb heat and reduce temperature.