Analysis of forecasted methane concentration at the top gate of a wall ventilated by means of the “U” system. Case study

The release of methane into the mine atmosphere poses a threat to the miners. Methane is an explosive gas at concentrations of 5-15% in air by volume and throughout the history of coal mining has been the cause of devastating explosions in mines around the world. For these reasons, in methane coal mines, the concentration of methane emitted from the coal face and the entire mine is controlled by means of a well-designed ventilation system, a system controlling the concentration of methane in the mine atmosphere and a system for methane drainage of the rock mass and goafs. The presented article concerns the forecast of the average concentration of methane on a given day, in the places of sensors located in the longwall roadways of discharge air exhausted from the longwall: up to 10 m in front of the wall and at the outlet of the roadway. Both forecasts were made using the prognostic equations on the basis of measurement data concerning the ventilation roadways of one of the longwalls at JSW SA.