ANALIZA KSZTAŁTOWANIA SIĘ WYDAJNOŚCI OTWORÓW DRENAŻOWYCH METANU ZE ŚCIAN EKSPLOATACYJNYCH WĘGLA KAMIENNEGO JAKO ŹRÓDŁA ENERGII– STUDIUM PRZYPADKU

In hard coal methane mines, it is often necessary to use demethanation, in order to maintain methane concentration not exceeding 2% in the ventilation air. The basic method of methane drainage in the wall areas is through drainage holes made in the roof rocks of the deck, from the over-wall galleries, in front of the walls. Drainage holes are usually made in bundles, fan-shaped, with several holes in the bundle. The article presents the results of measurements and performance tests of one bundle of four drainage holes, made about 100 m in front of the face of the longwall. The evolution of the efficiency of individual openings over time and depending on the distance between the openings and the face of the wall was analyzed. High variability of the air-methane mixture intake through individual drainage holes was found, as well as large differences in the formation of the efficiency of individual drainage holes during the wall mining process. The use of this method increases the amount of captured methane for energy production and thus reduces operating costs.