Exploitation of coal bed methane (CBM) is considered to be a method of extracting gas from non-conventional sources. The state of identification of CBM resources is shown in Table 12.1. Proven initial resources occur in 44 deposits in the Upper Silesian Coal Basin (Gornoslaskie Zagłebie Weglowe (GZW)). In the area of exploited coal deposits, the reserves extractable by methods of demethanization of mines are regarded as proven initial ones. In the remaining coal basins, i.e. the Lower Silesian Coal Basin (Dolnoslaskie Zagłebie Weglowe (DZW)) and Lublin Coal Basin (Lubelskie Zaglebie Weglowe (LZW)) ones no fields of CBM reserves have been proved. As regards fields of CBM being outside the exploited coal deposits, the resources possible for recovering are not defined because the quantity of recoverable methane will depended on the method of exploitation. Therefore, we decided to present in the tables the resources separately for both kinds of areas. All we can say is that approximately only one-third of CBM resources occurring in the areas being outside the exploited coal deposits is comparable with the initial proven resources of CBM in the coal mines. The methane output from the fields of proven initial resources amounted to 266 million m3 in 2004. The quantity of methane, called emission from ventilation system, emitted in 2004 to the atmosphere from the above-mentioned coal deposits amounted to 149 million m3 and decreased by 45 million m3 comparing to 1999. These data can be useful for estimating atmospheric pollution by methane from mine ventilation. However, for full estimation of, the atmospheric pollution also the mines in which methane was detected but the reserves of the gas have not been proved should be taken into consideration. Table 12.1 Coal bed methane (million m3)
* in the Budryk and Szczyglowice deposits the raw material occurs within and outside the area of actual coal exploitation and in the Ledziny deposit the raw material occurs in the zone accessible for coal mining (maximum depth of 1,000 meters) and in the zone of the depth between 1,000-1,600 meters as the main mineral raw material
The highest potential of CBM is found in the Upper Silesian Coal where perspective resources were estimated at about 350 billion m3 in 1991. The perspectives are considerably worse in the Lower Silesian Coal Basin where the perspective resources amounted to about 5 billion m3. In the Lublin Coal Basin, the possibility of CBM occurring is not excluded, but insufficient information does not allow quantitative estimation. Estimation of the possibility of methane occurrence relates to the zones with increased methane content defined by the limit of 3rd class of methane hazard (over 4.5 m3 per ton of crude coal matter (csw)). The zones pertain to the beds of thickness exceeding 0.3 m lying at a depth 1,600 m in the Upper Silesian Coal Basin and of 1,000 m in the Lower Silesian Coal Basin.
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