Determination of a potential set of factors which influence the situation of methane emission into roadways being driven

The currently applied methodology of absolute gassiness forecasting in roadways being driven in Polish hard coal mines is based on the results of investigations from before more than twenty years. At present the roadways are being driven in majority of cases in quite different conditions than those which had been the subject of the said investigations. The application of “old” methods of forecasting of methane emission during driving of roadways often brings about great discrepancies between the results of the forecasts and actual situation. It is firstly necessary to determine a potential set of factors which exert an influence on situation regarding methane emission into roadways being driven in order to prepare a verified mathematical model of absolute gassiness forecasting. On the basis of available literature and the investigations conducted by the Central Mining Institute an initial list of factors has been prepared which can have an impact upon methane emission into roadways being driven. The assumptions of heuristic method have been taken advantage of for selection of parameters and indices describing the phenomenon of methane emission. It has been dictated by the fact that the available literature is lacking a pretty unambiguous viewpoint on the subject under consideration and at the same time it is necessary to perform an a priori assessment of the information contained in a given feature (factor). A prepared initial set has been scrutinized to be verified on the basis of a conducted expert survey among seventy specialists in this field. After collecting of the results of the survey their statistical elaboration was prepared. The co-efficient of agreement of multiple ordering, the so called concordance co-efficient has been taken advantage of in order to check the competency of experts. The investigations prove that the experts are in agreement in their opinions. The estimation of a collective assessment of all participants of the survey was conducted with the use of the rank sum’s test by J. Greń. The results of the conducted analysis allowed determining a potential set of factors which influence the situation of methane emission into roadways being driven. This set, after conductance of further detailed investigations, can constitute a base for elaboration of a function describing methane emission into roadways being driven in hard coal mines.