The basic requirement of roadway in a mine is to provide sufficient height and cross section consistent with adequate support to meet the needs of accomodation of equipment, transport, personnel travel and ventilation. However, many roadways are deformed to the extent of needing maintenance, generally dinting, and in some cases requiring re-ripping. The deformation of a roadway is a function of several factors including geological properties of coal seam, seam roof and floor, method of roadway formation, type and spacing of support and so on. Among these factors, strata condition is a main governing factor influencing deformation of roadway. The weak floor rock causes the floor heaving. Water softens some rock and promotes the heaving problem. In this paper, a quantitative discussion on the effect of water on deformational behavior of roadway is given on the basis of results obtained by means of both a field measurement and laboratory rock tests. It is clarified that water content of surrounding rocks affects the deformational behavior of roadway and roadway deforms greater in the faulted zone. From these results a couple of methods for maintenance of roadway are proposed.
Attenuation spectra of seismic signals obtained in a mine adit were examined using the cluster analysis method in order to correlate with the classification of rock masses. The results are summarized as follows; (1) Properties of discontinuity, which are important parameters in the conventional methods of rock mass classification, have a considerable influence on seismic attenuation. We can, therefore, use the character of seismic attenuation as assesments of the fractured state of rock masses. (2) The results of cluster analysis of attenuation spectra agree with each other in spite of the definitions of dissimilarity between clusters. (3) Good correspondence is recognized between the result of the conventional rock classification method and the result of classification by cluster analysis of seismic attenuation spectra. It is a feasible method of characterizing of rock masses.