Seismic activity and compression strength of roof rocks in Lubin copper ore deposit

摘要

Lubin copper ore deposit belongs to the Fore-Sudetic monocline, situated in the southwest of Poland. Rock tremors and their effects such as rock bursts, which have been occurring since the very beginning of the deposit mining, are the major natural hazard in underground mines operating within the region. Consequently, rockburst prevention has to play the key role in mining technology to provide work safety and minimize costs. Evaluation of the rockburst hazard should start with geological recognition that embraces rock geotechnical testing and observations while extracting the deposit. Rock samples are obtained from surface boreholes and those drilled in working panels. Geological and geotechnical parameters of rocks such as compression strength, roof stability index, tectonic ratio and thickness of banks are the necessary parameters to classify roof rocks in relation to rockburst hazard degree. Since compression strength of roof rocks is of critical importance to seismic energy accumulation and release the assessment of rockburst hazard degree needs the analysis of seismic activity in relation to that parameter. Compression strength of roof rocks and seismic activity in Lubin copper ore mine in 2005-2007 years are analysed in the paper. Selected the four panels have different mining and geological conditions and show diverse activity. The results of statistical analysis of roof rocks compression strength such as its variation coefficient are presented. The influence of compression strength variation of roof rocks on the number and energy of tremors is analysed using contour maps made for the whole mine areas and for selected working panels.