The informativeness of roof tremor hazard analysis based on seismic measurements and analytical modelling

Abstract

Rock bursts are a common hazard in Polish hard-coal mines. Their magnitude depends on the state of stress in the mining area, and on underground mining-induced seismicity. Both long-term and ongoing as-sessments of the capacity of the rock mass to generate tremors are based on geological and mining surveys, rock property measurements (in laborato-ries and in-situ) and observations involving signs of rock mass pressure, supported by available concepts applicable to geomechanical and geophys-ical measurements. These include seismic measurements, including profil-ing, scanning, passive/active geotomography and analytical techniques. This paper presents a comparative analysis involving exemplary results provided by both seismic and analytical methods for a selected panel in one of Upper Silesian Coal Basin (USCB) mines. For the purposes of our seismic measurements, we employed seismic tomography for the ge-otomographic reconstruction of velocity fields. Subsequently, we com-pared the results with the results of analytical modelling of rock stresses that relied on classical engineering solutions applicable to problems of me-chanics of deformable bodies. The tremor hazard analysis was based on observations of changes in P-wave velocity distributions in the coal seam environment relative to the evolution of the vertical stress concentration factor at the level of a potentially seismogenic roof layer.

Keywords

• underground mining
• rockburst hazard
• seismic tomography