Estimating the rockburst hazard of hard rocks based on laboratory test results

The relevance of the problem under study is based on the fact that dynamic fractures of mine workings occur in rock masses when developing mineral deposits. Safety assurance of mining depends on the awareness of proneness of various rock types to brittle failure. By now, experimental methods have been elaborated to determine rock deformation and strength properties under various loading conditions. A common drawback of the approaches in use is that they do not expressly consider the main condition of dynamic rock fracture - rock mass ability to accumulate energy when loaded. The studies have been conducted to analyze the nature of elastic energy accumulation during loading and deformation of samples of various rocks under uniaxial compression to estimate the degree of their rockburst hazard. The approach is original as it studies the deformation curve of rocks at the pre-peak stage that may be obtained with any standard equipment without the use of special-purpose test ("rigid") devices. Results of the studies conducted on standard test devices have allowed the authors to identify two different deformation patterns for the rock type tested with further establishment of criteria of rock classification by the degree of proneness to dynamic fractures. This approach is of practical value as it specifies the geomechanics zoning method of the rock mass and improves the assessment of rockburst hazard degree of specific areas at deposits being developed.