Assessment of the hazards caused by gas dynamic phenomena based on analyzing in-situ and laboratory studies of elastic wave propagation velocities in the host rocks of the Internatsionalnaya kimberlite pipe

The article discusses a method of zoning rock masses by their physical and mechanical properties using the velocities of elastic waves propagation obtained in laboratory conditions when studying core samples and in situ conditions when processing seismic datasets of process blasts performed in driving mine workings at the Internatsionalnaya mine. The velocities of elastic primary and secondary waves propagation in rock samples were determined using the “Ultrazvuk” instrument. The ultimate strength of rocks under uniaxial compression was determined by means of a test press using cylindrical specimens with the height-to-diameter ratio of approximately 2:1, which corresponded to the height of 60±2 mm with the diameter of the specimens being 30±2 mm. The results of laboratory tests indicate that the values of primary wave propagation velocity correlate with the values of uniaxial compression strength of the core samples. The combination of laboratory and field tests is promising for using in further forecasts and calculations of parameters for measures to prevent gas-dynamic phenomena. The obtained results indicate that the value of uniaxial compressive strength of bituminous dolomite rock mass should be taken as 60 MPa for further forecast calculations.