Illyashov M. Coal seams liable to gas-dynamic events.- Mining efficiency and safety in increased rock pressure zones.

A new hypothesis of preserved structural changes in coal and gas-dynamic abnormalities due to increased rock pressure, after the IRP source withdrawal, has been set up and experimentally tested. It is based on gas-dynamic statistics for Donbass coal mines, coal seam stress/gas-dynamic behaviour in IRP zones, both laboratory and field tested, and stress analysis of rock mechanics in stoping areas. Coal seam beheviour within an IRP zone has been identified according to the IRP source type and distance from the working seam, range formation and crossing direction, outburst seam danger index. Techniques have been developed to overmine IRP zones, overmine and undermine rock-falling seams. Estimation procedure has been set up to assess risks in IRP zones by in-situ stress and gas-dynamic criteria. Safety mining procedures for IRP zones have been worked out, the innovations have been esfimated in terms of cost effectiveness