Stress state rock mass monitoring ahead of longwall No. 371 202 at 2ndA block, Mine Plant 2, OKD, a.s

Generally, the accurate knowledge of the stress strain state of the rock mass in the neighbourhood of the mining galleries and underground openings is absolutely critical for their precise support designing, not only in the vicinity of them, but also at a greater distance from them if the phenomenon affecting the rock mass stress fields occurs. Measurement (investigation) of the rock stress is usually carried out by interpretation of the rock mass deformation processes, which can be relatively precisely observed and measured. The roadways are loaded not only by rock pressures in the front of the coalfaces but also by destress blasting realised in the overburden rock seam in the scope of the rockburst prevention. In addition, the rock stress distribution is influenced by old mining activities too, for example by abandoned coal pillars in the seams in overburden, respectively by goaf in the excavated seam. All of these factors can significantly affect the stress-strain behaviour of the rock mass around the mining works