ABSTRACT
Blasting is the oldest method of direct burst control. It is the preferred means of coalwinning in view of possible burst occurrence while the coal breaks. It is also applied to roof strata to facilitate caving, but normal destressing blasting is done in the seam to eliminate dangerous stresses in the coal. Destressing blasting can also be effective when a longwall face is endangered during long periods of advance. The destressing effect may be insufficient where the local stresses are extremely high. The destructive effects of moisture on shaly layers may reduce the burst danger but is more often likely to result in problems of roof control or floor heave. The seam is to be fractured hydraulically before it can fracture in the form of a rockburst. The seam was 1.7 to 2 m thick so that the desired advance of 3 m or more per day became possible.
