Fracture of Solid Inclusions by Picks

According to classification of coal seams with solid inclusions, all mine seams are divided into three groups subject to the size and content of the inclusions in a seam. It is found that fracture efficiency and maximal loads depend on the mineral type of inclusions. Carbonate and pyrite inclusions are fractured in a few cuts, while carbonate–pyrite inclusions are usually broken in a single cut. The loading of a pick is approximately 1.6–1.7 times higher in cutting pyrite inclusions as compared with carbonate inclusions. The authors identify five basic types of the pick–solid inclusion interaction: central and edge cut; touch; tear-out; extraction. The highest loads appear in cutting of solid inclusions and should be taken into account in designs of cutting heads and power drives of mining machines.