The origin of coal measure breccia in Jinggong No.3 Coal Mine, Pingshuo, Shanxi

The genesis and occurrence of coal measure breccia in Jinggong No.3 Coal Mine of Pingshuo are special and closely related to the coal seams. Through core observation of supplementary drilling, combined with regional geology and analysis of previous drilling data, the composition, structure and structural characteristics of breccia in the study area are described in detail, and the horizon, thickness and distribution of breccia are delineated. It is found that the composition of breccia in Jinggong No.3 Coal Mine of Pingshuo is complex, and the size of breccia is different. The maximum diameter of mudstone is more than 1.20 m, which is mainly angular, and the sorting is very poor. The top and bottom interface of breccia is obvious, which is close to or appears in the coal seam, and the transverse continuity is poor. Breccia destroys the continuity of coal seam, with more in the north and less in the south, and its distribution is limited. It occurs in lenticular shape, and its long axis points to the northwest provenance. Vertically, breccia decreases from bottom to top. The results show that plant anchorage is strong in the coal accumulation period, terrigenous debris and side slope are confined by vegetation and accumulated vertically within a limited range, forming a debris reservoir with steep slope. Peat net interwoven with vegetation and peat is on the surface of peat swamp, and paste peat with deep degradation at the bottom provides a favorable slip surface. The unexpected events lead to the collapse of the slope and breccia reservoir in the provenance area, rush over the peat net, be teared into a peat raft and transported by the peat raft, intermittently deposit, and be transformed. The distribution law and genesis of breccia is of great significance genesis and thickness variation of coal seam, estimation and exploitation of coal resources/reserves. It may be more reasonal to explain the genesis of coal measures sedimentary breccia with peat raft transport model.