Coal quality characteristics and coal accumulation patterns of seam No.4 at medium depth in Longting mining area, Weibei P-C Coalfield

Abstract On the basis of collecting the latest exploration data of the study area, the authorsmade the research of the coal quality characteristics and coal accumulation patterns of seam No.4 at medium depth, which provided geological basis of the construction of high production and efficiency coal mine and the next coal resources exploration. The results show that the seam No.4 is black - brown-black, semi bright coal type, at the VII phase of the medium rank coal, high calorific value, easy to grind, nonagglutinating, noncoking and at the relatively high - high softening temperature gray level. The raw coal of seam No.4 generally belongs to middle ash coal, ash yield gets higher from south to north. It’s given priority to a low ash coal in the south and middle ash yield coalin the north. The seam No.4belongs tolow-sulfur coal, and shows “dumbbell” type in sulfur contour map, withthe basic characteristics of low in the middle, high on both east and west sides and higher in southwest, lower in northeast. The thickness and deposition range of the seam were controlled by ancient fluvial erosion after the coal-accumulating period around the Qiao8-11 holes in the south of study area and in the other area, during the coal-accumulating period were controlled by syndepositional structures.