Coal-accumulating Pattern Of No.5Coal Seam In Chenjiagou Minefield

The Chenjiagou minefield is located in the southwestern part of Huating coalfield ofGansu. Laying on the transition zone of Liupanshan rock belts and the Loess Plateau,the coal reserves of this minefield is abundant. The main minable No.5coal seamcontains high quality coal with features of low ash, low sulfur, high calorific value andlong flame. In recent years with the improvement of local traffic, and the gradualimprovement of other supporting facilities, major changes have taken places in theinvestment environment, so that coal supply appeared in a tense situation. In order toprovide a basis for coal mining in the future, we should research on coal-bearing stratain this region, and summarize the coal accumulating regulation and control factors.This article is based on the predecessors’ research, combining with the petrology,sedimentology, tectonics and coal geology method. Through the analysis of thelithology and structural characteristics of Yan’an group, the author divided thecoal-bearing strata into three sections and four sedimentary cycles. On the basis of fullgrasp of the coal quality characteristics and the changing rule of the trace element, theauthor concluded that the sedimentary environment of No.5coal seam. Combiningwith the depositional facies, infer the No.5coal seam formed in a set ofalluvial-fluvial facies-inland lake delta-swamp, peat swamp facies sedimentarysystem. This is the first time to discuss the source of the gravels in coal seam, whichcontributes to the study of sedimentary environment affected by sedimentaryenvironments, tectonic, ancient climate, plants, and the control effect, the change of thecoal seam is complicated. No.5coal seam in the eastern part of the area is thicker andin the west is relatively thin. Coal concentrated in the syncline axis and the east wing,but layered in the west wing.