Development Characteristics of Coal-bearing Sand Body in South-central of Tiefa Mining Area——Both on the Prediction about Lithologic of Coal Seam Roof and Erosion Zone in Coal Seam

摘要

With the application of phase analysis method,coal-bearing sand body in south-central of Tiefa mining area is divided into genetic types of anastomosed channel and braided channel sand body.Thus it reveals the respective characteristics of the two types of sand body.In sedimentary section diagram of anastomosed river,anastomosed channel sand body is surrounded by siltstone and claystone ;on the sand body thickness contour map,the high value area of anastomosed channel sand body is interwoven mesh;anastomosed channel sand body is located in the lower part of the sequence of the anastomosing river,the granularity of which is thinner upward.In sedimentary section diagram of braided river,the fine clastic rocks of the flood basin deposition are not developed surrounded by braided channel sand body;on the sand body thickness contour map,the high value area of the braided channel sand body shows the small camber width bebraided river channel sand body constitute the main body of braided river facies sequence,the granularity of which is thinner upward.On the basis,the No.15 coal points out that the coal seam roof is made up of anastomosed channel sand body in addition to the southeastern anastomosed channel sand body,the extent of which is nearly SN ;the anastomosed channel sand of the coal seam roof in other area is in NE extension as a whole.Erosion zone in coal seam is mainly located in the high value zone of the coal roof sand body.