Coal quality characteristics of coal seam in Laogongyingzi mine field

In order to make economical utilization of the coal in Laogongyingzi mine field,this paper studied the coal quality characteristics based on the geologic profile,the sedimentary cycle of coal-bearing strata and the physical and chemical properties of coal.And the relationship between the chemical composition of coal and the depth of coal seam was analyzed to determine the industrial properties and the use of coal.The results show that the lithotypes of the coal is dominated by clarain and durain; and the coal maceral is mainly composed of vitrinite.The content of chemical components in coal seam is more obvious than that in coal seam with depth of 200-350 m,and it is more stable with the increase of burial depth.The average internal moisture content of raw coal is approximately 6.09%-10.28%,the average ash content is ca.16.93%-25.80%; and the average sulphur content is ca.0.78%-1.47%,as well the average volatile content is more than37%; while,the contents of other elements are low.Obviously,the coal is with medium ash and sulphur contents.According to quality evaluation method,i.e.,the region's average gross calorific value,constant humidity gross calorific value,transmittancy etc.,the coal belongs to a medium-low calorific value of No.2 lignite.Because of its medium-low calorific value,poor thermal stability,high chemical reactivity with CO_2 and medium tar yield,the coal can be used as a raw material for steam coal,gasification coal and coking coal; and thus it can have a greater economic value.