Abstract: The minable coal seam is distributed in the lower section of Longtan formation coal series in Lancun Mining Area in Youxian County,Hunan Province.The geological background,sedimentary characteristics,stratigraphic sequence characteristics of Longtan Formation,characteristics of minable coal seams of Huanglan Mining Area are discussed in detail,the results show that: Longtan coal series of Lancun Mining Area is formed in the stage of transgression system (sequence 2) of Late Permian,the controlling effects of ancient environment to coal seam formation is significant,which is similar to the geological background,sedimentary characteristics and coal seam genesis of Huangfengqiao Mining Area.Based on the above discussion results,the boundary division standard of the upper and lower section of Longtan formaiton in Huanglan Mining Area (Huangfengqiao Mining Area and Lanfeng Mining Area) is analyzed,so as to provide some reliable for the edge and deep prospecting of coal seam in Huanglan Ming Area.

Key words: Deep prospecting for coal seam, Longtan Formation,Boundary division, Sedimentary characteristics, Coal seam genesis