The coal type of Donghai Coal Mine is 1 / 3 coking coal. Due to the large amount of reject, it can not be directly sold as electric coal. As coking coal, it is transported to the central coal washing plant for washing, which has the problems of high transportation cost, low clean coal recovery rate and large equipment wear and tear. In April 2016, Donghai coal mine cooperated with Shenzhou group to build a 1.5mt/a dry coal preparation production line in BOT mode to pre discharge reject, it can save 35% of the ineffective transportation cost of reject and improve the recovery rate of clean coal.