The coal mine under GCC Energy Co., Ltd. is located in Colorado in the west of the United States. The coal is long flame coal with ash content of 13% - 16%. In 2018, a set of dry coal preparation system with processing capacity of 90t / h was put into operation to discharge reject and reduce ash at the wellhead. After separation, the ash content of the product is reduced to less than 9%, which effectively ensures the stability of product coal quality and fully meets the demand of local cement plants, it completely solved the sales problem for the coal mine.