Abstract: The heavy medium separation system of the No. 1 Mine Washery is facing the trouble that the loss of coal in refuse goes beyond the specified limit, which leads to as a result more liability of refuse to undergo spontaneous combustion and decrease of yield of clean coal. To address this problem, analysis is made of the factors behind the high loss of coal in refuse in separation using the shallow-bath heavy medium separator, and based on analysis, corresponding technical measures are adopted. The adoption of the measures has led to less loss of coal in refuse, reduced environmental pollution and improved social and economic benefits.