Abstract: There is a considerable loss of clean coal in middling product. Following an introduction to the technical features of the 3GDMC1000/720AI gravity-fed 3-product H.M. cyclone in operation at the plant, an analysis is made of the factors causing the misplacement of clean coal in middling. After taking a series of remedial measures, the loss of clean coal is reduced by 10.56 percentage points with a rise of flotation concentrate by 0.20 percentage point, making it possible for the plant to recover additionally 240, 000 tons of clean coal per year.