The report gives results of 36 pilot plant tests, conducted to evaluate the performance of dense-medium cyclones in cleaning fine coal (9x100 mesh) at low specific gravity (1.3). Test variables included two orifice sizes, three medium-to-coal ratios, and six flow rates. The clean coal and refuse from these tests were separated into three size fractions and float/sink tested at eight specific gravities. Performance criteria used in these evaluations included: four dependent criteria (recovery efficiency, misplaced material, yield error, and ash error), three independent criteria (probable error, error area, and imperfection), and three sulfur-based criteria (percent sulfur in coal, percent sulfur reduction, and percent reduction in pounds per million Btu).