bhutan gravity separation method of coal washing
Coal Washing Gravity Separation Metho gravity separation method of coal washingKAMY Glossary of Mining Termsrocksandminerals Abutment In coal mining (1) the weight of the rocks above a narrow roadway is transferred to the solid coal along the sides which act as abutments of the arch of strata spanning the roadway and (2) the weight of the rocks over a longwall face is transferred to