ABSTRACT
Present day mining conditions tend to produce coal having more and more complex washability characteristics and therefore lead to an increasing demand for washing processes which will separate coal and refuse with a high degree of efficiency and thus produce the maximum yield of saleable products. Such a separation is accurately accomplished by the simple floating and sinking of the raw coal in a heavy medium, the specific gravity of which may be varied and controlled within very accurate limits to suit the nature of the coal to be treated.
