Wind Sifter Separator for Coal Beneficiation by J Alade.pdf

No single method gives a continuous, real time report on how a coal preparation plant is performing. Mass meters converted to yield values, on-line ash and moisture monitors, load cell chutes and automatic medium density control together supply most of what is needed. Measuring discard and slimes tonnages, particularly slimes disposal, remains the weakest point in plant accounting.

No surface geophysical method can map individual bords and pillars at the depths typical of the Witbank coalfield, a limit the review attributed to physics rather than to technology, since the targets are small relative to their depth and conductive layers often lie above the seam. Borehole laser scanning remains the workable option, with sonar suited to flooded workings.

The separator handled fine coal and produced a 28 MJ/kg product, but its measured separation efficiency was lower than that of conventional dense medium cyclones and it was harder to operate. Two efficiency tests produced no evidence that the unit outperforms cyclones on fine coal, so cyclones were recommended when the plant was rebuilt at its next site.