Traditionally in coal processing jigs have been used to clean the coarse coal fraction, the +3/8″ or +¼” material. Today with the advent of modern fine coal jigs in the United States, its place was moved from the coarse to the intermediate coal circuit, the 3/8″ x 100 mesh.
Recent theoretical performance and economic evaluations indicate the Batac jig may be the most economical unit for washing intermediate size coal in a metallurgical coal cleaning plant. Consol has traditionally used heavy media cyclone hydrocyclone circuits, for washing the intermediate size coal at low gravities. However, recent theoretical calculations using Batac jig performance data indicate a Batac jig circuit that incorporates a heavy media cyclone rewash of the jig’s middlings product can produce the same yield at a given quality specification. The jig also has a processing advantage over the heavy media cyclone circuit. Heavy media cyclones, like tables, are refuse sensitive and have a tendency with increases in refuse load to kick some of this refuse out with the clean coal.
If jigs are the intermediate size coal machine of the future, what is it like to operate them? Consol presently operates two Batac jigs: the Shoemaker jig which has been operating for 3-½ years and the Dents Run jig which has operated for one year.
To achieve the ease of operation just described and to operate as efficiently as it does, the Batac jig has some very sophisticated controls. The unit also requires some operator adjustments to maintain operating efficiency. But, unlike the heavy media bath or heavy media cyclone where the only operating adjustment is the media gravity which is easily measured, the jig has many adjustments that control the performance. In addition, adjustment of the jig is subjective in nature and washability tests are required to accurately measure the performance.