There is an increasing amount of rock in ROM coal in many coal mines, both underground and surface operations, due to changing geological conditions. This usually results in increased haulage and processing costs, especially if the processing facility is far away from mine sites. In this case, the FGX dry coal equipment can be applied near the mine site or prep plant for deshaling. By doing this, some or even most of the pure rock can be removed from ROM coal prior to haulage and feeding to prep plants. Prep plant deshaling or mine site deshaling, in turn, saves trucking and processing costs. Since the quality of deshaled product is much better than ROM coal, the feed to prep plant becomes much “cleaner.” Therefore, the overall prep plant productivity is improved.
The hard rock in coal is a major factor for coal prep equipment wear. It is known that maintenance costs typically account for around 40% of the operation cost of a wet processing plant. Thus, plant maintenance costs can be significantly decreased since rock is rejected by the FGX circuit before entering the wet process.
Shale in some coals can easily break into small clay particles once meeting water. The tiny clay particles pose serious changes to water treatment system at prep plants. This problem can be alleviated if coal deshaling is applied prior to prep plant, which keeps the prep plant feed from generating large amount of clay.
Removal of pyritic sulfur can be another benefit for some high-sulfur deshaling applications using FGX technology. In some high sulfur coals, pyrite in shale is the major source of sulfur. If the pyrite is well-liberated, good separation can be obtained using FGX due to the fact that pyrite density is much higher than that of coal.