MATERIAL HANDLING, LIQUID-SOLID SEPARATION, AND PROCESSING EQUIPMENT USED IN MINING, METALLURGICAL AND CHEMICAL FIELDS-NAMELY, BALL, ROD, AND TUBE MILLS, CRUSHERS, CLASSIFIERS, SCREENS, THICKENERS, JIGS, AGITATORS, FLOTATION, LOADERS, UNLOADERS, HOISTING MACHINES, CONVEYORS, HOISTING CAGES, PUMPS, GRADERS, LEVELLERS, MIXERS, AIR MOTORS, COMPRESSORS, SPREADERS, SCARIFIERS, SCRAPERS AND SCRUMER SYSTEMS; AND EQUIPMENT FOR PREVENTING, CONTROLLING AND ABATING ENVIRONMENTAL POLLUTION, USED IN THE TREATMENT OF SEWAGE, WATER, SLURRIES, GASES, AND/OR INDUSTRIAL EFFLUENTS-NAMELY, THICKENERS, CLARIFIERS, AERATORS, FLOTATORS, DUST COLLECTORS, AND LIQUID-SOLID SEPARATORS