Rock-crusher
A mill for breaking and crushing rocks; it may also be used for pulverizing quartz, gold or silver ores, plumbago, Portland cement, rosin, foundry facings, etc. Some of the machines used for this purpose will work either wet or dry, and deliver a finished product. Their capacity is 3 to 4 tons per hour on phosphate rock, 1 1/2 to 2 tons per hour on Portland cement, quartz, or ores, depending on hardness of material to be pulverized and fineness of product, and will grind from 30 to 250 mesh with equal facility. See SAND-PULVERIZER.