THE CRUSHING OF ANTHRACITE WITH A JAW CRUSHER

Special Research Report SR-4 Pilot plant tests have conf irmea laboratory experiments ani indicated that the jaw crusher may be usea to reduce the domestic sizes of anthracite to steam sizes and produce only a small amount of extreme fines. The tests were conductea using a 10 x 20 inch Jlake-type jaw '· crusher with the minimum 3/8-inch set. Egg, stove, and nut coal were used in the tests and the distribution of sizes in the products was approx~mately constant regare- less of the feed size. The amount of buckwheat producea ranged from 37 to 39'7. of the feed, the amount of rice from 16 to 19'7., and the amount of barley from 12 to 14%. The amount of No. 5 and smaller ranged from 7.1 I to 8.7'7. and the amount of oversize consisting of nut and pea rancea from 17.2 to 17.5'7.. The crusher was operated with a 25 HP motor at 270 revolutions per minute and at a feed rate of from 8.1 to 8.7 tons per hour. Operating costs for this type of duty in a plant installation should be very low, not exceeding 5 cents per ton for operating labor, maintenance and power, and probably would be of the order of 2-3 cents. Power consumption for a 10 x 20 inch crusher would be of the order of O.l-0.5 kw•hr per ton crushed.