Malcolm D. Flavel - Appleton WI
Allis-Chalmers Corporation - Milwaukee WI
A method for operating a crushing and grinding facility is disclosed in which crushing of mine-run material is controlled to always match grinding feed requirements while both crusher(s) (10) and grinding mills (16) operate full time and draw full power during the hours of what may be unequal length working days. The grinding mill (16) is also operated to produce the maximum output of final product that is within its existing capabilities. At each of a succession of measurement times (e. g. , every 1/2 hour during a 22-hour working day of the mill), the rate of production of final product by the grinding mill (6) is ascertained (as by 21, 22, 23) and projected to the end of the mill working day. At each such time, feed of mine-run material to the crusher (10) is adjusted (as by 27-33, 11) to a rate which, if maintained through the remaining portion of an 18-hour crusher working day, would cause production of a target quantity of crushed product (at 8) which would equal projected total daily production of ground product (at 9 ). However, the mill (16) will not maintain its prevailing rate of production because grindability of crushed material is unpredictably variable.