US 4,281,800 A · Operation of associated crushing plant and mill

Abstract

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. Therefore, the projected 22-hour daily production of mill final product (at 9) is redetermined at the end of each time interval and is the bases for a new target for crusher production.

Claims11

Dependent claims

A method of operating a comminuting facility including a crushing plant (5) to which unprocessed material is fed and by which the material is delivered to a delivery zone (8) as crushed product, and a grinding mill (6) to which said crushed product is fed and which reduces the same to final product (at 9), said method providing for optimum utilization of the capacities of the facility and of the power available to it and comprising the steps of:

A. controlling the grinding mill (6) to produce final product at the maximum rate that is within its existing capabilities while constantly consuming the maximum amount of power available to it;
B. controlling the crushing plant (5) to cause it
(1) to deliver crushed product to the delivery zone (8) at substantially the rate at which unprocessed material is fed to it, and
(2) to constantly consume the maximum amount of power available to it;
C. ascertaining at timed intervals (as by 21, 22, 23) the then prevailing rate at which the grinding mill (6) is producing final product;
and
D. feeding unprocessed material (as by 11) to the crushing plant (5) at a rate such that the projected quantity of crushed product that would be delivered to the delivery zone (8) at the end of an extended period if said rate were maintained to the end of that period would equal the projected quantity of final product that would be produced by the grinding mill (6) by the end of the same extended period if the grinding mill (6) were to maintain its then prevailing rate of production of finished product to the end of said period.

4 more elements

In a comminuting facility that comprises a crushing plant (5) to which unprocessed material is fed (as by 7, 11) and by which the material is delivered to a delivery zone (8) as crushed product, and a grinding mill (6) to which said crushed product is fed and which reduces the same to final product, apparatus for controlling the rate at which unprocessed material is fed to the crushing plant (5) while the crushing plant is so operated that is substantially constantly consumes the maximum amount of power available to it and the grinding mill (6) is so operated that it substantially constantly produces final product at the maximum rate that is within its existing capabilities, said apparatus providing for maintenance of a feed rate that affords optimum utilization of the facility and of energy expended in its operation, and said apparatus being characterized by:

A. clock means (21, 28) for defining a succession of milling measurement times during the operation of the grinding mill (6);
B. a final product sensor (22) for producing an output that is a function of quantity of final product produced;
C. first calculating means (23) connected with said clock means (21) and with said final product sensor (22) for producing at each milling measurement time an output corresponding to the rate at which the grinding mill (6) has been producing final product during an interval which terminates at the milling measurement time;
D. required rate means (24, 28-31, or 42) for producing an output which is a function of the relationship between the amount of time that the crushing plant (5) is in operation during an extended period, reduced to its full-capacity equivalent, and the amount of time that the grinding mill (6) is in operation during a corresponding extended period, reduced to its full-capacity equivalent;
and
E. second calculating means (32, 33, or 41) connected with said first calculating means (23) and with said required rate means (24, 30, 31, or 42), for producing an output that corresponds to the rate at which unprocessed material must be fed to the crushing plant (5).

3 more elements

Dependencies are inferred from the claim text.

Operation of associated crushing plant and mill

Life of this patent

Operation of associated crushing plant and mill

Life of this patent

Abstract

Claims11