Abstract: The position of the cowl on a longwall shearing machine is determined by loads, stresses or deflections measured on the ranging arm, clevis and pin connection on the ranging arm or lift cylinder and its linkage to the machine.

Abstract: A control system having optoelectric detectors responsive to different solids concentrations and character of the solids of a slurry, the signal of the detectors being input to a process controller which adjusts the rate of addition of chemicals to the feed stream of a froth cell to control the separation of solids from impurities. The impurities pass out of the cell as tailings. The controller calculates a feedforward output from the signals from detectors sensing different slurry conditions in the process feed stream, and the controller output adjusts the addition of different chemicals (additives) to the processing cell. The controller also calculates a feedback output after receiving a signal from a third detector in the tailings which monitors the extent of separation and recovery of solids from the processing cell.

Abstract: A control system having opto-electric detectors responsive to different solids concentrations and character of the solids of a slurry, the output of the detectors controlling the addition of a flocculants to the slurry to optimize coagulation of the materials in the slurry. The detectors having outputs sensing different slurry conditions with the detector outputs being processed to control the addition of different flocculants to the cell.

Abstract: The method and apparatus for sensing the coal-rock interface while longwall mining by placing the sensor in the cowl adjacent the shearer drum so that sensor on the leading drum can feedforward interface data for the control of the trailing shearer drum by properly positioning the drum while cutting.

Abstract: A control system having opto-electric detectors responsive to different solids concentrations and character of the solids of a slurry, the output of the detectors controlling the addition of a flocculants to the slurry to optimize coagulation of the materials in the slurry. The detectors having outputs sensing different slurry conditions with the detector outputs being processed to control the addition of different flocculants to the cell.