GB1050201A - - Google Patents

Abstract

1,050,201. Automatic control of mining. COAL INDUSTRY (PATENTS) Ltd. Sept.3; 1963 [Sept. 4, 1962], No. 33864/62. Heading G3R. A mining machine is automatically guided to maintain a seam of constant thickness adjacent to it by intermittent signals dependent on radiation back-scattered from the seam. In Fig. 2 (not shown) the body 110 of a coal cutter-loader machine of the drum shearer type rides on an armoured conveyer 111 and carries a cutter drum 112 and a plough 113, the vertical position of which is adjustable by a hydraulic jack J. A Geiger-M³ller tube in a protective container 119 in the bottom of the plough responds to radiation, from a suitably protected X ray source mounted in a container 118, which is backscattered from the coal seam beneath the plough. The output of the G-M tube, which is thus dependent on the thickness of the coal seam, is applied through a transistor amplifier to a rate meter R, Fig. 3 (not shown), compensated by an integrating capacitor for decay of the source so that a trigger T 1 or T 2 is operated, if the thickness of coal is above or below a predetermined value, to control a hydraulic valve V 1 or V 2 of jack J and lower or raise the machine to follow the seam. This adjustment is made intermittent to avoid hunting by gating circuits CG1, CG2 which are opened at regular time intervals by an oscillator timer T or at regular distances by an inductive device D associated with the teeth of the machine drive and operating through a counter divider GPD. Selection of the type of intermittent operation is by a switch SS. The dotted lines indicate trailing cables permitting location of the control equipment at the end of the coal face where a meter M indicates the depth of the seam. Application to a trepanning type of machine which rides on the floor of the seam is also described and in this case the X ray source is located under the hydraulic jack which operates a potentiometer to produce a follow-up signal.