GB717136A - Improvements in the stowing of waste in mines - Google Patents

Abstract

717,136. Filling goafs. RIO TINTO CO., Ltd. Oct. 2, 1952 [Nov. 7, 1951], No. 26073/51. Class 85 [Also in Group XXX] Goafs in mines are filled by compacting material in a breech while air is being compressed in a receiver to form a charge under adequate pressure and then projecting the compacted slug of material from the breech by the rapid release of the charge of compressed air. Material is forced into the breech 1, Fig. 1, from a hopper 3 by a screw 4, the diameter of which decreases progressively towards the breech. Compressed air stored in the receiver 6 is admitted to the breech through the bell-shaped connection 7 when the valve 9 is opened. The spindle of this valve is attached to a piston 11 of smaller area than the valve 9 working in a cylinder 12 open to atmosphere. A downward extension 13 of the spindle carries a piston 14 working in a cylinder 15 connected to a compressed air supply. The screw 4 is driven by a shaft 22, Fig. 3, which is connected to a shaft 21 driven by a motor 18 by a dog clutch 19, 20. The member 20 is keyed to the shaft 22 and the member 19 is slidably mounted on splines in the shaft 21. The engaging teeth of the members slope at an angle of about forty-five degrees and the members are urged together by a strong compression spring 23. The compression of this spring is adjusted so that the members 19, 20 become disengaged completely when the screw 4 experiences a resistance corresponding to the desired compression of the material. A secondary clutch consisting of sleeves 26, 27, with only one pair of sloped mating teeth, is fitted coaxially over the members 19, 20, the sleeve 27 being secured to the member 20 and the sleeve 26 being slidably but non- rotatably mounted on the member 19. The sleeves are maintained in close contact by light springs 28. The arrangement is such that the member 19 is disengaged completely from the member 20 before the sleeve 26 commences to disengage from the sleeve 27. A flange on the sleeve 26 bears against a rod connected to a control valve 30 and moves it to admit compressed air to the cylinder 15 to open the valve 9. When the sleeves reengage, the compressed air returns the valve to the position shown. The receiver 6 contains a watertight partition 32 which does not extend to the top and surrounds the valve assembly 9, 10, 11. The space for compressed air can be reduced by running water into the outer zone of the receiver.