Abstract: An auxiliary drive is provided for a drive mechanism for a conveyor, the mechanism including a brake and clutch arrangement designed to facilitate the starting and stopping of the conveyor. The auxiliary drive is conveniently mounted on the mechanism and has a drive motor driving a gear through an intermediate pinion, a gear wheel fixed to the driven stage of the mechanism. The intermediate pinion is movable to engage both the gear wheel and gear to transmit drive from the motor to the driven stage but is actuable to discontinue such drive. The auxiliary drive is intended to provide a means whereby the driven stage may be run at a speed lower than its normal operating speed, a particular application being to conveyors of the scraper chain type which at times require tensioning or detensioning of the chain for maintenance purposes, but at speeds lower than can be achieved using the main drive motor.

Abstract: An apparatus for mixing two flowable substances, such as flocculent and water, comprises a first container into which a first flowable substance is fed and from which the first substance overflows onto an inclined face, the second flowable substance being fed into a second container from which it overflows onto the inclined face and mixes thereon with the first substance, and an outlet for the mixed substances flowing down the inclined face.

Abstract: A transducer for indicating the percentage filling of an underground mine storage bunker. The contents of the bunker is proportional to the rotation of a shaft of a conveyor which feeds it. The transducer comprises a shaft encoder for sensing this rotation and derives a signal indicative thereof. The signal is fed to a circuitry which includes a visual display for a further signal derived in the circuitry which is equal to the first mentioned signal and a bunker full warning light which is energized when the further signal exceeds a preselected value. The circuitry is compatible with a varied range of input signals.

Abstract: A method and apparatus is provided for supporting an underground mine roadway or tunnel having a series of spaced rigid support members installed along the roadway or tunnel, the rigid support members being erected in turn adjacent to newly exposed mine or rock surface as the roadway or tunnel is extended. Deformable bags are arranged between the rigid support members and the adjacent mine or rock surface. In addition deformable limbs extend from the last installed support towards the next support to be erected, the bags and the containers being filled with flowable material including cement and a conveying medium.

Abstract: Apparatus for controlling the steering mechanism of a mineral mining machine having a nucleonic sensor adapted to sense the cutting horizon of the machine's cutter head relative to a boundary of the mineral seam, the apparatus providing an electronic cavity detector which freezes the machine's steering mechanism according to two operational modes when a cavity or crack/undulation respectively is detected. Thus, the machine is not steered in accordance with an erroneous sensor signal derived when the sensor is adjacent to the cavity or crack/undulation.

Abstract: A low-impurity coke suitable for the production of electrodes for aluminium manufacture is prepared by extracting coal volatile matter content greater than about 28% by weight on a dry ash free basis with a highly aromatic hydrocarbon extractant of which the middle 90% boils in the range 250.degree. to 350.degree. C at a temperature of about 380.degree. to 450.degree. C, in the liquid phase, insoluble matter is separated off and the extract is heated to remove distillable oil and coked wherein the residence time of coal in the extraction step is controlled and the weight ratio of extractant to coal during extraction is maintained greater than 3:1 to maintain a substantially constant specific resistivity of the filter cake.

Abstract: The strain in a member is sensed by a strain sensitive device mounted on mounting block means which when fixedly secured to the member include a removable template.

Abstract: A signal derived from means, e.g. a gyroscope, mounted on the machine is used to guide a shearer drum along a straight path, the shearer being mounted on an underframe including two pivotally connected parts.

Abstract: A lute for coke ovens and the like is of clay-like consistency and contains a blowing agent which produces gas at least within the temperature range 160.degree. to 290.degree. C, and can appreciably cut pollution.

Abstract: This invention relates to the extraction of oil shales and tar sands by using a solvent under supercritical conditions at a temperature within 200.degree. C. or its critical temperature in order to effect extraction of kerogen from the sand or shale.In the case of shales considerable heat needs to be applied to the shale before effective extraction can occur and extraction in this case may be carried out at a temperature within the range of 370.degree. to 450.degree. C.

Abstract: Pulse Counter means adapted to determine the position of a mining machine including a rotary member. The pulse counter means includes an arrangement of phototransistors and photodiodes which is adapted to derive electrical pulse signals in response to movement of the rotary member therebetween. Circuitry in the form of logic gates and switching transistors is provided so that operational errors of the phototransistor and diodes are located.The pulse counter means also includes a memory which is kept on by an internal battery when external power is removed so that the counted position is not lost when power failures occur.

Abstract: A fluidized bed apparatus suitable for the combustion of fuel has a baffle assembly arranged in the freeboard above the fluidized bed level. The assembly is in the form of a perforate duct which defines within it a passage connecting with the gas exit of the apparatus. Gases issuing from the bed, in use, and carrying bed material impinge upon the duct and are arranged to follow a vortical path around the duct, resulting in a deceleration of the particles which fall back into the bed. The gases pass into the duct for exhaust substantially free from contamination by bed material. The baffle assembly is of particular value where a gas flows horizontally to a gas exit and prevents or substantially reduces elutriation.

Abstract: A mineral mining machine of the type having a boom-mounted cutter assembly carried by a mobile base unit is provided with a face support structure which is pivotally mounted on the boom. Fluid operable rams are provided for moving the structure between a stowed position lying adjacent the boom and an operational face supporting position perpendicular to the longitudinal axis of the boom. The face support structure is brought into operation when it is desired to afford temporary support to a face of a ripping lip for example, in arch setting operations. In this latter respect, the boom also carries a stowable platform which can be opened out so that operatives may position themselves to handle arch sections which are elevated into position by a lifting mechanism also pivotally mounted on the boom.

Abstract: Coal can be extracted with high boiling aromatic oils produced by extracting the aromatic constituents of a heavy petroleum material, e.g. a bitumen residue, using a selective solvent, mixing the extract with a low-boiling aromatic solvent, adding water and separating the aromatic-containing phase and recovering said aromatic constituents. The resulting coal extract is particularly suitable for the production of electrode coke.

Abstract: Mine equipment for measuring conveyor advance includes two roof support assemblies and control means to ensure each of the assemblies can be advanced only when the other assembly is anchored. The two assemblies are linked by a transducer which senses movement of one of the assemblies relative to the other assembly.

Abstract: Packing paddles for conveying and packing broken rock and debris in a mine are pivotally mounted on mine roof supports. Hydraulic sequence valves are employed to operate hydraulic rams controlling the paddles. The valves, and thus the paddles, are operated in sequence to convey the debris from paddle to paddle.

Abstract: An elongated frame provides a track over a mining machine for a carriage which is hauled along by an endless chain. The carriage carries assembled crown roof support sections to adjacent the newly exposed rock boundary.

Abstract: A longwall mining machine traverses to and fro along an articulated track assembly which includes an armoured face conveyor and which is engaged by a driven pinion on the machine body to haul the machine along its path.

Abstract: The invention discloses a novel damp proof composition, suitable for making into sheets for roofing purposes, comprising (a) from 5 to 40% of a polychloroprene rubber, (b) pitch in an amount of up to 45%, and (c) at least 5% of a filler. The filler may be particulate or fibrous, and the composition may further include a supplementary polymer, for instance a nitrile rubber.

Abstract: A mineral mining machine which wins a strip of mineral by separate roof and floor cutting stages comprises steering apparatus which senses the cutting horizon associated with one cutting stage to control the cutting horizon associated with the other cutting stage.