GB2027094A - Mining of Minerals - Google Patents

Abstract

Coal or other mineral is mined by a mineral cutting machine 10 which travels the free line of the seam by cutting in the buttock or heads into the seam. The machine 10 is connected to a remote power plant 26 providing the services for the machine 10 by an umbilical cord entity. The latter includes a vacuum tube 22 along which the won mineral is conveyed to the main transportation line 25 of the mine or to any other convenient location. <IMAGE>

Description

SPECIFICATION Mining of Minerals This invention relates to the mining of minerals.

Currently, coal is mined by the longwall method and the machinery usually installed on a coal face comprises a coal winning machine, usually a shearer type power loader traversing the face length and being mounted either directly on the floor or on an armoured conveyor, the controls of the loader being generally mounted directly thereon, but remote control is possible; a conveyor, generally a heavy duty armoured steel fabrication, capable of being snaked forward as the winning of the coal progresses; and supports, which are, in the main, of the self-advancing hydraulic kind. However, increasing consideration is being given to shield type supports by the mining industry.

Accepting that a winning machine is essential to extractive mining of coal, the other major parameter involved is to transfer the coal from where it has been deposited after cutting to the roadway transportation system. If this can be done in a flexible compact manner, a physical size reduction or even elimination of allied supports would be possible. With elimination of face supports, it would not be possible for men to operate at the face. Hence, the winning machine would require to operate and steer automatically, and further, in the event of machine failure, provision would need to be made to withdraw the machine to a supported place.

Winning machines employed in the mining of coal are generally not satisfactory in the mining of other minerals, which tend to be of harder nature and it is usually necessary to resort to drill, fire and load operations. Resulting from this greater hardness and rock strength the need to use portable or advancing supports adjacent to the face become less of a requirement.

Hence, the primary requirements for mining such other minerals are a competent cutting machine, flexible means of transferring the won mineral to the main transportation system, and ideally remote machine operation and control.

In summation, it can be seen that to win materials from a longwall face operation, in theory, there are two prime requirements, namely a competent machine to readily cut or break-out the mineral, and means to transfer the cut mineral to the main transportation system.

Within the face winning system as a whole, several other factors are of importance, i.e.

ventilation, strata behaviour, machine power and control, and recovery of machine in the event of failure.

It is the object of the present invention to satisfy these requirements.

According to the invention, there is provided a mining system comprising a mineral cutting machine adapted to travel the face line by cutting into the buttock, and vacuum transportation means including a flexible or non-rigid tube for extension alongside the newly exposed face line for transferring or depositing the mineral into the main gate road transportation system or other desired location.

The major areas of application of this mining system are: 1) the collection at the point of winning of mineral on a longwall/shortwall face; pillar and stall type working or other mineral extractive mining, and transfer along the tube to the ongoing transportation system; 2) the collection at the point or position of winning rock and/or mineral in the drivage of underground tunnel, roadway enlargement or underground excavation, and the transfer along the tube to other associated transportation system or deposition in other part of underground excavation, e.g. ripping face and pack; 3) the collection and transfer along the tube of carry-back material at conveyor drive head or transfer point; 4) as a material feeder of solids such for example as cement and bentonite.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a diagram of a mining system in accordance with the invention in use in the mining of coal or similar minerals; Fig. 2 is a perspective view of a coal winning machine adapted for the system; Fig. 3 is a perspective view of the power pack and vacuum unit of the system; Fig. 4 is a diagram of the mining system in use 'for winning harder minerals; and Fig. 5 is a detail view of the winning machine shown in Fig. 4.

Referring to Figs. 1 to 3, the coal winning machine is a hydraulically or compressed air powered crawler 10, or other self-advancing type unit, on the front of which is mounted a cutting head 11 of chain, or rotational pick drum or drums, or rotary/percussion cutting elements. The winning machine operates by cutting into the face buttock.

A specific winning machine 10 is a hydraulically powered crawler unit 12, four feet wide, driven by independent two-spaced track motors. At each end is a four feet diameter ranging cutting drum 13 equipped with hard metal cutting picks 14 and 4'6" wide serving as the cutting head 1 The rotational drum 13 is carried by an oscillating arm 1 5 and is continuously oscillated in the vertical plane by a hydraulic ram (not shown) to establish the roof and floor line, but a sensing device (also not shown) is provided to vary ram stroke and consequently the magnitude of oscillation if desired.

Such a device is preferably a gamma ray sensor, which is already known in the mining industry, and which may be housed within the cutting head 1 This sensor will through suitable control circuitry (also known) effect ram stroke variation.

A guide bar 16 is affixed alongside the face side track and maintains contact with the newly cut coal face. This senses the face, and, through direct contact, hydraulic valves 1 7 adjust the speed of the track motors if necessary to maintain the established face line.

All operations function on supply of hydraulic power by twin pressure hoses 1 8 with a common return. One power hose feeds the track motors while the other feeds the cutting head assembly.

The hoses 1 8 are carried in wire support brackets 19.

Directly behind and beneath the cutting drum 13 is an apron plate 20 of similar width to the drum, fitted with side collector/baffle plates 21 which guide the cut coal to the vacuum collection inlet.

In some instances, the transfer of the coal/mineral may be assisted by mechanical arms our a rntationaldisc incorporated in the ram plate.

The cut coal may alternatively be deposited on the newly exposed floor at a vacuum pick-up point.

Commencing at the suction collection point at the rear of the plate 20, the vacuum transportation means is a 6" diameter tube 22 passing through the body of the crawler base and continuing in flexible form throughout the face length. The flexible tube is coupled to the machine and is connected at intervals of four or five feet to a wire or similar rope (not shown).

The hydraulic hoses 1 8 are also coupled to this wire rope which is fixed to the winning machine so that the vacuum tube 22, hydraulic hoses 1 8 and wire rope form an umbilical cord entity between the winning machine 10 and a power hoist (not shown). This wire rope relieves the strain on the vacuum tube 22 and hydraulic hoses 18 and provides a means to retract the winning machine 10 in the event of mechanical or other failure by the power hoist.

A 6" diameter tube is capable of passing at least 100 tons of coal per hour. The umbilical cord entity is self-tensioning and of a fixed length greater than that of the face. In the main roadway, it is preferably supported by a mono-rail 23 which accepts or releases, at the face line, the connectors 24. The mono-rail 23 is located directly above the main transportation line 25 thereby allowing discharge onto a belt conveyor or a stage loader/bunker or into a pneumatic pipe.

In use, the winning machine 10 cutting into the buttock will always be immediately adjacent the newly exposed side and frontal spaces, and the flexible or non-rigid vacuum tube will generally take a position adjacent to the base or foot of the newly cut face.

While the winning machine could have its prime mover directly mounted thereon it is preferred as aforesaid that the power plant be remote and preferably be located in the face gate roadway.

The power pack 26 for winning machine 10 is located near to the face line in the main roadway and incorporated on a crawler base 27. It comprises an FLP electric prime mover 28 driving hydraulic pumps 29 in communication with a hydraulic fluid tank 30 and a high capacity oil cooler 31. A self-tensioning cable reel (not shown) for the electric cable and all the hydraulic controls and safeguards.

It further includes high pressure blower fans 32, 33 driven by an FLP electric motor 34, a high vacuum filter/receiver unit 35 operating in the horizontal place, the coal being deposited from the latter onto the main transportation line 25 through a rotary valve 36.

The clean air exhaust stack from the blowers 32, 33 is indicated at 37.

In use, the winning machine 10 is set to cut into the buttock from controls fixed to the electrohydraulic power pack 26 connected to the machine by the umbilical cord entity. The oscillatory ranging cutting head 11 is first operated, followed by the crawler tracks to advance the machine into the coal.

The vacuum transportation motor 34 is in sequence with the cutter head 11 and the cut coal is drawn along the tube to be eventually discharged onto or into the main road transportation line 25. The umbilical cord entity supplying the services to the winning machine is aligned to lie at the bottom and adjacent to the new face.

Roof supports (not shown) are provided adjacent the newly exposed coal face. These will normally be conventional self-advancing supports which are automatically triggered into forward movement upon passage of the winning machine 10.

The mining system of Fig. 1 also shows boom cutting machine 38 used, as is customary, to cut the underground tunnels and roadway enlargements. With these machines, vacuum tubes (not shown) may be used to pick up and transfer the cut mineral or material.

After transfer deposition could be to the main transportation system 25, or where underground roadway support packs 39 are being constructed in conjunction with a longwall coal face, the material could be deposited within the receiver 35 of the power pack 26, taken therefrom and then "blown" into the adjacent pack 39 using the exhaust air in the manner of a low pressure blower. Alternatively a separate pack forming machine 40 is used.

The abovedescribed mining system provides a method of winning coal or similar mineral from a longwall or shortwall face.

Referring to Figs. 4 and 5 there is shown a mining system suitable for mining minerals which are harder than coal.

The winning machine is indicated at 41, the power plant which is identical with power plant 26 at 42 and the vacuum tube/hydraulic hose/wire rope umbilical cord entity at 43.

Due to the fact that the winning machine 41 operates at a higher level than the power pack 42 the vacuum tube 43 is elevated by and supported on a launching platform 44.

The winning machine has, due to the harder nature of the minerals to be won a cutting head 45 of a type using the high energy percussion cutting principle.

Here, the high energy percussion blow energy is applied to each of two face cutters 46 constituting the cutting head 45 and each of which is circular in shape and rotated or oscillated in phase with the blow application. The face cutter physical dimension is related to the input blow energy and mineral hardness the disburse and transfer the energy over a maximum face area, commensurate with the local cutter point requirement to break-out the mineral. the vacuum collection point is indicated at 47 immediately behind and below the face cutters 45.

Advantages 1) Possible manless face with personnel health and safety advantages.

2) Substantial capital and maintenance cost saving by size reduction of face supports and elimination of conveyor structure.

3) Possibility of no electrical equipment on coal face.

4) Automatic controls, giving more precise cutting and a potentially cleaner product; better face alignment and more consistent roof and floor horizon.

5) Remote, automatic control leading to improved results by enabling equipment to operate close to design performance.

6) Possibility of tube transportation to pit bottom and even into washing plant.

In longwall coal mining the won coal is generally transported along the face line by an armoured face conveyor, and at the point of discharge there is a tendency for small coal or dust to be fed back under the conveyor structure.

It is envisaged that the vacuum system provides a means to transfer the detritus coal back to the main transportation after physical collection and eliminate the problem of build-up.

To assist the detachment of the residual dust or coal from the moving chain or flight bars, jets of air could be directed from tubes situated in the conveyor structure. This air could be exhaust from the vacuum blower of the power plant. Generally a flexible brush type arrangement would be fitted to assist dislodgement of the dust or small coal from the chain/flights.

Claims (11)

Claims

1. A mining system comprising a mineral cutting machine adapted to travel the face line by cutting into the buttock, and vacuum transportation means including a flexible or non rigid tube for extension alongside the newly exposed face line for transferring or depositing the mineral into the main gate road transportation system or other desired location.

2. A mining system as claimed in Claim 1 in which the vacuum transportation tube is included in an umbilical cord entity for connecting the cutting machine to a remote power plant which includes blower means to create the necessary vacuum.

3. A mining system as claimed in Claim 2, in which the umbilical cord entity also includes a wire or similar rope to which the vacuum transportation tube is detachably connected at intervals, the rope relieving stress on the tube and providing a means for recovering the cutting machine in the event of breakdown.

4. A mining system as claimed in Claim 3, in which the cutting machine is a pressure-fluid powered, self-advancing unit having a leading cutting head, pressure fluid delivery hoses from the power pack also forming part of the umbilical cord entity and being detachably secured to the wire or similar rope.

5. A mining system as claimed in Claim 4, in which the entry to the vacuum transportation tube is behind and below the cutting head, the won mineral being delivered to said entry by a ramp or apron plate of the cutting machine.

6. A mining system as claimed in Claim 5 in which the ramp or apron plate has lateral guide walls.

7. A mining system as claimed in Claim 5 or 6, in which mechanical arms or a rotational disc is incorporated in the ramp or apron plate to assist transfer of the mineral to the vacuum transportion tube.

8. A mining system as claimed in any one of Claims 2 to 7 comprising a mono-rail for supporting the umbilical cord entity for part of its travel.

9. A mining system as claimed in any one of Claims 2 to 8 in which the power plant includes a filter or receiver into which the vacuum transportation tube delivers the won mineral.

10. A mining system as claimed in Claim 9 in which the filter or receiver has a rotary outlet valve through which the won mineral can be egressed.

11. A mining system, substantially as hereinbefore described with reference to Figs. 1 to 3 or Figs. 4 and 5 of the accompanying drawings.