GB2263292A

GB2263292A - Profile measurement and control of a mine face

Info

Publication number: GB2263292A
Application number: GB9200867A
Authority: GB
Inventors: Robert Graham Harris
Original assignee: MECO ELECTRONICS Ltd
Current assignee: MECO ELECTRONICS Ltd
Priority date: 1992-01-16
Filing date: 1992-01-16
Publication date: 1993-07-21
Also published as: GB9200867D0; AU2975392A

Abstract

The profile of a mine face 10 is measured by taking a gyroscope 26 capable of producing an output signal representative of the profile of the mine face 10 if transported along the mine face 10 and transporting the gyroscope 26 along the mine face 10. The output signal may be used to control the operation of a collection of mine roof supports 13 in such a way as to keep the mine face 10 substantially straight. <IMAGE>

Description

PROFILE MEASUREMENT AND CONTROL OF A MINE FACE This invention relates to a method of measuring the profile of a mine face and to a method of controlling the operation of a collection of mine roof supports in such a way as to keep the mine face substantially straight.

One of the problems in sustaining continuous production on longwall faces, particularly on long thin face sections, is the maintenance of face straightness.

Bends in the face can cause mechanical damage to conveyor furniture and roof supports and can also cause face creep i.e. a migration of the face equipment into the roadway.

A considerable amount of research has been done in the past by British Coal in order to find a suitable method of plotting (measuring) the advance of the face at various points along its length in order to measure the face profile. The objective is to use this information to automatically control the distance advanced during successive cycles in order to bring the face back into line automatically.

Hitherto, the only practical method of measuring face advance has been by using a device called a cord transducer. This device consists of a spool of wire (or wire reinforced cord) in which the wire, when drawn off the spool, drives a potentiometer device via a precision pulley. Wire is drawn from the spool during the advance of the support by anchoring the free end into the waste (or caved area). Then as the support advances the potentiometer records the distance travelled.

This method suffers from the obvious disadvantages that cord breakages are not uncommon, and that the spools themselves need to be reloaded at regular intervals. Also, a cord transducer is typically located on every 10th support so that 15 to 20 such devices may need to be employed on each installation.

According to a first aspect of the present invention there is provided a method of measuring the profile of a mine face, comprising the steps of taking a gyroscope capable of producing an output signal representative of the mine face profile if transported along the mine face and transporting the gyroscope along the mine face.

Preferably, the gyroscope is a vibration gyroscope employing a plurality of piezoelectric ceramic elements.

Preferably, the gyroscope is transported along the mine face by a mineral winning machine, e.g. a shearer. Alternatively, the gyroscope may be transported along the mine face by guide means attached to a face conveyor or by the face conveyor itself.

Preferably, the output signal of the gyroscope is transmitted by a radio transmitter to a receiver which may be located at one end of the mine face.

According to a second aspect of the invention there is provided a method of controlling the operation of a collection of mine roof supports each comprising a roof engageable canopy, a ground engaging base, hydraulic prop means for raising and lowering the canopy relative to the base, and means for advancing the roof support relative to a face conveyor and for advancing the conveyor relative to the roof support, the method comprising the step of employing the output signal produced by the gyroscope in accordance with the method disclosed in the first aspect of the invention to control the roof supports in such a way as to keep the mine face substantially straight.

The invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic plan view showing a face conveyor and a collection of mine roof supports arranged in a row along a face being worked, and Figure 2 is a side view of one of the mine roof supports of Figure 1, on an enlarged scale.

Referring firstly to Figure 1 of the drawings, there is shown therein a coal face 10, a face conveyor 11 extending along the face 10, a mineral winning machine in the form of a coal shearer 12 mounted on the conveyor 11 for movement therealong, and a collection of mine roof supports 13 arranged in a row along the face 10.

As shown in Figure 2 of the drawings, each roof support 13 typically comprises a canopy 14, a shield section 15, a lemniscate linkage 16, a base section comprising two parallel spaced apart pontoon members 17, two front hydraulic props 18 and two rear hydraulic props 19.

The shield section 15 is pivotally connected at one end to one end of the canopy 14, and the lemniscate linkage 16, which includes four links 20, is pivotally connected at one end to the other end of the shield section 15, and at the other end to the pontoon members 17.

The roof support 13 also includes an advancing mechanism which is disposed in the space between the pontoon members 17, and which comprises a relay bar 21, a mounting hook 22 connecting one end of the relay bar to the conveyor 11, and an advancing ram (not shown) pivotally connected at one end to the other end of the relay bar 21 and pivotally connected at its other end to the base section. The roof support 13 also has a sprag 23.

The roof supports 13 are operated by a control system comprising a central computer 24 located at one end of the face being worked and a control unit 25 mounted on each roof support. The computer 24 and the control units 25 are powered by one or more power supplies and operate solenoid actuated valves on the roof supports 13.

A gyroscope 26 capable of producing an output signal representative of the mine face profile if transported along the coal face 10 is mounted on the shearer 12 together with an associated radio transmitter 27, and a receiver 28 is located at one end of the coal face 10 and is connected to the central computer 34.

The gyroscope 26 is a miniature vibration gyroscope employing a plurality of piezoelectric ceramic elements and typically of a type made and sold by Murata under the trade mark GYROSTAR and available from Murata Electronics U.K. Ltd, of Ancells Road, Sleet, Aldershot, Hampshire. These vibration gyroscopes are low cost and have accuracy levels which can provide meaningful position data even at relatively low speed levels. They are therefore able to provide a record of the path travelled by the shearer 12 from one end of the face to the other.

The output signal produced by the gyroscope 26 is transmitted by the transmitter 27 to the receiver 28 and is fed into the central computer 34 to control the roof supports 13 so as to correct for any deviation in the coal face 10 from a straight line and thus keep the coal face 10 substantially straight.

The gyroscope 26 can be transported along the coal face 10 other than by the shearer or other mineral winning machine. For example, it could be transported along the coal face by a guide rail or guide hose attached to the conveyor or by the conveyor itself. In the latter case the gyroscope 26 could be manually loaded onto the conveyor in the tail gate and either manually or automatically removed from the conveyor in the main gate.

Claims

1. A method of measuring the profile of a mine face, comprising the steps of taking a gyroscope capable of producing an output signal representative of the mine face profile if transported along the mine face and transporting the gyroscope along the mine face.

2. A method as claimed in Claim 1, wherein the gyroscope is a vibration gyroscope employing a plurality of piezoelectric ceramic elements.

3. A method as claimed in Claim 1 or 2, wherein the gyroscope is transported along the mine face by a mineral winning machine.

4. A method as claimed in Claim 3, wherein the mineral winning machine is a shearer.

5. A method as claimed in Claim 1 or 2, wherein the gyroscope is transported along the mine face by guide means attached to a face conveyor.

6. A method as claimed in Claim 1 or 2, wherein the gyroscope is transported along the mine face by a face conveyor.

7. A method as claimed in any preceding claim, wherein the output signal of the gyroscope is transmitted by a radio transmitter to a receiver.

8. A method as claimed in Claim 7, wherein the receiver is located at one end of the mine face.

9. A method of controlling the operation of a collection of mine roof supports each comprising a roof engageable canopy, a ground engaging base, hydraulic prop means for raising and lowering the canopy relative to the base, and means for advancing the roof support relative to a face conveyor and for advancing the conveyor relative to the roof support, the method comprising the step of employing the output signal produced by the gyroscope in accordance with the method of any of Claims 1 to 8 to control the roof supports in such a way as to keep the mine face substantially straight.

10. A method of measuring the profile of a mine face, the method being substantially as hereinbefore described with reference to the accompanying drawings.

11. A method of controlling the operation of a collection of mine roof supports, the method being substantially as hereinbefore described with reference to the accompanying drawings.