AU735674B2

AU735674B2 - Underground mine communications

Info

Publication number: AU735674B2
Application number: AU69008/98A
Authority: AU
Inventors: George Kevin Trevitt
Original assignee: HEPONI Pty Ltd
Current assignee: HEPONI Pty Ltd
Priority date: 1997-05-28
Filing date: 1998-05-27
Publication date: 2001-07-12
Anticipated expiration: 2018-05-27
Also published as: AU6900898A

Description

47560 AWT:PFB P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

0 @0 a *0*e 0* a 0 *00* *.o aa 0 Name of Applicant: HEPONI PTY LIMITED Name of inventor(s): George Kevin Trevitt ADDRESS FOR SERVICE

ALTERED

Address for Service: Invention Title: UNDERGROUND MINE COMMUNICATIONS Details of Associated Provisional Applications: P07024 dated 28th May 1997 The following statement is a full description of this invention, including the best method of performing it known to us: 2

TITLE

UNDERGROUND MINE COMMUNICATIONS TECHNICAL FIELD This invention relates to communication and in particular communications underground in mines.

BACKGROUND ART Communication is most important in mines particularly for safety and security reasons. Some form of communication system is generally installed in a mine as mining continues along drives and shafts.

It is usual however that miners and mine equipment is worked some distance o: ahead of the installed communication system and receiving communications from the installed system can be difficult and unreliable. This has serious 0 efficiency and safety implications.

1 5 It is the object of this invention to provide a system whereby communication can be transferred from a coupling point at the extent of the installed system o *within a mine to a mine face which may be some distance ahead of the coupling point.

:One type of installed communication system within a mine is known as a leaky feeder cable. In such a system a coaxial cable having a shield of less than 100% optical coverage is fed with a radio signal at one end and it acts like an aerial along the length of the mine. At any point along the mine then the radio signal transmitted on the coaxial cable can be received. At the mine face, however, the radio signal may not be sufficiently or safely received and it is an object of this invention to provide a repeater system for extending forward the radio signal.

DISCLOSURE OF THE INVENTION In one form therefore although this may not necessarily be the only or broadest form the invention is said to reside in a mine communication arrangement of a type adapted to receive and transmit radio and telephone signals to and from a coupling point to a mine face within a mine, and having a safety power cable extending from the coupling point to the mine face for operation of a machine, the safety power cable being of a type having a plurality of high voltage power conductors, a low voltage pilot cable conductor and a slightly conductive medium around the conductors and cable, the communication arrangement characterised by means to couple the signal to one of the conductors at the coupling point and means to decouple the signal 1 0 from one of the conductors at the machine at the mine face.

In one form of the invention the signal is coupled to one of the conductors by capacitive coupling.

.In an alternative form the signal is coupled to one of the conductors by optoelectronic coupling.

1 5 In a further alternative form the signal is coupled to one of the conductors by inductive coupling.

Preferably the conductor to which the signal is coupled is the pilot cable.

It will be seen that by this means the signal from the coupling point to the machine at the mine face can be coupled such as by capacitive coupling onto 2 0 the pilot cable within the safety cable extending forward to operate the machine and extracted from the pilot cable at the machine by another coupling such as by capacitive coupling. This means that no extra cabling is required in the mine face area and no modifications are needed to the safety power cable.

In one embodiment the means to capacitively couple the signal to the pilot cable within the safety cable may include an aerial to receive a signal from the leaky feeder cable and a transceiver arrangement such as a high frequency transceiver to couple the signal to the pilot cable. Alternatively the means may comprise a telephone connection to a telephone network within the mine or 3 0 any other conductor which may be connected to a signalling apparatus.

The means to decouple the signal at the machine at the mine face may include a transceiver such as a high frequency transceiver which includes a microphone and speaker or alternatively it may include a re-transmission system so that the signals are carried forward to any operator requiring them.

It will be realized that the description of coupling of the signal to the conductor at the coupling point may include the decoupling at that point of a signal from the mine face. Similarly the use of the term decouple in reference to the extraction of the signal from a conductor at the machine may include coupling of a signal onto the conductor at that point.

The uses to which the forward radio or telephone transmission system may be 1 0 applied are for voice communications, remote control of machines, emergency signal transmission, monitoring of operating conditions of the machine or environment or radio transmission in the mine face area.

BRIEF DESCRIPTION OF THE DRAWINGS S• This then generally describes the invention but to assist with understanding 1 5 reference will now be made to the accompanying drawings which show a preferred embodiment of the invention.

In the drawings: FIG 1 shows a general schematic view of a mine with a coupling point and a forward working machine according to one embodiment of this invention, .0 20 FIG 2 shows a construction of a safety cable of the type utilised in the present invention, FIG 3 shows a schematic view of a coupling and decoupling arrangement according to one embodiment of this invention, and FIG 4 shows a schematic circuit diagram of a coupling and decoupling arrangement according to one embodiment of this invention.

BEST MODE FOR CARRYING OUT THE INVENTION Now looking more closely at the drawings it will be seen that the mine generally shown as 1 has a power coupling point generally shown as 2 which is essentially at the forward extent of installed equipment within a mine shaft or tunnel. A drive generally shown as 3 extends forward from the power coupling point to a mine face 4. In the mine face 4 a piece of machinery 6, such as a rock drill, is operating and is driven by a safety power cable 7 extending from a power supply 8 at the coupling point. The power supply 8 at the coupling point receives power through cable 17.

Communications transmissions are provided through a leaky feeder cable which services the coupling point area and a signal transmitted from the leaky feeder cable 10 is received by an aerial 11 and by means of electronic circuitry in high frequency transceiver 9 is capacitively coupled into a pilot cable within the safety cable 7 within the power supply box 8. At the machine 15 6 the capacitive decoupling occurs and the signal is fed into a high frequency transceiver 14 for operation of required machinery such as a loudspeaker 12 and a microphone 13.

Alternatively the signal for the transceiver 9 may be provided by a telephone line 16 installed within the mine.

The safety cable is shown in cross-section in FIG 2. Includes a number of power conductors 20 and a central pilot cable 21 in a carbon and rubber matrix medium 22 with a surrounding shielding 23.

In use if the safety cable is damaged by a rock fall or the like a change in the electrical resistance between the pilot cable and the conductive carbon medium causes a relay to trip which disconnects the power to the safety cable.

This does not, however, prevent the transmission of signals down the pilot cable. Maintenance of communications may be essential in the event of an occurrence such as a rock fall.

In FIG 3 the arrangement is schematically demonstrated.

3 0 The safety cable 7 is plugged at the coupling point end to the power supply box 8 and at the other end is hard wired into the machine 6 or plugged into the socket 33 at the machine 6.

In the power supply box 8 a relay 30 is adapted to disconnect the power supply to the safety cable 7 if a change in current flow occurs between the pilot cable 21 and the conductive medium 22. In the present invention aerial 11 receives a signal which is transferred by wire 31 and capacitor 32 to connect to the pilot cable 21. At the machine end 33 a capacitor 34 and wire extracts the signal and transfers it to a transceiver 36 which may operate a loudspeaker 12 and microphone 13.

1 0 FIG 4 shows a schematic circuit diagram of a coupling and decoupling arrangement according to one embodiment of this invention which makes use of the pilot cable for signal transmission. In this arrangement a first control box is at the head of the installed section of the mine drive. The main power cables are not shown. Transformer 41 provides power to the pilot cable 42 1 5 which is within the safety cable (see FIG 3) and extends forward to a forward control box 44.

Within the first control box 40 a tapping 46 is taken off to a further transformer 47 to supply DC power to a high frequency transceiver 48 via a rectifier circuit 49. Signals are provided from a transceiver interface or telephone connection 2 0 50. The signal are processed in transceiver 48 and the capacitively coupled to the pilot cable 42 via line 51 and capacitor 52. At the forward control box 44 the signal is decoupled through line 55 and capacitor 56 to high frequency transceiver 57. Power for high frequency transceiver 57 is provided by battery 58. Loudspeaker 59 and microphone 60 are connected to high frequency transceiver 57. It will be realised of course that line 51 and capacitor 52 and line 55 and capacitor 56 both act to couple and decouple signals as signals may be passed in both directions.

As discussed earlier as an alternative to an aerial and radio system the communication as per the present invention may operate on a telephone type 3 0 system.

There may be used signals of different characteristics so more than one of the types of uses can occur on the same cable at the same time.

Throughout this specification unless the context requires otherwise, the words 'comprise' and 'include' and variations such as 'comprising' and 'including' will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

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Claims

2. The mine communication arrangement as in Claim 1 wherein the signal is coupled to one of the conductors by capacitive coupling.
3. The mine communication arrangement as in Claim 1 wherein the signal is coupled to one of the conductors by optoelectronic coupling.
4. The mine communication arrangement as in Claim 1 wherein the signal is coupled to one of the conductors by inductive coupling. The mine communication arrangement as in any one preceding claim wherein the conductor to which the signal is coupled is the pilot cable conductor.
6. The mine communication arrangement as in as in any one preceding claim wherein the means to couple the signal to the conductor within the safety cable includes an aerial to receive a signal from a leaky feeder cable and a transceiver arrangement.
7. The mine communication arrangement as in as in any one preceding claim wherein the means to couple the signal to the conductor within the safety cable includes a telephone connection to a telephone network within the mine.
8. The mine communication arrangement as in as in any one preceding claim wherein the means to decouple the signal at the machine at the mine face includes a transceiver arrangement which includes a microphone and speaker.
9. The mine communication arrangement as in as in any one preceding claim wherein the means to decouple the signal at the machine at the mine face includes a re-transmission system so that the radio signals are carried forward to any operator requiring the signal. The mine communication arrangement as in any one preceding claim applied for voice communications, remote control of machines, ~emergency signal transmission, monitoring of operating conditions of a machine or environment or radio transmission in the mine face area. o*oo
11. The mine communication arrangement as in any one preceding claim wherein the a transceiver arrangement is a high frequency transceiver.
12. A mine communication arrangement substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings. Dated this 27th day of May 1998 HEPONI PTY LIMITED By their Patent Attorneys, COLLISON CO.