Objective
Direct communication with the drivers of free-steered vehicles below ground in mines susceptible to firedamp is becoming essential to improved safety. Special communications equipment is to be designed to provide the facilities required. The coded messages to be sent to the drivers are selective calls or alarms. For their part, the drivers must be able to acknowledge calls or send out distress calls. Facilities for speech communication with certain drivers are also desirable.
The project will comprise the design and production of a prototype system, followed by a pilot installation below ground using the equipment developed.
The system, TELSAFE AS (Selective call), will be used in conjunction with WIZCON surveillance software. A prototype intended for a pilot installation in the Provence Group was made by NS TELEMAC, a manufacturer and applicant for a certificate of conformity with requirements for use in gassy mines. The equipment is made up of components already in use in other TELSAFE systems, and newly designed components. The final adjustments and laboratory testing of the system wee carried out at INERIS.
The pilot installation was set up in the Provence Group in October 1994 with a roadway network consisting of 1400m of CERLIL leady feeder.
In the initial test phase, an ERAM set was installed on a vehicle used solely for the purpose of the trials.
In the second test phase, the ERAM control base was set up on a vehicle in normal use. The performance of the system was entirely satisfactory. The staff concerned appreciated the benefits offered by TELSAFE AS.
The bleeper systems available on the market are designed for surface applications. They comprise a transmitting set and portable individual receivers. Such equipment cannot work in underground mines, where electromagnetic waves do not propagate in the same way as above ground. In addition, the purpose of these systems is paging of persons equipped with the receiver and they do not enable such persons, i.e. isolated or roving personnel on board vehicles, to acknowledge calls or send out emergency calls.
The PHONESAFE system in service in French coal mines is intended to permit speech communication between fixed and mobile sets over long distances below ground. The equipment was designed for use in gassy mines. the signals are transmitted through the roadways and workings by means of a leaky coaxial cable, the CERLIL cable, which is fitted at intervals with remotely switched repeater-amplifiers automatically controlled by a central base according to the flow of communications on the network.
A feasibility study (contract ECSC 7258/05/148/03) showed that the same transmission line equipped with two-way repeater-amplifiers would permit simultaneous and independent operation of PHONESAFE and the special selective calling and alarm system which it is proposed to design.
The call/alarm system will consist of a number of specific devices which will have to be designed. Together with the PHONESAFE components, these will make up the entire driver safety communications system.
A central call/alarm base located at the surface will be linked by telephone lines to a transceiver, which will be situated blow ground and connected to the leaky feeder network. The system, fitted with two-way repeater-amplifiers, will convey speech communication and call/alarm signals on two different radiofrequency channels. The call/alarm and speech communication functions can thus be performed independently since their respective radiofrequency signals can be transmitted simultaneously over the same system, either in the same or in opposite directions.
The set carried on board the vehicles will be capable of receiving selective calls and alarms and of transmitting call acknowledgements and distress signals. It will consist essentially of a radiofrequency transceiver connected to a device for coupling to the system feeder, coding and uncoding units for call/alarm messages and a power supply with battery back-up permitting continued operation when the vehicle is stopped.
%Health monitoring for the entire installation will be integrated into the system as an aid to trouble-shooting and maintenance.
Topic(s)
Call for proposal
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60550 Verneuil-en-Halatte
France