Fibre optic conveyor monitoring system

Abstract

Transporting coal by means of conveyor belts is common in Australian underground coal mines. Major conveyor beltnrelated mining incidents are now relatively infrequent as a result of recent improvements in engineering standards and the use of fire-resistant materials. However, conveyor belts are still a potential cause of personal and structural damage. In addition, any unexpected breakdown of rolling components or failure of belts creates a significant interruption to production, which is a major concern for operators, who are responsible for achieving optimum mining production. This project aimed to develop a fibre opticnbased distributed temperature sensing (DTS) system to monitor the temperature change of malfunction idlers for heavy-duty conveyor belts in underground coal mines. Specifically, the objective of the project was to investigate various installation options for fibre-optic cable along the conveyor belt in order to identify the most effective design. The project was consisted of site trials and laboratory experiments to examine the performance of the DTS system for different cable installation designs and to characterise the behaviour of the DTS system. The results of the site trials and laboratory experiments proved that the fibre opticnbased DTS system is a suitable monitoring system for conveyor belts that can accurately and in real-time identify the faulty idlers that generate heat. The location of the fibre-optic cable with respect to the heated idler plays an important role in the sensitivity and reliability of such a monitoring system. Conduction heat transfer was the only means of heat transfer by which the temperature rise of the faulty idler could be sensed. The fibre-optic cable should be attached to the frame of the idler and as close as possible to the bearing without interfering with the conveyor operation and maintenance. There was a trade-off between the accuracy and response time of the temperature measurements, and the simplicity of the fibre-optic cable installation. The results of the Kestrel North coal mine test proved that the DTS monitoring system is able to provide a real-time temperature profile of the conveyor belt structure and the surrounding area so that the operator can observe the roadway temperature conditions and make critical decisions in serious situations.