Conveyors in mines and quarries for heavy material handling are the most important logistics management asset on the site, delivering the raw or product material from the mine excavation right through to shipping.
A fire on a conveyor system can start from multiple sources, including the material being transported itself, right through to overheated components such as drive or idler bearings, or smouldering dusts leading to spontaneous combustion situations.
Why Is Conveyor Fire Protection Important?
Conveyors are one of the highest maintenance costs for a site with frequent (e.g. shift) inspections of drive bearings, idler rollers, conveyor belt condition, chute blockages and spillages. The conveyor belts can span from 1 up to 4 metres in width and travel up to speeds of 5-6 metres per second. It can cost in the vicinity of $1million to replace a 1-2 km length of conveyor belt.
The Guideline for the prevention, early detection and supression of fires in coal mines, issued by the Mine Safety Operations branch of Industry & Investment NSW, states:
“Additional systems should be provided for early real time fire detection, such as early fire detection warning in: single entry development; belt conveyors; gantries; reclaim tunnels”, including “plant condition monitoring systems” and “rapid and reliable environmental monitoring systems to detect fires early”.
After a conveyor fire in 2006, then Queensland chief inspector of coal mines Brian Lyne said Mine operators should review any similar installations at their mines and determine the “availability and effectiveness of early fire warning monitoring”.
The Problem With Conventional Conveyor Fire Protection
Due to the extended length, slopes, corners and inconsistent covering of most conveyors, traditional environmental monitoring has been inefficient. This is impeded further by the speed of the conveyor and the rugged operating conditions.
Because of these restrictions, conventional point heat detectors and aspirating CO gas detectors do not provide the most effective environmental monitoring. Conventional fire detection systems on this scale also incur prohibitive costs for supply, installation, and maintenance. The result has been inadequately performing conveyor fire detection systems, and in most cases no fire detection at all.
Distributed Temperature Sensing: The Best Conveyor Fire Protection Solution
A fire detection system that can address these conveyor operating conditions would greatly increase fire safety for the protection of people, fixed assets, and minimise disruptions to plant production.
Distributed Temperature Sensing (DTS) technology using a resettable linear heat detector on a single fibre optic core has been successfully tested and deployed on underground and surface conveyor systems.
The DTS system’s capabilities have been proven to exceed conventional point or linear (copper wire based) heat detectors, or aspirating CO gas detectors. The ruggedized fibre optic based system has the capacity to detect fires quickly and localise the source to within 0.5 metres. This precision is unaffected by wind and other environmental effects, because not only convective, but also conductive and radiant (infrared) heat is measured by the system.
Our fibre optic cable distributed temperature system (DTS) provides the following key features for the heavy materials handling conveyor system:
- Accredited for fire detection use (flame resistance 750°C for 2 hours, IEC 60331)
- Doesn’t propagate the flame along the cable (IEC60332-3).
- 24×7 remote temperature monitoring of the entire length, for total coverage.
- Provides the actual location of the fire, to remote monitoring control rooms.
- It provides early warning of heat before a flame occurs.
- Can be installed in harsh environments (stainless steel cable sheath with high crush resistance).
- Is immune to EMI (electromagnetic interference).
- Requires no maintenance, after it is installed.
- The fibre cable is the sensor, no other cabling or field interface devices required.
To enquire about a coal conveyor fire protection solution:Contact Advanced Photonics Australia Today