- Geological conditions,
- Length and depth of mine,
- Layout of tunnel routes, slopes, corners, crossroads & dead ends.
- Heat generating equipment such as electrical substations, mechanical crushers, diesel vehicles.
- External climatic conditions
These hot spots combined with the level of humidity and air pressure variations, can impact the underground miner’s working environment, and compromise equipment operation and life span. Traditional climate monitoring is localized and only approximates overall temperatures along the mine.
An example of the application of a DTS system in the coal industry for underground mine temperature monitoring over 2.5 km is shown in the graph below**. For the Geting underground coal mine shown the goaf (partially or totally mined) areas are monitored as they are considered a probable source of heat build-up and possible spontaneous combustion. Simplicity of installation, strength of the Stainless Steel reinforced fibre optic cable, reliable heat detection, and lower total cost of ownership over long distances were the main benefits for the DTS application.
Distributed Temperature Sensing (DTS) technology using a linear heat detector on a single fibre optic core has been successfully tested and deployed in underground mines.
The DTS system’s capabilities have been proven to exceed conventional mine temperature monitoring point detection systems. The ruggedized fibre optic based system has the capacity to detect heat build-up quickly and localize 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.
- Can use existing fibre optic communications cable, no need for new cable or installation.
- Provides the temperature and its location along the whole cable route.
- Provides mine heat map for personnel and equipment safety,
- Safe to install in hazardous areas (zone 0 and zone 20),
- Is immune to EMI (electromagnetic interference),
- Requires no maintenance,
- The fibre cable is the sensor, no other cabling or field interface devices required.
**Liuyuan Leitao, WeiyubinSunzhihui,Wangchang Liutongyu, Application of distributed optical fiber temperature sensing system based on Raman scattering in coal mine safety monitoring; Shandong Key Lab of Optical Fiber Sensing Technology Laser Institute of Shandong Academy of Sciences Jinan, China 2012