Underground coal mine fires pose a serious safety risk to mine workers and can cost mining companies significant losses due to the destruction of equipment and infrastructure.
Once an underground mine fire is ignited it can be very difficult to put out. An example of this is the Centralia mine fire in Pennsylvania that has been burning for over 50 years, damaging environmental and public health. Another example is the Mount Wingen coal seam fire here in Australia which has been burning for 6,000 years.
The causes of underground coal mine fires are difficult to detect early with traditional fire and heat detection technology. These older technologies also require expensive ongoing maintenance and often struggle to perform effectively in dust-filled, rugged mining environments.
In this post, we’ll be discussing the benefits of employing Distributed Temperature Sensing systems to enable constant, reliable and precise environmental monitoring. Environmental monitoring using DTS technology can detect abnormal heat build-up in a mine – avoiding combustion – and improve operating conditions for personnel and equipment.
What Is Environmental Monitoring and Why Does It Matter?
Underground mines can develop significant hot spot areas due to many factors including:
- 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. They can also create spontaneous combustion, leading to underground mine fires.
Traditional climate monitoring is localised and only approximates overall temperatures along the mine. DTS monitoring provides accurate temperature monitoring localised to the nearest 20mm throughout the mine.
Environmental Monitoring Case Study
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, 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 fiber optic cable, reliable heat detection, and lower total cost of ownership over long distances were the main benefits for the DTS application.
A temperature monitoring system that can provide 24×7 monitoring would greatly increase operating safety for the protection of people and fixed assets.
Distributed Temperature Sensing (DTS) technology using a linear heat detector on a single fiber 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 fiber 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.
The Advanced Photonics Australia Solution
Our fibre optic cable Distributed Temperature Sensing system provides the following key features for your underground mine operation:
- 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.
To enquire about a DTS solution for fire avoidance and environmental monitoring at your mine site:Contact Advanced Photonics Australia Today
**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