The mining method of coal mine can be divided into open-pit mining and underground mining. Although the open-pit mining method is more economic and safe, it has limited resources and low output. The underground mining method can reach the coal mine far away from the surface. Due to the distribution characteristics of coal resources in China, the coal production in China mainly comes from underground mining, and the opencast coal mines only account for 7.5% of the total. In 2005, China's coal output was 2.19 billion tons, while the output of open-pit coal mine was less than 100 million tons. Although underground mining seems to have a high output, there are many hidden dangers due to the impact of the terrain and environment. If the explosion of gas and dust causes the collapse of the mine, the fire and flood in the pit cause the staff to be blocked. In these accidents, the death rate of people in our country is quite high, which is not only related to the safety precautions and facilities of many mine sites, but also related to the failure to take effective and correct rescue actions in time after the mine accidents. As many accidents are inevitable, how to take the right rescue action in the first time after the accident is very important to reduce the death rate.

Advantages of the system:

1、Linear restore, intelligent pattern recognition

When the system detects the vibration signal, the disturbance signal or the actual knocking signal of the trapped personnel can be identified through the linear reduction and behavior analysis of the light wave waveform.  

2、High positioning accuracy, no false alarm and less false alarm

The optical fiber is very sensitive to the change of the external environment, such as the change of temperature, vibration, the change of the position of the optical fiber attachment, etc. For the optical fiber sensing technology based on interference principle, the most serious consequence of polarization change is that the system is in a very insensitive working state, or the system can not achieve effective interference. Therefore, the effective solution to the problem of temperature and polarization sensitivity of optical fiber is the basis of obtaining stable and reliable system. The system technology solves the problem of interference signal stability caused by the change of environment temperature and polarization from the principle of optical path. The system has good reliability and stability.

3、High positioning accuracy

The vibration detection method based on the principle of Φ - OTDR is used to measure the multi-point knocking vibration of the distributed optical fiber sensor, with high sensitivity and long distance distributed measurement, and the positioning accuracy can be within 30 m.。

4、Convenient construction, simple maintenance and strong concealment

The armored communication optical cable is used for personnel positioning system after mine accident, which is convenient in construction, low in cost and simple in application.

5、Long service life and low maintenance cost

The outdoor life of the optical cable is 20 years. The whole system has strong service life and stability, and low maintenance cost.

6、Multipoint detection

    Compared with other detection technologies, it can realize the simultaneous positioning of multi-point personnel and has multi-point measurement function.

Technical features:

    Based on the distributed optical fiber vibration sensing technology, the system has the same test results for the same point of vibration, and the error can be controlled within 30 meters. For multi-point simultaneous rescue, the system can also accurately identify it and locate the location information of all rescue points. The location error is basically independent of the number of rescue points. However, with the increase of the number of rescue points, the possibility of knock overlapping is also increased. From this point, for the signal of simultaneous rescue, the system has the maximum recognizable number. And when there are many disturbance points, the proportion of the effective data of each disturbance point decreases, the peak value decreases, and the error data may overlap, so the proportion decrease is smaller than the effective data. In order to distinguish the effective data and error data, the number of requests for help should not be too much. Generally speaking, the rescue monitoring system can meet the requirements of locating the survivors when the coal mine accident occurs. The system is simple in structure, easy to install and debug. It only needs one optical fiber to realize the distributed monitoring of the whole tunnel, and can work stably and normally in various tunnel environments. Many of its technical advantages are incomparable to other similar equipment.

performance index

1、Laser class：Class IIIb

2、Light source wavelength：1310nm

3、Maximum output power：5mW

4、24-hour output change rate：less than 1%

5、Connector：FC/APC

6、Power supply：AC220V/50 Hz

7、UPS power supply：rated voltage range ± 1%, frequency variation range ± 0.2hz