A Decoupled Multi-Component IoT Architecture for Enhanced Safety Monitoring and Alerting in Subterranean Coal Mines

Abstract

The coal mining industry continues to deal with methane exposure, the lack of adequate safety precautions, and the deaths of workers. Digital safety and monitoring solutions have suffered from the lack of dependable communication systems. In contrast to other solutions that work to overcome this silo problem, this research work proposes to develop an integrated and modular design. The Sensor Unit measures and transmits the gas/flame temperature and humidity levels, the miners’ Smart Jackets issue and SOS (the international Morse code distress signal) alert and distress calls and the Control Unit collates, synchronizes with the cloud, and retrieves information. The system is NRF24L01 powered and utilizes wireless network solutions that work without the need for an underground internet that had to be built beforehand. The system closes the response time gap to below 350 milliseconds (ms) on end-to-end notifications in Detect and Alert systems with a 145 ± 22 ms notification period from Sensor Unit to Control, and 175 ± 28 ms for Control and Smart Jacket creation. There is system communication for all underground line of sight communication range of 112 ± 5 meters (m) and undocumented coverage of 38 ± 4 m under + 2 structural walls. The systems construction and modular design provide no single failure risk. Sensor Units registered methane concentrations of slightly more than 1%, while 98% of alerts were received by miners in under a quarter of a second. These figures show that the system is scalable, cost-efficient, and able to improve miner safety, with a 98% success rate identifying and warning of threats before they can escalate. Further, the system is ideally suited to be deployed in extremely dangerous areas of mining that have little or no infrastructure. This offers a significant advantage over outmoded safety systems, which trust on communication.