Mining Contract: Integration of Sensing Technologies for Post-Event Monitoring of Hazardous Conditions in the Mining Environment
Currently, wireless communications within mines—leaky feeder or mesh/node-based approaches—are normally deployed in frequently travelled areas of underground mines. In addition, carbon monoxide sensors are typically installed in conveyor belt entries. It is not common to provide coverage in lesser traversed, remote areas of a mine. To provide detection of ambient conditions in such areas, a prototype repeater system with sensing modules is proposed that is capable of linking into the existing, hardened communications and tracking system.
Contract Status & Impact
This contract is complete. To receive a copy of the final report, send a request to firstname.lastname@example.org.
To allow for communications in large mines, leaky feeder or node/mesh-based systems have been installed into well-traversed portions of mines, mainly for two-way communications and the tracking of personnel. The amount of coverage provided by these systems differs from mine to mine and system to system. Lesser-traversed and remote areas of mines tend not to be well-covered.
There are several benefits to providing environmental monitoring in less-traversed and remote areas of mines. During a post-accident scenario, remote monitoring of environmental conditions (e.g., gas and temperature levels) can provide intelligence on optimal escape routes, aid in evaluating rescue response options, and expedite re-entry into the mine. Two significant challenges exist for deployment of such monitoring nodes: (1) no wireless infrastructure, and (2) lack of power sources post-accident in mines.
Under this contract, SenSevere, LLC, developed a system that is designed to extend existing wireless infrastructure and sense the requisite environmental parameters. The system included three primary components: (1) a sensing module, (2) repeater modules, and (3) an interface module. The repeater and sensing modules are significant engineering challenges because it is difficult to achieve signal reliability while operating within the limited power budget necessary to ensure requisite lifetime.
This research focused on solving the power consumption issue with two separate approaches: (1) reducing power consumption of components, and (2) implementing complex power-save/wake-up protocols. Reducing power consumption allows the power-on periods to be as efficient as possible and minimize their impact on the power budget, while the complex power-save/wake-up protocols allow for data to be delivered on-demand or as needed. By simultaneously implementing both solutions, the overall power consumption was drastically lowered. After understanding and minimizing the power consumption of the system, the requisite volume of lithium batteries was determined, and a battery box module was designed to ultimately meet all requirements within 30 CFR Part 18.
The final report for this contract contains recommendations for future work in the areas of environmental monitoring system power management, network scaling, and sensor calibration. If proposed future development work results in a mine-worthy monitoring system for remote areas, the contractor would explore commercialization in conjunction with a manufacturing partner. Such commercialization would include submission of the monitoring system to the Mine Safety and Health Administration (MSHA) for use in gassy mines.
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