Mining Contract: Post-Accident AMS System

Contract Status & Impact

This contract is complete. To receive a copy of the final report, send a request to mining@cdc.gov.

An Atmospheric Monitoring System (AMS) depends on a functioning ventilation system to have fresh-air entries. When the mine fan stops, the mine has 15 minutes to either re-establish the fan or start evacuating all personnel. After 15 minutes, the mine is considered hazardous, and all underground AC mains power must be de-energized, which shuts off external power to the AMS. However, the internal batteries of the AMS remain in place, and these are not intrinsically safe. A paradox to the design of current Atmospheric Monitoring Systems is that at the time monitoring is needed most the system must be shut off.

This work developed and tested an intrinsically safe AMS that can stay operational post-event. The 30 CFR Part 23 compliant system uses power stations with only intrinsically safe outputs. All system components connected to the power stations are intrinsically safe. Using this approach, the mine fan no longer determines when the system is de-energized. In addition, the electrical cables connecting the systems components no longer need to be maintained in any specific location.

The developed system handles combinations of atmospheric monitoring (carbon monoxide, oxygen, methane), personnel tracking, and two-way communications. The incorporation of these components into a single network is critical to rescue efforts in that this approach allows all necessary system to remain operational simultaneously.