Mining Contract: Adapting Remote Methane Leak Detector (RMLD) to Coal Miner Rescue

Contract Status & Impact

This contract is complete.

No final report was generated by the contractor. If further detail is needed, please send a request to mining@cdc.gov.

Methane monitoring is one of the most fundamental safety practices in underground coal mining. Actions for monitoring methane and dealing with elevated methane levels in active areas are specified in 30 CFR 75.342 and 30 CFR 75.323, respectively. Although the CFR mandates point measurements at the production face of at least 1 foot from the roof, ribs, and face, remote methane detection using laser technology adapted from the natural gas leak detection industry offers the promise of a means to make methane measurements at locations where direct access cannot be made safely. The successful development and use of remote methane devices has significant potential to enhance miner safety.

This research effort explored remote detection of methane using laser-based technology. This approach can be useful as a secondary method for detecting methane at a mine face where the operator must remain under supported roof, and in mine rescue situations. Previous work in this field was halted due to technology limitations, but recent advances in computing power, data acquisition and storage capabilities, range-finder technology, and most significantly, laser-based methane detection capability, have made remote detection a realistic option.

Physical Sciences, Inc., had previously developed a technology to direct a pin-point laser light beam at a distant surface to detect methane accumulations. The attenuation of the beam energy reflected from this surface is related to the amount of methane present along the beam length. As a result of the initial contracting effort, a device using this technology was successfully evaluated in the Office of Mine Safety and Health Research (OMSHR) Safety Research Coal Mine (SRCM), the OMSHR full-scale ventilation test gallery, and in an actual underground coal mine. The lack of a necessary experimental permit issued by the Mine Safety and Health Administration (MSHA), however, significantly limited the range of conditions and locations to which the RMLD could be tested.

Although the contractor was eventually able to obtain an MSHA experimental permit for the RMLD, Physical Sciences, Inc., was unsuccessful in gaining access to an underground mine site in which to conduct more thorough evaluations of the device. However, the contractor was able to deliver a requirements document with key operating specifications, methods of operation, and plans for implementing the use of the RMLD in an underground coal mine environment.

The current RMLD device consists of a large hand-held unit containing the range finder and infrared diode laser connected via a thick cable to a shoulder-supported battery and alarm unit. Not surprisingly, its utility for underground use is limited due to the size and weight of the various components. Recognizing this limitation, Physical Sciences, Inc., worked with Helix, Inc., during the most recent contracting effort to develop sketches of possible prototype designs for the RMLD that would incorporate all optics and electronics into a single, much smaller lightweight unit. The actual construction of a prototype was scheduled for a subsequent contract award.