Mining Contract: Communication and Hazard Monitoring in Bleeders and Remote Workings
The overall objective of this project is to extend communication and hazard monitoring into bleeders or other remote workings in an active underground coal mine. Longwall bleeders are designed to ventilate the gob gas from mined out panels until an entire ventilation district can be permanently sealed. These areas must be inspected weekly by a certified miner to ensure that the bleeder entries are adequately diluting any methane and moving the methane-air mixture, other gases and dusts to the surface of the mine. The miner must also ensure that the entries are free of obstructions such as roof falls and standing water. The results of the examination must be recorded in a book. The report must include any hazardous condition found, the corrective action taken and the results of all atmospheric measurements. The reporting cannot occur until the certified miner returns from walking the bleeders, a multi-hour process during which the miner has no ability to communicate with anyone.
Contract Status & Impact
This contract is complete. To receive a copy of the final report, send a request to OMSHR@cdc.gov.
Technologies to remotely monitor conditions in bleeders or enable communications between a miner inspecting the area and others do not currently exist and could result in more timely knowledge of, and response to, unusual conditions. Additionally, these technologies would also improve the safety of the otherwise isolated miner conducting the inspection.
This contract research tested how medium frequency could be used in remote areas of an underground coal mine to give voice communication and sensor information. The contractor conducted a demonstration of the deliverables at the Safety Research Coal Mine (SRCM) in Pittsburgh, PA. The tests focused on monitoring carbon dioxide and methane underground while maintaining voice communication with the mine operations center.
Based on products approved as permissible by the Mine Safety and Health Administration (MSHA), modified versions of the DRUM 100P Portable Medium Frequency Radio and the DRUM TTR-100 Tracking Tag Receiver were used to accomplish this demonstration. The DRUM 100P was redesigned to make the device able to be worn on a miner’s belt as opposed to being carried. The TTR-100, which already passes tracking data, was modified to add a gas sensor. None of the modified equipment used was MSHA-approved, but the research concept was to demonstrate products that could potentially be made permissible.
Redesigning existing medium frequency communications and tracking products allowed the contractor to evaluate the performance of these technology adaptations for use in an underground coal mine. Some of the areas tested did not have a defined infrastructure but they had many conductors in them to serve as a path out of the mine. Prior testing has shown that medium frequency signals can travel several miles underground provided there are conductors present.
The completed work resulted in a successful redesign of a medium frequency miner tracker incorporating a two gas (methane and carbon dioxide) sensor. This research also produced a belt wearable medium frequency radio. The system was successfully demonstrated in an underground coal mine. If commercialized, these accomplishments will provide miners with communications while they are inspecting remote mine areas. These accomplishments may also permit mine operators to monitor the atmosphere in remote mine areas in-between the inspections.