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Mining Contract: Efficiency Improvement Study of Mine Rescue Breathing Apparatus and Development of an Improved Prototype CCBA

Contract #12FED1213314
Start Date7/1/2012
Research Concept

This research will investigate alternative system designs or current system modifications for mine rescue breathing apparatus, to determine the extent of potential efficiency improvements in duration or reduction in size/weight over existing products. The goal is to develop a proof-of-concept demonstrator, produce prototype improved rescue breathing apparatuses, and perform verification testing.

Topic Area

Contract Status & Impact

This contract is ongoing.

This contract was funded as part of an interagency agreement program, which provides a formal means for federal government agencies to share and further technology that could apply to and benefit mine safety and health. OMSHR identifies other government agencies with the knowledge, skills, and abilities relevant to a health and safety gap and works collaboratively with these agencies to identify the type of technology solution desired and to determine specifications for this technology.

Following a catastrophic event, mine workers and rescue teams may be exposed to harmful gases in the mine atmosphere. Breathing air supplies (BAS) technologies are used to isolate the lungs from this atmosphere or provide refuge alternatives where the atmosphere is controlled. Breathing air supplies for underground mining refer to a range of devices and systems that offer respiratory protection to miners in the event of an emergency. Some examples of BAS are self-contained self-rescuers (SCSRs), closed-circuit oxygen breathing apparatus (CCBAs), and gas supplies for refuge alternatives. Advanced BAS technology could improve a mine worker’s chances of surviving a mine disaster.

The NIOSH-certified CCBA currently used for mine rescue is a semi-closed type device that contains an oxygen source, a constant mass metering system in conjunction with a demand valve for injection of breathing gas, and an integral chemical scrubber to remove carbon dioxide. With this type of design, oxygen is added at a preset rate not less than 1.5 liters per minute regardless of the user’s actual breathing rate, up to activation of the demand valve. Once the demand valve is activated, gas is added as required by the user. At low breathing rates, the set gas injection rate causes inefficiencies and waste. If that rate could be tied to the user's breathing rate throughout all conditions, or electronically controlled, a savings in gas could be realized and the cylinder could be made smaller and less bulky or the duration of the CCBA could be extended.

Under this contract, Naval Sea Systems Command will adapt an existing mathematical model followed by the production of a proof-of-concept CCBA, then develop a field-capable prototype suitable for human testing. A field-capable prototype is defined as a prototype that is able to be tested in a person-worn configuration, but is not a production-grade prototype. A field-capable unit is meant for feasibility and exploratory testing to help make program decisions, and is not as robust as a production-grade unit would be.

The final report produced from this research will include comparisons between the field-capable prototype and the original mine rescue CCBA. Recommendations for developing an improved commercial mine rescue CCBA will also be included in this report.

As of 2014, benchtop test results had been obtained and the CCBA prototype was being prepared for manned testing.