Evaluation of contamination ingress for built-in-place refuge alternatives.
Lutz T; Noll J; Yan L
Vision, innovation and identity: step change for a sustainable future, 2018 SME annual conference & expo and 91st annual meeting of the SME-MN section, February 25-28, 2018, Minneapolis, Minnesota. Red Hook, NY: Curran Associates, Inc., 2018 Jun; :232-234
Mine disasters, such as fires and explosions, can create a hazardous atmosphere due to the generation of carbon monoxide (CO). After a mine disaster, contaminated mine air can enter the refuge alternative (RA) as miners enter. Most built-in-place (BIP) RAs use an air delivery system to provide an unlimited supply of breathable air through a borehole which also serves to purge contaminants. In order to determine what levels of contaminants enter the RA, researchers from the National Institute for Occupational Safety and Health (NIOSH) conducted testing in NIOSH's Pittsburgh Experimental Mine using groups of 5, 15, and 30 subjects entering the RA. The experiment used sulfur hexafluoride (SF6) as a tracer gas that was released into the air outside of the BIP RA to establish a uniform concentration. After the human subjects entered the BIP RA, the SF6 levels inside the RA were measured to quantify how much of the tracer gas entered the BIP RA. In tests conducted while the borehole air supply was left off as test subjects entered, interior contaminant levels were less than 3% of the exterior concentration. In tests conducted with the borehole air supply activated as test subjects entered, the interior contaminant levels were measured at less than 2% of the exterior concentration. Considering a mine disaster can result in 10,000 ppm of CO in the mine atmosphere, these percentages indicate that unhealthy CO concentrations that may lead to headaches, dizziness, and loss of judgement can occur in a BIP RA. This information will help mines make decisions concerning air locks, air delivery systems and a determination if purging mechanisms are necessary.
Mining; Mining-industry; Miners; Mine safety; Humans; Refuge chambers; Emergency equipment; Work environment; Emergency shelters; Mine disasters; Air contamination; Breathing; Boreholes; Sulfur hexafluoride; Gases; Toxic gases; Air analysis; Air cleaning; Air purifiers; Air quality; Laboratory testing
T. Lutz, NIOSH, Pittsburgh, PA
Vision, innovation and identity: step change for a sustainable future, 2018 SME annual conference & expo and 91st annual meeting of the SME-MN section, February 25-28, 2018, Minneapolis, Minnesota