Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-6 (of 6 Records) |
Query Trace: Homce G[original query] |
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Refuge alternatives relief valve testing and design with updated test stand
Lutz TJ , Bissert PT , Homce GT , Yonkey JA . Min Eng 2018 70 (3) 46-50 Underground refuge alternatives require an air source to supply breathable air to the occupants. This requires pressure relief valves to prevent unsafe pressures from building up within the refuge alternative. The U.S. Mine Safety and Health Administration (MSHA) mandates that pressure relief valves prevent pressure from exceeding 1.25 kPa (0.18 psi), or as specified by the manufacturer, above mine atmospheric pressure when a fan or compressor is used for the air supply. The U.S. National Institute for Occupational Safety and Health (NIOSH) tested a variety of pressure relief valves using an instrumented test fixture consisting of data acquisition equipment, a centrifugal blower, ductwork and various sensors to determine if the subject pressure relief valves meet the MSHA requirement. Relief pressures and flow characteristics, including opening pressure and flow rate, were measured for five different pressure relief valves under a variety of conditions. The subject pressure relief valves included two off-the-shelf modified check valves, two check valves used in MSHA-approved built-in-place refuge alternatives, and a commercially available valve that was designed for a steel refuge alternative and is currently being used in some built-in-place refuge alternatives. The test results showed relief pressures ranging from 0.20 to 1.53 kPa (0.03 to 0.22 psi) and flow rates up to 19.3 m3/min (683 scfm). As tested, some of the pressure relief valves did not meet the 1.25 kPa (0.18 psi) relief specification. |
Refuge alternatives relief valve testing and design
Lutz TJ , Bissert PT , Homce GT , Yonkey JA . Min Eng 2016 68 (10) 55-59 The U.S. National Institute for Occupational Safety and Health (NIOSH) has been researching refuge alternatives (RAs) since 2007. RAs typically have built-in pressure relief valves (PRVs) to prevent the unit from reaching unsafe pressures. The U.S. Mine Safety and Health Administration requires that these valves vent the chamber at a maximum pressure of 1.25 kPa (0.18 psi, 5.0 in. H2O), or as specified by the manufacturer, above mine atmospheric pressure in the RA. To facilitate PRV testing, an instrumented benchtop test fixture was developed using an off-the-shelf centrifugal blower and ductwork. Relief pressures and flow characteristics were measured for three units: (1) a modified polyvinyl chloride check valve, (2) an off-the-shelf brass/cast-iron butterfly check valve and (3) a commercially available valve that was designed specifically for one manufacturer's steel prefabricated RAs and had been adapted for use in one mine operator's built-in-place RA. PRVs used in tent-style RAs were not investigated. The units were tested with different modifications and configurations in order to check compliance with Title 30 Code of Federal Regulations, or 30 CFR, regulations. The commercially available relief valve did not meet the 30 CFR relief pressure specification but may meet the manufacturer's specification. Alternative valve designs were modified to meet the 30 CFR relief pressure specification, but all valve designs will need further design research to examine survivability in the event of a 103 kPa (15.0 psi) impulse overpressure during a disaster. |
A review of underground coal mine emergency communications and tracking system installations
Damiano N , Homce G , Jacksha R . Coal Age 2014 119 (11) 34-35 The 2006 Mine Improvement and New Emergency Response Act of 2006 (MINER Act) required all underground coal mines in the U.S. to have a plan to provide post-accident communication and electronic tracking for any mine workers trapped underground. | In response, post-accident communications and electronic tracking (emergency CT) technologies designed to meet MINER Act requirements have been developed by various manufacturers and approved for permissibility by the Mine Safety and Health Administration (MSHA), meaning they may be used safely in coal mines that may have gassy or dust-laden atmospheres. As a result, more than a dozen different emergency CT systems have become available for U.S. underground coal mining. | The National Institute for Occupational Safety and Health (NIOSH) recently conducted a review of the latest MSHA-approved Emergency Response Plans (ERPs) for each active underground coal mine on file as of February 2014 to identify and characterize the types of emergency CT systems installed. This review pertains only to CT systems installed underground for emergency purposes, and does not include any CT systems installed or used for non-emergency situations, such as communications for everyday operations. |
Electrical injuries in the US mining industry, 2000-2009
Homce GT , Cawley JC . Trans Soc Min Metall Explor Inc 2013 34 367-375 The U.S. National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) conducted a study of mining industry electrical injuries reported to the U.S. Mine Safety and Health Administration (MSHA) for the years 2000 to 2009. The findings of that study are detailed in this paper, and serve to characterize the circumstances surrounding electrical injuries and identify causal factors. The study included three tasks: 1) a direct review of mining industry occupational injury data compiled by MSHA, 2) interpretation of the narrative descriptions available for the injuries (from MSHA data) and 3) a separate examination of fatal electrical injuries. Eight-hundred sixty-five electrical injuries were reported during the 10-year period studied, with 39 of those being fatalities. This makes electrical injuries disproportionately fatal with respect to most other types of injuries in mining. Electrical injury rates were higher in coal mining than noncoal mining and, within the coal sector, rates were higher in underground operations than in surface operations. Of the 865 total cases, electrical and machine maintenance or repair activities were involved in 580 (69%), and electricians and mechanics were injured in 362 cases (42%). Of the 39 fatal electrical injuries, 27 (69%) involved electrical maintenance or repair work, and in 21 of these 27 cases, the failure to de-energize, lock-out and tag the circuit was the cause or a contributing factor. Also, contractor employees had a much greater chance of an electrical injury being fatal than did mine operator employees. The top three root causes for fatal electrical injuries were 1) no or inadequate lock-out and tagging, 2) failure of power system components and 3) contact of overhead electrical power lines by mobile equipment. |
NIOSH-sponsored research in through-the-earth communications for mines: a status report
Yenchek MR , Homce GT , Damiano NW , Srednicki JR . IEEE Trans Ind Appl 2012 48 (5) 1700-1707 This paper presents the results of recent contractual research sponsored by the National Institute for Occupational Safety and Health that aimed at demonstrating the feasibility of through-the-earth (TTE) wireless communication in mining. TTE systems, developed by five different contractors, are discussed with a focus on technical approach, prototype hardware, and field test results. System features include both magnetic and electric field sensing, loop and line antennas, digital and analog processing, noise filtering and cancelation, and direction finding. The systems were demonstrated at commercial mine sites. The results of these tests are characterized by transmission range and power levels. This paper concludes with a discussion of issues that remain to be resolved as TTE communications are implemented. These include text versus voice format, acceptable time delays, portability, ease of deployment, an interface with existing communications systems, permissibility, and the effect of geological variations. |
Understanding and quantifying arc flash hazards in the mining industry
Homce GT , Cawley JC . IEEE Trans Ind Appl 2011 47 (6) 2437-2444 Arc flash generally refers to the dangerous exposure to thermal energy released by an arcing fault on an electrical power system, and in recent years, arc flash hazards have become a prominent safety issue in many industries. This problem, however, has not been effectively addressed in the mining industry. Mine Safety and Health Administration (MSHA) data for the period 1990 through 2001 attribute 836 injuries to "noncontact electric arc burns," making them the most common cause of electrical injury in mining. This paper presents results from several elements of a recent National Institute for Occupational Safety and Health study of arc flash hazards in mining and provides information and recommendations that can help reduce these injuries. The characteristics of past arc flash injuries in mining are first outlined, such as the electrical components and work activities involved (based on MSHA data). This is followed by a review of important concepts and terminology needed to understand this hazard. Next, methods for identifying, measuring, and managing arc flash hazards on a power system are covered, with emphasis on recommendations found in NFPA 70E, Standard for Electrical Safety in the Workplace. Finally, results are presented from a detailed arc flash hazard analysis performed on a sample mine electrical power system using IEEE 1584-2004a, focusing on components and locations presenting severe hazards, as well as engineering solutions for reducing the risk to personnel. |
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