Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-10 (of 10 Records) |
Query Trace: Srednicki J[original query] |
---|
Cryogenic air supply feasibility for a confined space: Underground refuge alternative case study
Yan L , Yantek DS , DeGennaro CR , Srednicki JR , Lambie B , Carr J . ASME J Heat Mass Transf 2024 146 (3) A breathable air source is required for a confined space such as an underground refuge alternative (RA) when it is occupied. To minimize the risk of suffocation, federal regulations require that mechanisms be provided and procedures be included so that, within the refuge alternative, the oxygen concentration is maintained at levels between 18.5% and 23% for 96 h. The regulation also requires that, during use of the RA, the concentration of carbon dioxide should not exceed 1%, and the concentration of carbon monoxide should not exceed 25 ppm. The National Institute for Occupational Safety and Health (NIOSH) evaluated the cryogenic air supply's ability to provide breathable air for a refuge alternative. A propane smoker was used to simulate human breathing by burning propane gas which will consume O(2) and generate CO(2) and H(2)O. The rate of propane burned at the smoker was controlled to represent the O(2) consumption rate for the breathing of a certain number of people. Two 96-h tests were conducted in a sealed shipping container, which was used as a surrogate for a refuge alternative. While burning propane gas to simulate human oxygen consumption, cryogenic air was provided to the shipping container to determine if the cryogenic air supply would keep the O(2) level above 18.5% and CO(2) level below 1% inside the shipping container as required by the federal regulations pertaining to refuge alternatives. Both of the 96-h tests simulated the breathing of 21 persons. The first test used the oxygen consumption rate (1.32 cu ft of pure oxygen per hour per person) specified in federal regulations, while the second test used the oxygen consumption rate specified by (Bernard et al. 2018, "Estimation of Metabolic Heat Input for Refuge Alternative Thermal Testing and Simulation," Min. Eng., 70(8), pp. 50-54) (0.67 cu ft of pure oxygen per hour per person). The test data shows that during both 96-h tests, the oxygen level was maintained within a 21-23% range, and the CO(2) level was maintained below 1% (0.2-0.45%). The information in this paper could be useful when applying a cryogenic air supply as a breathable air source for an underground refuge alternative or other confined space. [DOI: 10.1115/1.4064062]. |
A new apparatus to measure ELF/VLF electromagnetic noise in coal mines
Zhou Chenming , Srednicki Justin . Min Metall Explor 2022 39 (6) 2343-2349 Ambient electromagnetic (EM) noise (natural or manmade) is a major limiting factor for the design and operation of many electronic devices, including through-the-earth (TTE) communications and tracking systems. Extensive studies on EM noise were conducted by the US Bureau of Mines in the 1970s and 1980s. Changes in the design and operation of electrical equipment since then, however, have resulted in changes in the EM noise environment. This paper reviews past research on surveying EM noise in the extremely low-frequency (ELF) and very-low-frequency (VLF) bands, which are the operating bands for TTE systems, and introduces a new battery-powered, rugged, portable measurement system for surveying EM noise in mining environments. Examples of surveyed EM noise measurement results in and above an active underground coal mine, using the new system, are presented in terms of absolute magnetic field strength levels. A new metric, average noise level (ANL), is introduced to characterize the noise level relative to a particular frequency band for a specific location. It is found that EM noise in mining environments varies significantly with time and location. EM noise levels at frequencies of 30 Hz that shifted from power harmonics (e.g., 90, 150, 210, 270 Hz) are relatively low and their variation with time can be statistically modeled by a Gaussian distribution. The conclusions and findings presented in this paper can help better design and operate TTE communications and tracking systems in underground mines. © 2022, This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply. |
Cryogenic air supply for cooling built-in-place refuge alternatives in hot mine
Yan L , Yantek D , Reyes M , Whisner B , Bickson J , Srednicki J , Damiano N , Bauer E . Min Metall Explor 2020 37 (3) 861-871 Built-in-place (BIP) refuge alternatives (RAs) are designed to provide a secure space for miners who cannot escape during a mine emergency. Heat and humidity buildup within RAs may expose miners to physiological hazards such as heat stress. To minimize the risk of heat stress, Title 30 Code of Federal Regulations (CFR), or 30 CFR, mandates a maximum allowable apparent temperature (AT) for an occupied RA of 35 °C (95 °F) (MSHA 2008 [1]). The National Institute for Occupational Safety and Health (NIOSH) has conducted extensive research on the thermal environment of occupied RAs intended for use in underground coal mines. NIOSH research has demonstrated that a fully occupied BIP RA can exceed the AT limit by > 5.6 °C (10 °F) in mines with elevated mine strata and air temperatures (Bissert et al. 2017 [2]). In this circumstance, an RA cooling system could provide a solution. This paper provides an overview of test methodology and findings as well as guidance on improving the performance of a cryogenic air system prototype by optimizing the flow rate, increasing the tank storage capacity, and improving the efficiency of the heat exchanger of the cryogenic system. This may enable BIP RAs to meet the 35 °C (95 °F) AT limit in mines with elevated temperatures. The information in this paper is useful for RA manufacturers and mines that may choose to implement a cryogenic air system as a heat mitigation strategy. |
Influence of steel mesh on magnetic proximity detection systems: An experimental study
Zhou C , Whisner BG , Carr JL , Srednicki J . Prog Electromagn Res M Pier M 2020 90 89-97 Proximity Detection Systems (PDSs) are used in the mining industry for protecting mine workers from striking, pinning, and crushing injuries when they work in close proximity to heavy machines such as continuous mining machines (CMMs). Currently all PDSs approved by the Mine Safety and Health Administration (MSHA) are magnetic field based systems which can be influenced by the presence of steel wire mesh that is commonly used for supporting roof and ribs in underground coal mines. In this paper, researchers at the National Institute for Occupational Safety and Health (NIOSH) characterized the influence of the mesh on the performance of magnetic PDSs by measuring the magnetic field difference around a CMM caused by the presence of the mesh. The results show that the magnetic fields are generally enhanced by the mesh which causes PDS detection zones to be increased correspondingly. It was discovered that the fields around the joints of two mesh sections have the greatest enhancement and thus deserve more attention. In addition, it was found that the presence of mesh can also cause a variation in the generator current. The experimental results show that the generator current variation and thus the magnetic field change caused by the mesh can be significant (on the order of ten) when the mesh is extremely close to the generator (e.g., less than 1 cm) and is negligible when mesh is relatively far (greater than 0.15 m). The findings in this paper can be used to develop guidelines and best practices to mitigate the influence of mesh on PDSs. |
Underground mine refuge alternatives heat mitigation
Yan L , Yantek D , Lutz T , Yonkey J , Srednicki J . J Therm Sci Eng Appl 2020 12 (2) 021019 In case of an emergency in an underground coal mine, miners who fail to escape from the mine can enter a refuge alternative (RA) for protection from adverse conditions, such as high carbon monoxide levels. One of the main concerns with the use of both portable and built-in-place (BIP) RAs, especially for hot or deep mines, is the interior temperature rise due to the occupants' metabolic heat and the heat released by devices such as the carbon dioxide (CO2) scrubbing system. The humidity within the RA will also increase through occupants' respiration and perspiration and from the chemical reaction within the CO2 scrubbing system. Heat and humidity buildup can subject the occupants to hazardous thermal conditions. To protect RA occupants, Mine Safety and Health Administration regulations mandate a maximum apparent temperature of 95F within an occupied RA. The National Institute for Occupational Safety and Health (NIOSH) tested both an air-conditioned borehole air supply (BAS) and a cryogenic air supply for RAs in the NIOSH Experimental Mine in Bruceton, Pennsylvania. The BAS was tested on a 60-person BIP RA, while the cryogenic air supply was tested on a 30-person BIP RA and a portable 23-person tent-type RA. Multiple tests were conducted with both air supplies to assess their ability to cool RAs. The test results show that the BAS and the cryogenic air supply were able to maintain the apparent temperature within the tested RAs under the 95F limit. The BAS and the cryogenic air supply are potential RA heat mitigation strategies that mines could use to prevent heat/humidity buildup within RAs. |
A test method for evaluating the thermal environment of underground coal mine refuge alternatives
Yantek DS , Yan L , Damiano NW , Reyes MA , Srednicki JR . Int J Min Sci Technol 2019 29 (3) 343-355 Since 2009, the Mine Safety and Health Administration (MSHA) has required mines to install refuge alternatives (RAs) in underground coal mines. One of the biggest concerns with occupied RAs is the possible severity of the resulting thermal environment. In 30 CFR 7.504, the maximum allowable apparent temperature (AT) for an occupied RA is specified as 35 °C (95 °F). Manufacturers must conduct heat/humidity tests to demonstrate that their RAs meet the 35 °C (95 °F) AT limit. For these tests, heat input devices are used to input the metabolic heat of actual miners. A wide variety of test methods, sensors, and heat input devices could be used when conducting such tests. Since 2012, the National Institute for Occupational Safety and Health (NIOSH) has conducted over thirty 96-hour heat/humidity tests on four different RAs. This paper discusses the test equipment and procedures used during these investigations. This information is useful for RA manufacturers conducting RA heat/humidity tests, for other researchers investigating RA heat/humidity buildup, and for those who need to assess the thermal environment of any confined space where people may be trapped or are seeking refuge. |
Electromagnetic interference from personal dust monitors and other electronic devices with proximity detection systems
Noll J , Matetic RJ , Zhou JLC , DuCarme J , Reyes M , Srednicki J . Min Eng 2018 70 (5) 61-68 In April 2016, the U.S. Mine Safety and Health Administration (MSHA) began requiring the use of continuous personal dust monitors to monitor and measure respirable mine dust exposures to underground coal miners. Mines are currently using the PDM3700 personal dust monitor to comply with this regulation. After the PDM3700's implementation, mine operators discovered that it interfered with proximity detection systems, thus exposing miners to potential striking and pinning hazards from continuous mining machines. Besides the PDM3700, other electronic devices were also previously reported to interfere with proximity detection systems. MSHA sought the aid of the U.S. National Institute for Occupational Safety and Health (NIOSH) and mining industry stakeholders to determine how the PDM3700 and some other electronic devices and proximity detection systems interact with each other. Accordingly, NIOSH investigated existing standards, developed test protocols, designed experiments and conducted laboratory evaluations. Some interferences were observed to be caused by electromagnetic interference from some electronic devices, including the PDM3700. Results showed that there was no significant interference when the PDM3700, as well as other electronic devices, and the miner-wearable component of the proximity detection system were separated by distances of 15 cm (6 in.) or greater. In the present study, it was found that the PDM3700 and the personal alarm device needed to be at least 15 cm (6 in.) apart in order for them to be used simultaneously and reduce potential interference. |
Comparative evaluation of light-emitting diode cap lamps with an emphasis on visual performance in mesopic lighting conditions
Reyes MA , Sammarco JJ , Gallagher S , Srednicki JR . IEEE Trans Ind Appl 2014 50 (1) 127-133 Conducted at the National Institute for Occupational Safety and Health's (NIOSH) Office of Mine Safety and Health Research, the experiment described in this paper is part of ongoing mine illumination research designed to explore the benefits of solid-state lighting technologies when applied to the underground mining industry. This experiment involves the comparative evaluation of cap lamps with similar spectral power distributions, focusing on the electrical and battery discharge characteristics, with a secondary objective being the benefits gained through alternative light beam distributions. NIOSH researchers conducted the investigation by comparing three commercially available light-emitting diode cap lamps and an NIOSH prototype cap lamp at varying power settings. Visual performance for the detection of hazards was quantified by recording times of detection for finding rotating targets in the peripheral field of view and objects representing trip and fall hazards on the ground. The NIOSH prototype cap lamp resulted in improvements ranging from 15% to 43% for peripheral motion detection time and 5%-23% for slip, trip, and fall object detection time, respectively, as compared with the referent incandescent cap lamp. 1972-2012 IEEE. |
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. |
A visual warning system to reduce struck-by or pinning accidents involving mobile mining equipment
Sammarco J , Gallagher S , Mayton A , Srednicki J . Appl Ergon 2012 43 (6) 1058-65 This paper describes an experiment to examine whether a visual warning system can improve detection of moving machine hazards that could result in struck-by or pinning accidents. Thirty-six participants, twelve each in one of three age groups, participated in the study. A visual warning system capable of providing four different modes of warning was installed on a continuous mining machine that is used to mine coal. The speed of detecting various machine movements was recorded with and without the visual warning system. The average speed of detection for forward and reverse machine movements was reduced by 75% when using the flashing mode of the visual warning system. This translated to 0.485 m of machine travel for the fast speed condition of 19.8 m/min, which is significant in the context of the confined spaces of a mine. There were no statistically significant differences among age groups in the ability to detect machine movements for the visual warning modes in this study. The visual warning system shows promise as a safety intervention for reducing struck-by or pinning accidents involving continuous mining machines. The methods and results of this study could be applied to other moving machinery used in mining or other industries where moving machinery poses struck-by or pinning hazards. |
- Page last reviewed:Feb 1, 2024
- Page last updated:May 06, 2024
- Content source:
- Powered by CDC PHGKB Infrastructure