Last data update: Jun 17, 2024. (Total: 47034 publications since 2009)
Records 1-10 (of 10 Records) |
Query Trace: Rubinstein EN [original query] |
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Equivalency of PDM3700 and PDM3600 dust monitors
Tuchman DP , Mischler SE , Cauda EG , Colinet JF , Rubinstein EN . Min Metall Explor 2024 The PDM3600 and PDM3700 are two closely related person-wearable dust monitors manufactured by Thermo Fisher Scientific. Both are based on tapered element oscillating microbalance technology and provide nearly real-time, mass-based readings of respirable dust concentrations. From a monitoring perspective, the primary difference between the models is the PDM3600 has an integrated cap lamp with attached inlet, while the PDM3700 has no cap lamp and a revised inlet attaches to the worker’s lapel. Using coals of varied origin and employing a wide range of concentrations, side-by-side measurements from these instruments were collected under controlled laboratory conditions and then compared. By use of ordinary least squares and weighted least squares regression methods, followed by mixed model analysis, results suggest there is no statistically significant or practical difference in instrument performance. The two monitors are equivalent for the field dust concentration measurements for which they were designed. © This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply 2024. |
Implications of shale gas well integrity failure near a longwall mine under shallow cover
Ajayi KM , Khademian Z , Schatzel SJ , Rubinstein EN . Min Metall Explor 2023 This study simulates the impact of a shale gas well casing breach near a longwall mine. Field studies are conducted to measure mining-induced permeability changes over the abutment pillar of a longwall mine, and a geomechanical model is developed in 3DEC, a three-dimensional numerical modeling code, to predict the aperture of fractures in the overburden at the study site. The predicted aperture values are used to determine mining-induced permeabilities and the results are compared with the field measurements. These aperture values are provided as inputs into fracture flow code (FFC), which generates a stochastic discrete fracture network (DFN) model for the study site and predicts the potential shale gas flow to the mine. Results from 100 DFN realizations are statistically analyzed using the bootstrapping method to compensate for notable variation in fracture geometry. The results show a significant difference between the gas inflow for nearby panels due to increase in the induced permeability during mining of the second panel. The average gas flow to the mine was calculated as 4.72×10−2 m3/s (49 cfm) for a hypothetical breach at the Sewickley horizon during the first panel mining, 8.97×10−3 m3/s (19 cfm) for a hypothetical breach at the Uniontown horizon during the first panel mining, 2.16×10−1 m3/s (458 cfm) for a hypothetical breach at the Sewickley horizon during the second panel mining, and 8.07×10−2 m3/s (171 cfm) for a hypothetical breach at the Uniontown horizon during the second panel mining. Depending on the mine ventilation system, this could result in methane concentrations exceeding regulatory limits. Hence, these findings provide insights into the potential risk of an unconventional gas well casing breach near a longwall mine under shallow cover. © 2023, This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply. |
Recognition of illuminated coloured markers that designate primary and secondary mine escapeways
Sammarco JJ , Demich B , Macdonald BD , Rubinstein EN , Martell M . Light Res Technol 2020 52 (8) 959-975 It is critical for the safety of miners to be able to escape, unaided, during a mine emergency. Self-escape is challenging in the presence of smoke that can occur during a mine emergency. To assist self-escape, coloured markers in underground mines designate the primary/secondary escapeways, but no universal colour code exists. Ten participants were tested to recognize the colour and designation (primary/secondary) of fluorescent yellow–green (FYG), yellow (Y), white (W) and green (G) escapeway markers in both a clear and smoked-filled environment. The overall misidentification rate for all colours was 1.9% and 18.1%, respectively, in clear and smoke conditions. FYG had the highest misidentification percentage for both conditions. For the marker designation tests, participants were most accurate in clear conditions (100.0%) for the FYG + W, Y + G, G + W and W + FYG combinations, and least accurate (89.6%) for the Y + FYG combination, while for smoke conditions participants were most accurate for the G + Y combination (95.8%). The overall effect of colour combination was significant, indicating that the colour combination for primary/secondary recognition is a significant factor where the G + Y combination was best. It can be inferred from these data that the colour combination is an important factor in participants’ ability to recognize primary/secondary escapeway markers in smoke conditions. |
Performance comparison of four portable FTIR instruments for direct-on-filter measurement of respirable crystalline silica
Ashley EL , Cauda E , Chubb LG , Tuchman DP , Rubinstein EN . Ann Work Expo Health 2020 64 (5) 536-546 Exposure to dusts containing respirable crystalline silica is a recognized hazard affecting various occupational groups such as miners. Inhalation of respirable crystalline silica can lead to silicosis, which is a potentially fatal lung disease. Currently, miners' exposure to respirable crystalline silica is assessed by collecting filter samples that are sent for laboratory analysis. A more timely field-based silica monitoring method using direct-on-filter (DoF) analysis is being developed by researchers at the National Institute for Occupational Safety and Health (NIOSH) to provide mine operators with the option to evaluate miners' exposure at the mine. This field-based silica monitoring technique involves the use of portable Fourier transform infrared (FTIR) instruments. As a step in the development of this new analytical technique, four commercially available portable FTIR instruments were evaluated for their ability to provide reproducible measurements from filter samples containing respirable crystalline silica. Reported testing indicates that measurements varied within +/-4.1% between instruments for filter samples that contained high-purity respirable crystalline silica. Measurements varied within +/-3.0% between instruments for filter samples that contained varying mineral composition. Filter samples were repeatedly analyzed by the same instrument over short and extended periods of time, and mean coefficients of variation did not exceed +/-1.6 and +/-2.4%, respectively. Mixed model analysis revealed that there was no statistically significant (P < 0.05) change in average measurements made over an extended period of time for all instruments. Results suggest that each of the four FTIR instruments evaluated in this study were able to generate precise and reproducible DoF analysis results of respirable dust samples. |
LED area lighting to reduce glare for roof bolter operators
Sammarco JJ , Mayton AG , Rubinstein EN . Min Metall Explor 2020 37 (3) 851-860 Researchers from the National Institute for Occupational Safety and Health (NIOSH) developed a light-emitting diode (LED) area luminaire called the Saturn and conducted a laboratory study using a Fletcher High Dual-boom Mast Feed (HDDR) roof bolting machine. The Saturn luminaire was designed to (1) enhance floor illumination to enable better detection of trip hazards in the interior spaces of a roof bolter and (2) reduce glare that has typically been an issue of concern on roof bolters. This paper reports on the results of achieving the second objective. The existing roof bolter lighting was the baseline and was compared with three versions of the Saturn luminaire relative to light intensity (100%, 75%, and 50%). Discomfort and disability glare data were obtained from 30 participants that comprised three age groups. Discomfort glare perceptions were obtained using the De Boer rating scale, and disability glare was quantified by using Mars Letter Contrast Sensitivity tests. Discomfort glare was reduced at least 3 levels with all Saturn versions. Also, a predictive model was used to estimate discomfort glare, and the results were similar. Disability glare was the least for the Saturn’s 50% intensity, and all Saturn versions had significantly less disability glare than with the baseline lighting. Veiling luminance was calculated and used as another indicator of disability glare. Veiling luminance was 28 to 42 times greater with the baseline lighting as compared with that of the Saturn lighting. Lastly, visibility levels were calculated. The Saturn versions were 4 to 6.5 times better in terms of visibility level. |
Performance comparison of real-time light scattering dust monitors across dust types and humidity levels
Patts JR , Tuchman DP , Rubinstein EN , Cauda EG , Cecala AB . Min Metall Explor 2019 36 (4) 741-749 Video techniques for monitoring exposure, such as NIOSH’s “Helmet-CAM,” employ both real-time dust monitors and mobile video cameras to assess workers’ respirable dust exposures. Many real-time personally worn dust monitors utilize light scattering sensing elements, which are subject to measurement biases as a function of dust type (size, composition, shape factor) and environmental conditions such as relative humidity. These biased and inaccurate dust measurements impair the monitor’s ability to properly represent actual respirable dust concentrations. In the testing described, instrument mass concentration data was collected using three different types of commonly used commercial off-the-shelf personal dust monitors and compared to a reference standard. This testing was performed in a calm air (Marple) dust chamber in which three units of each make and model (for a total of nine monitors) were used for each test. Equivalency factors (EF, a multiplier to match the Thermo TEOM 1400a reference instrument) ranged between 0.746 and 1.879 across all dusts and environmental conditions tested, and between 0.821 and 1.519 on the ISO test dust. |
Testing a revised inlet for the personal dust monitor
Mischler SE , Tuchman DP , Cauda EG , Colinet JF , Rubinstein EN . J Occup Environ Hyg 2019 16 (3) 1-8 A person-wearable dust monitor that provides nearly real-time, mass-based readings of respirable dust was developed for use in underground coal mines. This personal dust monitor (PDM) combined dust sampling instrumentation with a cap lamp (and battery) into one belt-wearable unit, with the air inlet mounted on the cap lamp. However, obsolescence of belt-carried cap lamp and batteries in coal mining ensued and led end users to request that the cap lamp and battery be removed from the PDM. Removal of these components necessitated the design of a new air inlet to be worn on the miner's lapel. The revised inlet was tested for dust collection equivalency against the original cap-mounted inlet design. Using calculated inlet respirable fractions and measured dust mass collection, the performance of the two inlets is shown to be similar. The new inlet requires a 1.02 factor for converting dust masses obtained from it to equivalent masses collected from the original inlet. |
LED lighting for improving trip object detection for a walk-thru roof bolter
Sammarco JJ , Macdonald BD , Demich B , Rubinstein EN , Martell MJ . Light Res Technol 2018 51 (5) 725-741 Proper lighting plays a critical role in enabling miners to detect hazards when operating a roof bolter, one of the most dangerous mining machines to operate; however, there has not been any lighting research to address the walk-thru type of roof bolter commonly used today. To address this, the Saturn light was designed to directly address walk-thru roof bolter safety by improving trip hazard illumination. The visual performances of 30 participants that comprised three age groups were quantified by measuring each participant's visual performance in detecting trip objects positioned on the two floor locations within the machine's interior working space. The lighting conditions were the existing compact fluorescent lights (CFLs) and the Saturn LED area light developed by NIOSH researchers. Three intensities of the Saturn lights were used, 100%, 75%, and 50%, all of which resulted in better visual performance, and up to a 48% reduction in average trip detection time compared to the CFL. For the Saturn trip object miss rates were <0.5% for all age groups in contrast to the CFL, which ranged between 32.5% for the youngest group and 50.4% for the oldest group. |
An analysis of roof bolter fatalities and injuries in U.S. mining
Sammarco JJ , Podlesny A , Rubinstein EN , Demich B . Trans Soc Min Metall Explor Inc 2016 340 (1) 11-20 Roof bolting typically follows the extraction of a commodity to help keep the roof from collapsing. During 2004 to 2013, roof bolter operators had the highest number of machinery-related injuries, accounting for 64.7 percent, at underground coal mines. This paper analyzes U.S. roof bolter fatal and nonfatal lost-time injury data at underground work locations for all commodities from 2004 through 2013 and determines risk indices for six roof bolting tasks. For fatal and nonfatal incidences combined, the roof bolting tasks in order of the highest to lowest risk index were bolting, handling of materials, setting the temporary roof support (TRS), drilling, tramming, and traversing. For fatalities, the roof bolting tasks in order of the highest to lowest risk index were handling of materials, setting the TRS, bolting, drilling, traversing, and tramming. Age was found to be a significant factor. Severity of injury, indicated by days lost, was found to increase with increasing age as well as with increasing experience, largely due to the confounding of age and experience. The operation of the roof bolting machine used in underground mining should be a research priority given the high frequency and severity of incidents. The results also suggest that temporal factors may exist, so additional research is warranted to better understand these factors and potentially develop interventions. This research provides a data-driven foundation from which future research can be conducted for safety interventions to reduce the frequency and severity of incidences involving the roof bolter activities of bolting, handling of materials, and setting the TRS. |
Physiologic Effects from Using Tight- and Loose-Fitting Powered Air-Purifying Respirators on Inhaled Gases, Peak Pressures, and Inhalation Temperatures During Rest and Exercise
Sinkule EJ , Powell JB , Rubinstein EN , McWilliams L , Quinn T , Pugliese M . J Int Soc Respir Prot 2016 33 (2) 36-52 The goal of this investigation was to evaluate the physiologic stresses of powered air-purifying respirators (PAPRs) used by workers in many industries (e.g., health care, automobile repair, public safety, building trades, etc.) during rest and three levels of energy expenditure. Twelve men and twelve women wore one tight-fitting and three loose-fitting PAPRs at rest (REST) and while walking for four minutes at oxygen consumption (V̇O(2)) rates of 1.0 l·min(-1)(LOW), 2.0 l·min(-1) (MODERATE), and 3.0 l·min(-1) or maximum (HIGH). Minimum inhaled carbon dioxide concentration (F(I)CO(2)), maximum inhaled oxygen concentration (F(I)O(2)), peak inhalation pressure, and end inhalation temperature were measured continuously breath-by-breath. Repeated measures analysis of variance found that neither the main effect of gender, nor any interactions involving gender were significant. The highest minimum F(I)CO(2) among PAPRs occurred for MODERATE and HIGH energy expenditures while wearing the loose-fitting PAPR with the largest dead space. The lowest maximum F(I)O(2) was observed during HIGH intensity energy expenditure also for the loose-fitting PAPR with the largest dead space. Among all PAPR models, peak inhalation pressures were negative at V̇O(2) > LOW, suggesting that peak inhalation flow was greater than blower flow. Results using the variables reported here suggest that PAPRs used at various levels of energy expenditure may be tolerated among healthy workers. Further research is needed to determine the source of supplemented air when inhalation flow exceeds blower flow. |
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