Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-5 (of 5 Records) |
Query Trace: Potts JD[original query] |
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Design of different shapes of drill shroud to reduce dust deposit using computational fluid dynamics method
Zheng Y , Reed WR , Potts JD . CIM J 2023 11-20 Effective dust control using drill shroud air-blocking shelves was confirmed previously through laboratory tests, field studies, and computational fluid dynamics (CFD) simulations. However, when the drilling machine moves to different locations, deposits on these shelves can produce a large dust cloud. To minimize the dust exposure hazard, this study modified the drill shroud air-blocking shelves by using the concept of angle of repose to eliminate the deposits while at the same time, confining the dust inside the drill shroud. Two types of drill shroud inner shapes were evaluated using CFD models: U-shaped and V-shaped. In addition, a drill shroud with 45 blocking shelves was built to examine its dust control capacity. The angle of repose used to minimize dust problems during mast lowering was shown to be effective in reducing the dust problems during drilling. However, care must be taken to use a properly designed shroud because the V-shaped drill shroud can potentially exacerbate dust leakage. |
Work practices and respiratory health status of Appalachian coal miners with progressive massive fibrosis
Reynolds LE , Blackley DJ , Colinet JF , Potts JD , Storey E , Short C , Carson R , Clark KA , Laney AS , Halldin CN . J Occup Environ Med 2018 60 (11) e575-e581 OBJECTIVE: To characterize workplace practices and respiratory health among coal miners with large opacities consistent with progressive massive fibrosis (PMF) who received care at a federally-funded black lung clinic network in Virginia. METHODS: Participants were interviewed about their workplace practices and respiratory health. Medical records were reviewed. RESULTS: Nineteen former coal miners were included. Miners reported cutting rock, working downwind of dust-generating equipment, non-adherence to mine ventilation plans (including dust controls), improper sampling of respirable coal mine dust exposures, working after developing respiratory illness, and suffering from debilitating respiratory symptoms. CONCLUSIONS: Consistent themes of suboptimal workplace practices contributing to development of PMF emerged during the interviews. Some of the practices reported were unsafe and unacceptable. Further research is needed to determine the prevalence of these factors and how best to address them. |
Dust control by air-blocking shelves and dust collector-to-bailing airflow ratios for a surface mine drill shroud
Zheng Y , Reed WR , Potts JD , Li M , Rider JP . Min Eng 2018 70 (5) 69-74 The National Institute for Occupational Safety and Health (NIOSH) recently developed a series of validated models utilizing computational fluid dynamics (CFD) to study the effects of air-blocking shelves on airflows and respirable dust distribution associated with medium-sized surface blasthole drill shrouds as part of a dry dust collector system. Using validated CFD models, three different air-blocking shelves were included in the present study: a 15.2-cm (6-in.)-wide shelf; a 7.6-cm (3-in.)-wide shelf; and a 7.6-cm (3-in.)-wide shelf at four different shelf heights. In addition, the dust-collector-to-bailing airflow ratios of 1.75:1, 1.5:1, 1.25:1 and 1:1 were evaluated for the 15.2-cm (6-in.)-wide air-blocking shelf. This paper describes the methodology used to develop the CFD models. The effects of air-blocking shelves and dust collector-to-bailing airflow ratios were identified by the study, and problem regions were revealed under certain conditions. © 2018 Society for Mining, Metallurgy and Exploration. All rights reserved. |
Influence of continuous mining arrangements on respirable dust exposures
Beck TW , Organiscak JA , Pollock DE , Potts JD , Reed WR . Trans Soc Min Metall Explor Inc 2016 340 (1) 1-10 In underground continuous mining operations, ventilation, water sprays and machine-mounted flooded-bed scrubbers are the primary means of controlling respirable dust exposures at the working face. Changes in mining arrangements - such as face ventilation configuration, orientation of crosscuts mined in relation to the section ventilation and equipment operator positioning - can have impacts on the ability of dust controls to reduce occupational respirable dust exposures. This study reports and analyzes dust concentrations measured by the Pittsburgh Mining Research Division for remote-controlled continuous mining machine operators as well as haulage operators at 10 U.S. underground mines. The results of these respirable dust surveys show that continuous miner exposures varied little with depth of cut but are significantly higher with exhaust ventilation. Haulage operators experienced elevated concentrations with blowing face ventilation. Elevated dust concentrations were observed for both continuous miner operators and haulage operators when working in crosscuts driven into or counter to the section airflow. Individual cuts are highlighted to demonstrate instances of minimal and excessive dust exposures attributable to particular mining configurations. These findings form the basis for recommendations for lowering face worker respirable dust exposures. |
Field evaluation of air-blocking shelf for dust control on blasthole drills
Potts JD , Reed WR . Int J Min Reclam Environ 2011 25 (1) 32-40 In previous studies, an air-blocking shelf has been shown to be successful in reducing respirable dust leakage from the drill shroud in a laboratory setting. Dust reductions of up to 81% were achieved with the shelf under operating conditions consisting of a 1.9:1 collector-to-bailing airflow ratio and a 5.1-cm gap between the shroud and ground. Recent research focused on evaluating the shelf on two actual operating blasthole drills, in much more severe environments. In the field, the shelf reduced dust levels in the areas surrounding one operating blasthole drill by 70%. Dust reductions measured in the immediate vicinity of the shroud were reduced by 66% at one mine and 81% at the other mine. These field tests confirm that the air-blocking shelf is useful for reducing respirable dust generation from blasthole drills. |
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