Last data update: Jun 17, 2024. (Total: 47034 publications since 2009)
Records 1-10 (of 10 Records) |
Query Trace: Rider JP [original query] |
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Evaluation of roof bolter canopy air curtain effects on airflow and dust dispersion in an entry using blowing curtain ventilation
Zheng Y , Reed WR , Shahan MR , Rider JP . Min Metall Explor 2019 36 (6) [Epub ahead of print] Roof bolter operators may be exposed to high respirable dust concentrations on continuous miner sections with blowing face ventilation when bolting is performed downwind of the continuous miner. One solution to reduce the high respirable dust concentrations is to use a canopy air curtain (CAC) to deliver clean air from a filtered blower fan directly to the bolter operators under the canopies. The influence of CAC installation in the airflow and dust dispersion around the location of the roof bolter operator can be evaluated by using computational fluid dynamics (CFD). This study, performed by the National Institute for Occupational Safety and Health (NIOSH), considers two scenarios: (1) a roof bolting machine in the center of the entry for installation of the fifth row of bolts from the face, and (2) a roof bolting machine positioned close to the face for the installation of the last row of bolts. In both scenarios, the bolting machine is placed in an environment which contains 6.0 mg/m3 of respirable dust and is ventilated by a blowing curtain with 3000 cfm (1.42 m3/s) of air. This environment is used to simulate the roof bolter machine operating downstream of a continuous mining machine. Two operation positions are simulated at the same bolting location: dual drill heads in the inward position for two inside bolts and dual drill heads in the outward position for two outside bolts. The influence of the CAC on airflows and dust dispersion is evaluated with the CAC operating at 250 cfm (0.12 m3/s). |
Improving protection against respirable dust at an underground crusher booth
Patts JR , Cecala AB , Rider JP , Organiscak JA . Min Eng 2018 70 (11) 48-52 The U.S. National Institute for Occupational Safety and Health completed a 15-month study at an underground limestone mine crusher booth that evaluated three research parameters: (1) the effectiveness of a filtration and pressurization system for improving the air quality inside the operator booth, (2) the relative effectiveness of n > 99 and n > 95 experimental prototype filters in the system, and (3) the performance of three different cab pressure monitoring devices. The protection factor was quantified monthly using particle counters in the respirable dust range of 0.3 to 1 urn particle size, and gravimetric dust samples were gathered at the beginning and end of the overall study. Under static (closed-door) conditions, the filtration unit offered a gravimetric calculated protection factor between 10 and 31, depending on the filter type and loading condition. The monthly particle counting analysis shows that the n > 95 filter offers a protection factor nearly five times that of the n > 99 filter, where n = 15 samples. The booth pressure monitors were tested and proved to be a valid indicator of system performance over time. © Society for Mining Metallurgy and Exploration. All rights reserved. |
Design and experimental evaluation of a flooded-bed dust scrubber integrated into a longwall shearer
Arya S , Sottile J , Rider JP , Colinet JF , Novak T , Wedding C . Powder Technol 2018 339 487-496 Continuous mining machines operating in U.S. underground coal mines have, for decades, utilized flooded-bed dust scrubbers for capturing and removing respirable dust generated at the production face. However, the application of dust scrubbers to longwall mining systems has not yet been successful. Considering that nearly 60% of U.S. underground coal production is from longwall mines, the successful application of dust scrubbers to longwall mining systems could have a significant impact on miner health. A full-scale mock-up of a longwall shearer was constructed and equipped with a flooded-bed dust scrubber designed to capture dust produced by the headgate cutting drum. The mockup was installed at the National Institute for Occupational Safety and Health (NIOSH) Longwall Dust Gallery and a series of 40 experiments was conducted to evaluate the scrubber's performance. Results show that the scrubber achieved a 56% reduction of respirable dust in the return airway and a 74% reduction of respirable dust in the walkway area near the shearer. Although these tests were conducted under a controlled environment, the results suggest that a similar scrubber design could be very effective at achieving a significant reduction in respirable dust in longwall mining systems. |
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. |
CFD gas distribution analysis for different continuous-miner scrubber redirection configurations
Zheng Y , Organiscak JA , Zhou L , Beck TW , Rider JP . Trans Soc Min Metall Explor Inc 2017 342 (1) 15-21 The U.S. National Institute for Occupational Safety and Health (NIOSH)'s Pittsburgh Mining Research Division (PMRD) recently developed a series of models using computational fluid dynamics (CFD) to study gas distribution around a continuous mining machine with various fan-powered flooded bed scrubber discharge configurations in an exhaust curtain working face. CFD models utilizing species transport model without reactions in FLUENT were constructed to evaluate the redirection of scrubber discharge toward the mining face rather than behind the return curtain. The study illustrates the gas distribution in the slab (second) cut. The following scenarios are considered in this study: 100 percent of the discharge redirected back toward the face on the off-curtain side; 100 percent of the discharge redirected back toward the face, but divided equally to both sides; and 15 percent of the discharge redirected toward the face on the off-curtain side, with 85 percent directed toward the return curtain. These models are compared against a model with a conventional scrubber discharge where air is directed away from the face into the return. The models were validated against experimental data, proving to accurately predict sulfur hexafluoride (SF6) gas levels at four gas monitoring locations. This study includes a predictive simulation examining a 45 degrees scrubber angle compared with the 23 degrees angle for the 100 percent redirected, equally divided case. This paper describes the validation of the CFD models based on experimental data of the gas distribution results. |
Computational fluid dynamic modeling of a medium-sized surface mine blasthole drill shroud
Zheng Y , Reed WR , Zhou L , Rider JP . Min Eng 2016 68 (11) 43-49 The Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health (NIOSH) recently developed a series of models using computational fluid dynamics (CFD) to study airflows and respirable dust distribution associated with a mediumsized surface blasthole drill shroud with a dry dust collector system. Previously run experiments conducted in NIOSH's full-scale drill shroud laboratory were used to validate the models. The setup values in the CFD models were calculated from experimental data obtained from the drill shroud laboratory and measurements of test material particle size. Subsequent simulation results were compared with the experimental data for several test scenarios, including 0.14 m3/s (300 cfm) and 0.24 m3/s (500 cfm) bailing airflow with 2:1, 3:1 and 4:1 dust collector-tobailing airflow ratios. For the 2:1 and 3:1 ratios, the calculated dust concentrations from the CFD models were within the 95 percent confidence intervals of the experimental data. This paper describes the methodology used to develop the CFD models, to calculate the model input and to validate the models based on the experimental data. Problem regions were identified and revealed by the study. The simulation results could be used for future development of dust control methods for a surface mine blasthole drill shroud. |
CFD analysis on gas distribution for different scrubber redirection configurations in sump cut
Zheng Y , Organiscak JA , Zhou L , Beck TW , Rider JP . Trans Soc Min Metall Explor Inc 2015 338 (1) 423-432 The National Institute for Occupational Safety and Health's Office of Mine Safety and Health Research recently developed a series of models using computational fluid dynamics (CFD) to study the gas distribution around a continuous mining machine with various fan-powered flooded bed scrubber discharge configurations. CFD models using Species Transport Model without reactions in FLUENT were constructed to evaluate the redirection of scrubber discharge toward the mining face rather than behind the return curtain. The following scenarios are considered in this study: 100 percent of the discharge redirected back toward the face on the off-curtain side of the continuous miner; 100 percent of the discharge redirected back toward the face, but divided equally to both sides of the machine; and 15 percent of the discharge redirected toward the face on the off-curtain side of the machine, with 85 percent directed into the return. These models were compared against a model with a conventional scrubber discharge, where air is directed away from the face into the return. The CFD models were calibrated and validated based on experimental data and accurately predicted sulfur hexafluoride (SF(6)) gas levels at four gas monitoring locations. One additional prediction model was simulated to consider a different scrubber discharge angle for the 100 percent redirected, equally divided case. These models identified relatively high gassy areas around the continuous miner, which may not warrant their use in coal mines with medium to high methane liberation rates. This paper describes the methodology used to develop the CFD models, and the validation of the models based on experimental data. |
Debilitating lung disease among surface coal miners with no underground mining tenure
Halldin CN , Reed WR , Joy GJ , Colinet JF , Rider JP , Petsonk EL , Abraham JL , Wolfe AL , Storey E , Laney AS . J Occup Environ Med 2015 57 (1) 62-7 OBJECTIVE: To characterize exposure histories and respiratory disease among surface coal miners identified with progressive massive fibrosis from a 2010 to 2011 pneumoconiosis survey. METHODS: Job history, tenure, and radiograph interpretations were verified. Previous radiographs were reviewed when available. Telephone follow-up sought additional work and medical history information. RESULTS: Among eight miners who worked as drill operators or blasters for most of their tenure (median, 35.5 years), two reported poor dust control practices, working in visible dust clouds as recently as 2012. Chest radiographs progressed to progressive massive fibrosis in as few as 11 years. One miner's lung biopsy demonstrated fibrosis and interstitial accumulation of macrophages containing abundant silica, aluminum silicate, and titanium dust particles. CONCLUSIONS: Overexposure to respirable silica resulted in progressive massive fibrosis among current surface coal miners with no underground mining tenure. Inadequate dust control during drilling/blasting is likely an important etiologic factor. |
Benchmarking longwall dust control technology and practices
Rider JP , Colinet JF . Min Eng 2011 63 (9) 74-80 Significant advances in longwall mining technology and equipment have occurred over the last decade. By the late 1990s, longwall mine output accounted for 40% of all underground output in the U.S. and today longwall mines account for approximately 50% of coal produced underground in the United States. A 51% increase in average shift production rates has occurred over the last 15 years. This increased longwall productivity has meant that far more dust is being produced and controlling respirable coal dust presents an ongoing challenge for coal mine operators. The National Institute for Occupational Safety and Health (NIOSH) conducted a series of benchmark surveys at longwall operations across the country to identify current operating practices and the types of controls being used. Gravimetric and instantaneous dust sampling was completed to quantify the dust levels generated by major sources on the longwall section and to identify different control technologies in use today. Substantial reductions in dust levels were realized at sampling locations on the face when compared with longwall surveys conducted in the 1990s. Results from the underground dust surveys and current longwall dust control technology and operating practices will be discussed. |
Controlling dust exposures in longwall mining utilizing a simple barrier
Sweeney DD , Slagley JM , Smith DA , Rider JP . Min Eng 2009 61 (12) 58-61 The United States coal mining industry has traditionally experienced difficulty in controlling dust levels below the occupational exposure limit. While improvements in face ventilation and water spray nozzles have decreased dust exposures, approximately eight percent of experienced coal miners are still developing Coal Worker's Pneumoconiosis. This investigation tested the feasibility of enhancing existing engineering dust controls by mounting a simple barrier on a longwall shearer that separated the operators from the cutting drums. The barrier was constructed and tested above ground at the National Institute for Occupational Safety and Health Pittsburgh Research Laboratory longwall gallery test facility. A 96-percent reduction of respirable dust occurred at the headgate sampling position when tested at 2.4 m/sec (480 ft/min). The average dust level decreased from 39 mg/m3 to 1.5 mg/m3 by utilizing the barrier. |
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