Last data update: Jun 11, 2024. (Total: 46992 publications since 2009)
Records 1-4 (of 4 Records) |
Query Trace: Joy GJ [original query] |
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Laboratory results of a 3rd generation roof bolter canopy air curtain for respirable coal mine dust control
Reed WR , Joy GJ , Shahan M , Klima S , Ross G . Int J Coal Sci Technol 2019 6 (1) 15-26 Testing was completed on an earlier roof bolter CAC that used slots to provide a perimeter airflow. NIOSH tested it due to its unique design that differed from canopies that provided uniform airflow. Based upon NIOSH recommendations from the earlier testing, a 3rd generation roof bolter CAC has been developed by J.H. Fletcher & Co. The changes to this CAC involve design modifications to the plenum outlets, using a single row of outlets on the perimeter and a different material for the plenum. This laboratory testing was a continuation of the original perimeter slotted CAC design. Using gravimetric and instantaneous sampling of respirable dust concentrations underneath and outside of the CAC, the laboratory testing was completed using three different blower fans that delivered differing airflows. The maximum plenum airflow velocities ranged from 2.34 to 3.64 m/s (460–716 fpm). Results showed plenum respirable dust concentrations ranging from 34.6% to 49.3% lower than respirable dust concentrations outside the plenum protection zone, thus showing an improvement in protection for the roof bolter operators. |
Development of a roof bolter canopy air curtain for respirable dust control
Reed WR , Joy GJ , Kendall B , Bailey A , Zheng Y . Min Eng 2017 69 (1) 33-39 Testing of the roof bolter canopy air curtain (CAC) designed by the U.S. National Institute for Occupational Safety and Health (NIOSH) has gone through many iterations, demonstrating successful dust control performance under controlled laboratory conditions. J.H. Fletcher & Co., an original equipment manufacturer of mining equipment, further developed the concept by incorporating it into the design of its roof bolting machines. In the present work, laboratory testing was conducted, showing dust control efficiencies ranging from 17.2 to 24.5 percent. Subsequent computational fluid dynamics (CFD) analysis revealed limitations in the design, and a potential improvement was analyzed and recommended. As a result, a new CAC design is being developed, incorporating the results of the testing and CFD analysis. |
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. |
Evaluation of the approach to respirable quartz exposure control in U.S. coal mines
Joy GJ . J Occup Environ Hyg 2012 9 (2) 65-8 Occupational exposure to high levels of respirable quartz can result in respiratory and other diseases in humans. The Mine Safety and Health Adminstration (MSHA) regulates exposure to respirable quartz in coal mines indirectly through reductions in the respirable coal mine dust exposure limit based on the content of quartz in the airborne respirable dust. This reduction is implemented when the quartz content of airborne respirable dust exceeds 5% by weight. The intent of this dust standard reduction is to restrict miners' exposure to respirable quartz to a time-weighted average concentration of 100 mcg/m(3). The effectiveness of this indirect approach to control quartz exposure was evaluated by analyzing respirable dust samples collected by MSHA inspectors from 1995 through 2008. The performance of the current regulatory approach was found to be lacking due to the use of a variable property-quartz content in airborne dust-to establish a standard for subsequent exposures. In one situation, 11.7% (4370/37,346) of samples that were below the applicable respirable coal mine dust exposure limit exceeded 100 mcg/m(3) quartz. In a second situation, 4.4% (895/20,560) of samples with 5% or less quartz content in the airborne respirable dust exceeded 100 mcg/m(3) quartz. In these two situations, the samples exceeding 100 mcg/m(3) quartz were not subject to any potential compliance action. Therefore, the current respirable quartz exposure control approach does not reliably maintain miner exposure below 100 mcg/m(3) quartz. A separate and specific respirable quartz exposure standard may improve control of coal miners' occupational exposure to respirable quartz. |
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