Analysis of the Silica Percent in Airborne Respirable Mine Dust Samples From U.S. Operations PDF Download
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Author: Steven Mischler
Publisher:
ISBN:
Category : Dust
Languages : en
Pages : 16
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Book Description
Exposure to crystalline silica in mining can lead to silicosis, a potentially fatal lung disease, and it may be contributing to the increase of coal workers' pneumoconiosis (CWP) seen in Appalachian miners. Exposure to silica in mines is controlled indirectly by reducing the respirable dust exposure limit through a formula that employs the % of silica in the dust. To reduce this exposure, control technologies and specific monitoring techniques need to be developed and implemented and the knowledge of the % of silica in mine dusts can help this process. This manuscript analyzes the % of silica in dust samples for the U.S. mining industry collected from 1997 to 2011. In the metal/nonmetal (M/NM) industry, metal and sand and gravel mines showed the highest silica % (8.2 %, 9.8 %) along with the highest variability. The silica % was found to be lower for samples collected in underground by comparison to surface and mill. In the coal industry, the samples collected in surface locations showed high silica % in the dust. For both the coal and M/NM industries, the % of silica and the respirable dust concentration were inversely related--i.e., the lower the dust concentration, the higher and more variable silica percentages were observed. The respirable dust limit formula suggests the first explanation: a mine with a high silica % in the dust is required to keep the dust concentration low under the reduced standard. Additional explanations are also proposed: the variability of the % of silica in the dust, the selective efficiency of control technologies, and different transport properties for dust with variable silica content. The findings improve the understanding of exposure to silica in mining environments and the data presented will be helpful in developing monitoring strategies for the measurement of silica and for the design of control technologies.
Author: Steven Mischler
Publisher:
ISBN:
Category : Dust
Languages : en
Pages : 16
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Book Description
Exposure to crystalline silica in mining can lead to silicosis, a potentially fatal lung disease, and it may be contributing to the increase of coal workers' pneumoconiosis (CWP) seen in Appalachian miners. Exposure to silica in mines is controlled indirectly by reducing the respirable dust exposure limit through a formula that employs the % of silica in the dust. To reduce this exposure, control technologies and specific monitoring techniques need to be developed and implemented and the knowledge of the % of silica in mine dusts can help this process. This manuscript analyzes the % of silica in dust samples for the U.S. mining industry collected from 1997 to 2011. In the metal/nonmetal (M/NM) industry, metal and sand and gravel mines showed the highest silica % (8.2 %, 9.8 %) along with the highest variability. The silica % was found to be lower for samples collected in underground by comparison to surface and mill. In the coal industry, the samples collected in surface locations showed high silica % in the dust. For both the coal and M/NM industries, the % of silica and the respirable dust concentration were inversely related--i.e., the lower the dust concentration, the higher and more variable silica percentages were observed. The respirable dust limit formula suggests the first explanation: a mine with a high silica % in the dust is required to keep the dust concentration low under the reduced standard. Additional explanations are also proposed: the variability of the % of silica in the dust, the selective efficiency of control technologies, and different transport properties for dust with variable silica content. The findings improve the understanding of exposure to silica in mining environments and the data presented will be helpful in developing monitoring strategies for the measurement of silica and for the design of control technologies.
Author: Robert W. Freedman
Publisher:
ISBN:
Category : Mine dusts
Languages : en
Pages : 16
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Book Description
Author: William C. Larson
Publisher:
ISBN:
Category : Dosimeters
Languages : en
Pages : 16
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Book Description
Author: Samuel A. Goldberg
Publisher:
ISBN:
Category : Coal mines and mining
Languages : en
Pages : 20
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Book Description
Author: United States. Mining Enforcement and Safety Administration
Publisher:
ISBN:
Category : Breathing apparatus
Languages : en
Pages : 66
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Book Description
Author: Ali Lashgari
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
The mining industry continues to be an important contributor to the American economy. However, there are a variety of health concerns associated with mining. Exposure to respirable silica dust is one of the sources of health risks in surface mines. A variety of respiratory diseases and other ailments, including silicosis and other non-malignant respiratory diseases, may be caused by exposure to respirable silica dust. The Mine Act of 1977 requires the Mine Safety and Health Administration (MSHA) to inspect mines every year. While one goal of these inspections is to ensure compliance with occupational health and safety regulations, Congresss overall intent was to improve the safety and health of Americas mine workers. MSHA conducts a vigorous respirable dust sampling program to ensure compliance with its regulations as part of its deterrence and compliance mandate. MSHA inspections are resource intensive and consume a significant percentage of the agencys annual appropriation. The question of whether MSHAs compliance-sampling program is accomplishing the intended outcome is one of continued interest to the Government Accountability Office, taxpayers, organized labor, industry, and mine workers. The goal of this research is to determine the efficacy of the MSHA compliance-sampling program for respirable silica dust in surface metal and nonmetal mining operations. It is difficult to evaluate the efficacy of the program in reducing silicosis among mine workers because of the incomplete knowledge of health outcomes among miners and many confounding variables. The consequences of excess silica exposure can take years to develop. It is often impossible to accurately determine where and when exposures occurred, and whether exposures are fully attributable to occupational sources. Therefore, other surrogate metrics are required to assess the extent to which MSHAs sampling program and enforcement activity is contributing to the intended outcome. Two surrogate measures, including deterrence effect and exposure reduction, can be used to inform this assessment.The objectives of this research include: (i) to determine the deterrence effect associated with the sampling program, (ii) to determine the extent to which mine worker exposure has changed, and (iii) to examine the MSHA compliance-sampling database for opportunities for improving the health of mine workers through the use of this database. These objectives will be achieved through analysis of the compliance-sampling database for the following specific aims: (i) to quantify the change in compliance over the period of the program, (ii) to determine the relationship, if any, between the number of samples taken in any inspection year (annual sampling load) and noncompliance frequency, (iii) to quantify the change in worker exposure over the period of the program, (iv) to explore evidence that the current sampling strategy could be changed to better identify overexposed occupations, and (v) to find evidence of gaps in knowledge, practices, or technologies that could reduce overexposure.The MSHA Compliance-sampling database for surface metal and nonmetal mining operations during the 19-year period from 1997 to 2015 was used in this study. Characteristics and limitations of the MSHA compliance-sampling database were considered in selecting the methods to analyze the database. Descriptive statistics of the database were used to determine if deterrence and exposure reduction effects exist. This method was also employed to determine relationships between annual sampling load and noncompliance frequency. As a part of the fourth specific aim, the database was examined for signs of unusual overexposures. Commodities and occupations with the highest and lowest noncompliance record were identified through Classification and Regression Tree analysis. A field study was planned to assess the potential value of the database to improve the health of mine workers by testing to determine whether the knowledge gained from the MSHA database analysis could be useful to identify gap areas knowledge, practices, or control technologies that could reduce overexposure. Personal and area samples were collected from several dimension stone cutting shops during the field trip, using Helmet-CAM tool, gravimetric samplers, and passive dust monitors. This research has determined that the MSHA compliance-sampling program fails to meet in many cases its intended purpose of improving health of mineworkers by insuring compliance and reducing exposure. In recent years, the noncompliance frequency percent (percentage of overall samples that are noncompliant) and average exposure level fluctuate from year to year with no strong downward trend. Therefore, deterrence and exposure reduction effects do not exist throughout the years. Deterrence and reduction in exposure exist only for some occupations and commodities, during short periods of time. Many other occupations showed a fairly constant level of noncompliance and exposure over the past years. There are also a few occupations and commodities that exhibited upward trends for noncompliance and exposure levels. For many occupations, the annual sampling load did not correlate to the annual noncompliance frequency. There are low-risk occupations (occupations that demonstrate relatively lower rate of overexposure) that are very frequently sampled by MSHA inspectors. The increase in the annual sampling load for low-risk occupations did not result in capturing more noncompliant samples. In addition, there are high-risk occupations that are less frequently inspected. The increase of sampling load in the case of high-risk occupations resulted in capturing more noncompliant samples. This indicates a lack of efficient sampling resource allocation, and also indicates that opportunities exist to improve MSHA sampling resource allocation based on knowledge generated using the database. The results of this study indicated that occupations such as stone cutter/polisher, bagging operator, and cleanup man are among high-risk occupations. On the other hand, there are occupations with very low probability of over-exposure that are very frequently sampled. Front-end loader operator, truck driver and backhoe operator are among those low-risk occupations. This study shows that data-driven methods could be useful tools to suggest improved sampling strategies that more effectively target high-risk occupations and commodities. This field study showed that the MSHA database could be used to determine occupations and commodities that are more often overexposed. Then, detailed exposure assessment methods can be used to determine areas and tasks that contribute to elevated exposure rates. Finally, the offending areas/tasks can be investigated to determine potential gaps including a gap in proper practice of existing control technologies, lack of effective control technology, or a gap in knowledge regarding sources of elevated exposure. It can also help in determining modifications that could be made to improve the health of mine workers through reducing their exposure level. The results of this study can help make certain inferences about the utility of the MSHA database for the purposes of: improving MSHAs sampling resource allocation; identifying gap areas (including gaps in knowledge, technology, or proper practice of existing interventions); and developing interventions that effectively target the true sources of exposure.
Author: SJ. Page
Publisher:
ISBN:
Category : Analysis
Languages : en
Pages : 14
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Book Description
Since 1982 standard calibration materials recommended for respirable crystalline silica analysis by the Mine Safety and Health Administration (MSHA) P7 Infrared Method and the National Institute for Occupational Safety and Health (NIOSH) X-ray Diffraction (XRD) Analytical Method 7500 have undergone minor changes in size distribution. However, a critical assumption has been made that the crystalline silica in ambient mine atmosphere respirable dust samples has also remained essentially unchanged in particle size distribution. The objective of this work, therefore, is to compare recent particle size distributions of underground coal mine dust and the silica component of these dusts with estimated aerodynamic particle size distributions of calibration standard materials MIN-U-SIL 5, Berkeley 5, and SRM 1878 used by two crystalline silica analysis techniques. This work provides resolution to a previously reported discrepancy involving the proper sample dilution for the particle sizing method used.
Author: Saboor Ahmad Torabi
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Coal was, is, and will be one of the major energy sources for our society. Coal mining activities, from extraction to utilization, intrinsically produce coal dust and its associated aerosols, which are known to be safety and health hazards. Within the mine dust aerosols, the exposure of the respirable crystalline silica (RCS) dust is the most toxic component for the coal workers. Excessive RCS exposure can potentially cause the development of disabling and irreversible lung disease which is known as silicosis. The silicosis cases and its related mortality trend are still high in the United States, and the recent resurgence of coal miners' lung disease sends an alarming sign for the industry. Characterization of the physiochemical properties of RCS is the prerequisite for the improved understanding of its toxicity and adverse effects on miners' respiratory system. In this study, the mineral composition of respirable coal mine dust (RCMD), and type (s) of crystalline silica with its varying degrees of crystallinity in the mine dust were investigated. For this purpose, samples were collected from the top of coal (ToC) and bottom of coal (BoC) rock strata, which are believed to have the highest amount of crystalline silica. In addition, we also collected rock samples from both the roof and pillar of a limestone mine in Pennsylvania to define its crystalline components for potential silica characterization. After preparing the lab-generated respirable dust using a cryomill, the X-ray diffraction (XRD) technique in combination with JADE software was employed to identify the mineral phases and determine the quantitative mineral composition. The results from the quantitative analysis revealed that quartz (crystalline silica), muscovite, kaolinite, and clinochlore are the most abundant minerals in the ToC and BoC strata. The average amount of crystalline silica (quartz) was assessed to be 25% in the ToC and 17.3% in the BoC samples from the Lower Freeport coal seam. The quartz content in the samples from the ToC strata of Lower Kittanning was found to be 16.5%. Furthermore, phase identification analyses determined that, among the quartz types, alpha quartz ([alpha]-quartz) is the only type that exists in the samples. The quantitative analysis also reported a considerable amount of amorphous content for all samples. The amorphous content associated with the samples from near the coal seam comparatively showed a higher quantity, suggesting that the coal-ToC and coal-BoC interfaces contain a significant amount of amorphous. The quantitative analyses of limestone samples reported high calcite and dolomite with negligible quartz content. The amount of quartz in the sample from the pillar of the limestone mine was 0.22%, whereas no quartz was reported for the sample from the roof of the same mine. According to the results, it is advisable to conduct additional elemental analysis to verify the mineral composition of the samples. Additionally, it is recommended to undertake comprehensive investigations into the mineralogy and toxicity of the amorphous content found in coal mine dust, especially those originating from the interfaces of coal and rock strata.
Author: Andrew B. Andrew B. Cecala
Publisher: CreateSpace
ISBN: 9781511722186
Category :
Languages : en
Pages : 312
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Book Description
Throughout the mining and processing of minerals, the mined ore undergoes a number of crushing, grinding, cleaning, drying, and product sizing operations as it is processed into a marketable commodity. These operations are highly mechanized, and both individually and collectively these processes can generate large amounts of dust. If control technologies are inadequate, hazardous levels of respirable dust may be liberated into the work environment, potentially exposing workers. Accordingly, federal regulations are in place to limit the respirable dust exposure of mine workers. Engineering controls are implemented in mining operations in an effort to reduce dust generation and limit worker exposure.
Author: Syd S. Peng
Publisher:
ISBN:
Category : Coal mines and mining
Languages : en
Pages : 278
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Book Description
