Analysis of Free Silica in Respirable Dust PDF Download
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Author: Robert W. Freedman
Publisher:
ISBN:
Category : Mine dusts
Languages : en
Pages : 16
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Book Description
Author: Robert W. Freedman
Publisher:
ISBN:
Category : Mine dusts
Languages : en
Pages : 16
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Book Description
Author: Robert W. Freedman
Publisher:
ISBN:
Category : Mine dusts
Languages : en
Pages : 0
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Author: P. Menéndez Cabo
Publisher:
ISBN:
Category : Respirable crystalline silica
Languages : en
Pages : 22
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Book Description
There is an international debate about the possibility of lowering the current occupational exposure limits (OELs) for respirable crystalline silica (RCS). Part of the discussion centers on knowing whether the OEL adequately protects workers. Exposure sampling using low-flow-rate pumps forms the basis of epidemiological studies, and thus the Technical Department of the National Silicosis Institute has carried out a study into the precision of workplace measurements with personal respirable dust samplers. The study consisted of taking two samples (one from either side of the worker's breathing zone) during different types of activities (quarries, marble workshops, slate workshops) and in semi-controlled conditions (dust tunnel). A total of 366 sample pairs were obtained, of which 186 were acquired in the dust tunnel and 180 came from the workplace. The statistical analysis of the difference between the pairs of results, expressed as the percentage error, showed the following results for RCS in workplace measurements: the median was 27.4 % (range: 0 % to 181 %), the 75th percentile was 51.7 %, and the 25th percentile was 12.7 %. The workplace measurements were divided between two industry sectors (marble and slate workshops), which were examined separately. Results obtained in a dust tunnel showed that for RCS, the percentage error of the difference between the pairs of results had a median of 23.9 % (range: 0 % to 90 %) with a 75th percentile at 40.1 % and a 25th percentile at 11.1 %. The results from the dust tunnel were not found to be statistically significantly different from the field results. Several important conclusions were obtained: firstly, a single sample is not enough to adequately evaluate exposure in order to avoid errors stemming from differences in "valid" measurements as shown in the statistical analysis, and secondly, the main source of error is the variability of the dust concentration during real measurements.
Author: National Institute for Occupational Safety and Health
Publisher:
ISBN:
Category : Hazardous substances
Languages : en
Pages : 136
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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: 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:
Publisher:
ISBN:
Category : Industrial hygiene
Languages : en
Pages : 154
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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: 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:
Publisher:
ISBN:
Category : Industrial hygiene
Languages : en
Pages : 40
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Book Description
