Anti-caking treated rock dust and its effect on downwind respirable dust measurements

2021 ◽  
pp. 317-325
Author(s):  
M.L. Harris ◽  
S. Klima ◽  
C.B. Brown ◽  
I.E. Perera ◽  
J.A. Addis ◽  
...  
Keyword(s):  
Respirable Dust ◽  
Rock Dust

scholarly journals Respirable dust measured downwind during rock dust application

2017 ◽  
Vol 69 (5) ◽  
pp. 69-74 ◽  
Author(s):  
M.L. Harris ◽  
J. Organiscak ◽  
S. Klima ◽  
I.E. Perera
Keyword(s):  
Respirable Dust ◽  
Rock Dust

Comparative assessment of morphological mechanisms of maintaining structural liver homeostasis in the dynamics of exposure to coal-rock dust and sodium fluoride on the body

2020 ◽  
pp. 189-194
Author(s):  
M. S. Bugaeva ◽  
O. I. Bondarev ◽  
N. N. Mikhailova ◽  
L. G. Gorokhova
Keyword(s):  
Sodium Fluoride ◽  
Morphological Changes ◽  
The Body ◽  
System Level ◽  
Production Factor ◽  
Coal Rock ◽  
The Impact ◽  
Structural Homeostasis ◽  
Rock Dust

Introduction. The impact on the body of such factors of the production environment as coal-rock dust and fluorine compounds leads to certain shift s in strict indicators of homeostasis at the system level. Maintaining the relative constancy of the internal environment of the body is provided by the functional consistency of all organs and systems, the leading of which is the liver. Organ repair plays a crucial role in restoring the structure of genetic material and maintaining normal cell viability. When this mechanism is damaged, the compensatory capabilities of the organ are disrupted, homeostasis is disrupted at the cellular and organizational levels, and the development of the main pathological processes is noted.The aim of the study is to compare the morphological mechanisms of maintaining structural homeostasis of the liver in the dynamics of the impact on the body of coal-rock dust and sodium fluoride.Materials and methods. Experimental studies were conducted on adult white male laboratory rats. Features of morphological mechanisms for maintaining structural homeostasis of the liver in the dynamics of exposure to coal-rock dust and sodium fluoride were studied on experimental models of pneumoconiosis and fluoride intoxication. For histological examination in experimental animals, liver sampling was performed after 1, 3, 6, 9, 12 weeks of the experiment.Results. The specificity of morphological changes in the liver depending on the harmful production factor was revealed. It is shown that chronic exposure to coal-rock dust and sodium fluoride is characterized by the development of similar morphological changes in the liver and its vessels from the predominance of the initial compensatory-adaptive to pronounced violations of the stromal and parenchymal components. Long-term inhalation of coal-rock dust at 1–3 weeks of seeding triggers adaptive mechanisms in the liver in the form of increased functional activity of cells, formation of double-core hepatocytes, activation of immunocompetent cells and endotheliocytes, ensuring the preservation of the parenchyma and the general morphostructure of the organ until the 12th week of the experiment. Exposure to sodium fluoride leads to early disruption of liver compensatory mechanisms and the development of dystrophic changes in the parenchyma with the formation of necrosis foci as early as the 6th week of the experiment.Conclusions. The study of mechanisms for compensating the liver structure in conditions of long-term exposure to coal-rock dust and sodium fluoride, as well as processes that indicate their failure, and the timing of their occurrence, is of theoretical and practical importance for developing recommendations for the timely prevention and correction of pathological conditions developing in employees of the aluminum and coal industry.The authors declare no conflict of interests.

scholarly journals Behavior of Quarry Rock Dust, Fly Ash and Slag Based Geopolymer Concrete Columns Reinforced with Steel Fibers under Eccentric Loading

2021 ◽  
Vol 11 (15) ◽  
pp. 6740
Author(s):  
Rana Muhammad Waqas ◽  
Faheem Butt
Keyword(s):  
Fly Ash ◽  
Concrete Cover ◽  
Steel Fibers ◽  
Structural Behavior ◽  
Partial Replacement ◽  
Geopolymer Concrete ◽  
Fiber Reinforced ◽  
Conventional Concrete ◽  
Source Materials ◽  
Rock Dust

Geopolymer concrete, also known as an earth-friendly concrete, has been under continuous study due to its environmental benefits and a sustainable alternative to conventional concrete construction. The supplies of many source materials, such as fly ash (FA) or slag (SG), to produce geopolymer concrete (GPC) may be limited; however, quarry rock dust (QRD) wastes (limestone, dolomite, or silica powders) formed by crushing rocks appear virtually endless. Although significant experimental research has been carried out on GPC, with a major focus on the mix design development, rheological, durability, and mechanical properties of the GPC mixes; still the information available on the structural behavior of GPC is rather limited. This has implications in extending GPC application from a laboratory-based technology to an at-site product. This study investigates the structural behavior of quarry-rock-dust-incorporated fiber-reinforced GPC columns under concentric and eccentric loading. In this study, a total of 20 columns with 200 mm square cross-section and 1000 mm height were tested. The FA and SG were used as source materials to produce GPC mixtures. The QRD was incorporated as a partial replacement (20%) of SG. The conventional concrete (CC) columns were prepared as the reference specimens. The effect of incorporating quarry rock dust as a replacement of SG, steel fibers, and loading conditions (concentric and eccentric loading) on the structural behavior of GPC columns were studied. The test results revealed that quarry rock dust is an adequate material that can be used as a source material in GPC to manufacture structural concrete members with satisfactory performance. The general performance of the GPC columns incorporating QRD (20%) is observed to be similar to that of GPC columns (without QRD) and CC columns. The addition of steel fibers considerably improves the loading capacity, ductility, and axial load–displacement behavior of the tested columns. The load capacities of fiber-reinforced GPC columns were about 5–7% greater in comparison to the CC columns. The spalling of concrete cover at failure was detected in all plain GPC columns, whereas the failure mode of all fiber-reinforced GPC columns is characterized with surface cracking leading to disintegration of concrete cover.

Office Environment Syndrome Study: Part II

1998 ◽  
Vol 42 (8) ◽  
pp. 639-642
Author(s):  
Alan Hedge ◽  
William A. Erickson
Keyword(s):  
Case Reports ◽  
Case Control ◽  
Self Report ◽  
Respirable Dust ◽  
Diary Study ◽  
Climate Conditions ◽  
Office Environment ◽  
Work Posture ◽  
Computer Mouse ◽  
Settled Dust

A longitudinal self-report diary study of SBS cases and controls identified from buildingwide surveys of 4 office buildings is described. Self-report diaries were distributed to a total of 214 workers in the 4 buildings, and complete returns were obtained for 123 workers (57% return rate). Climate conditions (CO, CO2, formaldehyde, respirable dust mass (PM3.5) and particulate counts (0.3 μm, 0.5 μm, 1 μm, 5 μm), settled dust, air temperature, %RH, illuminance) were measured at each workstation. Ergonomic factors (observed work posture, office type, desk paper coverage, desk clutter, computer, mouse, keyboard tray, age of chair, chair arms, and plants, were measured at each workstation. Results showed no differences in prevailing climate conditions measured at case/control workstations. However, case reports of symptoms and environment conditions generally were worse than those for controls, and these reports showed periodicity, peaking late each day. The differences between reports by cases and controls generally remained consistent throughout the duration of the study.

Coal mine dust lung disease in miners killed in the Upper Big Branch disaster: a review of lung pathology and contemporary respirable dust levels in underground US coal mines

2021 ◽  
pp. oemed-2021-107694
Author(s):  
Leonard H T Go ◽  
Francis H Y Green ◽  
Jerrold L Abraham ◽  
Andrew Churg ◽  
Edward L Petsonk ◽  
...  
Keyword(s):  
Lung Tissue ◽  
Geometric Mean ◽  
Coal Mines ◽  
Regulatory Compliance ◽  
Respirable Dust ◽  
Lung Pathology ◽  
Histopathological Findings ◽  
Exposure Limit ◽  
Underground Coal Mines ◽  
The Usa

ObjectivesIn 2010, 29 coal miners died due to an explosion at the Upper Big Branch (UBB) mine in West Virginia, USA. Autopsy examinations of 24 individuals with evaluable lung tissue identified 17 considered to have coal workers’ pneumoconiosis (CWP). The objectives of this study were to characterise histopathological findings of lung tissue from a sample of UBB fatalities and better understand the respirable dust concentrations experienced by these miners at UBB relative to other US coal mines.MethodsOccupational pulmonary pathologists evaluated lung tissue specimens from UBB fatalities for the presence of features of pneumoconiosis. Respirable dust and quartz samples submitted for regulatory compliance from all US underground coal mines prior to the disaster were analysed.ResultsFamilies of seven UBB fatalities provided consent for the study. Histopathologic evidence of CWP was found in all seven cases. For the USA, central Appalachia and UBB, compliance dust samples showed the geometric mean for respirable dust was 0.468, 0.420 and 0.518 mg/m3, respectively, and respirable quartz concentrations were 0.030, 0.038 and 0.061 mg/m3. After adjusting for quartz concentrations, UBB exceeded the US permissible exposure limit (PEL) for respirable dust in 28% of samples.ConclusionsAlthough higher than average respirable dust and quartz levels were observed at UBB, over 200 US underground coal mines had higher dust concentrations than UBB and over 100 exceeded the PEL more frequently. Together with lung histopathological findings among UBB fatalities, these data suggest exposures leading to CWP in the USA are more prevalent than previously understood.

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