Respiratory Protection Provided by Negative Pressure Half Mask Filtering Respirators in Coal Mines

2018 ◽  
Vol 277 ◽  
pp. 232-240 ◽  
Author(s):  
Sergiy Cheberiachko ◽  
Olena Yavors’ka ◽  
Dmytro Radchuk ◽  
Andrii Yavorskyi
Keyword(s):  
Negative Pressure ◽  
Occupational Diseases ◽  
Coal Mines ◽  
Dust Concentration ◽  
Respiratory Protection ◽  
Breathing Zone ◽  
Sampling System ◽  
Total Dust ◽  
Exposure Limit ◽  
Low Efficiency

Two studies were conducted in the coal mines to evaluate worker exposures to a dust, and the effectiveness of air-purifying negative-pressure half mask respirators and was found that miners’ protection were insufficient. An elastomeric and filtering half-mask negative pressure respirators with (mid-efficiency) filters P2 (FFP2) were studied. Measurements of total dust concentrations in the in-mask and outer air were conducted simultaneously. Not identical sampling system led to an underestimation of the actual total inside dust concentration in the first study. The results have been corrected to reduce the systematic error. The inside total dust concentrations Ci exceeded national Permissible Exposure Limit (PEL) in most cases in both studies; in first GM Ci=24.7 mg/m3; in second 8.6 mg/m3. Protection factors were: from 2.9 to 6.9 in first study; and from 5.6 to 34 in second. Low efficiency of respirators can be caused by its non-continuous usage. High risk of miners’ occupational diseases should be reduced by decreasing the dust concentration in the breathing zone. It is advisable to check the possibility of improving respiratory protection of miners by powered air-purifying respirators.

scholarly journals The effectiveness of the miners’ respirators

2021 ◽  
Vol 100 (2) ◽  
pp. 129-134
Author(s):  
Sergej I. Cheberyachko ◽  
Dmitrij I. Radchuk ◽  
Oleg V. Deryugin
Keyword(s):  
Negative Pressure ◽  
High Efficiency ◽  
Coal Mines ◽  
Dust Concentration ◽  
Protection Factor ◽  
Exposure Limit ◽  
Respiratory Protective Devices ◽  
Continuous Use ◽  
The Impact ◽  
Dust Load

Introduction. Dust is one of the main harmful factors in underground coal mining. The dust concentration in the coal mines remains high due to the imperfection of the used technologies, increasing the pneumoconiosis risk in miners. Respirators are the last means of protection, but information about their effectiveness is contradictory. Aim. Assess the effectiveness of individual respiratory protective devices in the coal mines. Material and methods. The protection factor (PF), the ratio of the dust concentration outside the mask to the concentration under the mask) is used to assess respirators’ effectiveness. We measured the PFs in the laboratory and the workplaces. We also measured the time the miners did not use respirators. The measurements’ results were used as input data for mathematical modeling to reduce dust load reduction. Results. The concentration of dust under the mask exceeded the Occupational Exposure Limit (OEL) in most cases. Information about the high efficiency of the negative pressure half-mask respirators (in case of continuous use) was not confirmed. The PFs measured under laboratory conditions reached 6.2, and in the workplace were from 5 to 31. The miners did not use respirators from 10 to 45% of the shift duration (15 measurements). The measurements and information on the concentration of dust in 5 mines were used to simulate the impact of the respirators’ usage on the dust load. Calculations performed by different methods, and using various programs, gave the same result. The negative pressure half-mask respirators cannot reduce the dust’s concentration in the inhaled air to the OEL even with continuous use. Conclusion. The results showed that the respirators’ usage could not prevent developing incurable pneumoconiosis in miners.

Working conditions and occupational pathology of coal miners in the Arctic

2019 ◽  
pp. 452-457 ◽  
Author(s):  
S. A. Gorbanev ◽  
S. A. Syurin ◽  
N. M. Frolova
Keyword(s):  
Coal Mining ◽  
Working Conditions ◽  
Occupational Diseases ◽  
Climatic Factors ◽  
Coal Mines ◽  
The Arctic ◽  
Morbidity Rate ◽  
Coal Miners ◽  
Increased Risk ◽  
The Impact

Introduction. Due to the impact of adverse working conditions and climate, workers in coal-mining enterprises in the Arctic are at increased risk of occupational diseases (OD).The aim of the study was to study the working conditions, causes, structure and prevalence of occupational diseases in miners of coal mines in the Arctic.Materials and methods. Th e data of social and hygienic monitoring “Working conditions and occupational morbidity” of the population of Vorkuta and Chukotka Autonomous District in 2007–2017 are studied.Results. It was established that in 2007–2017 years, 2,296 ODs were diagnosed for the first time in 1851 coal mines, mainly in the drifters, clearing face miners, repairmen and machinists of mining excavating machines. Most often, the ODs occurred when exposed to the severity of labor, fibrogenic aerosols and hand-arm vibration. The development of professional pathology in 98% of cases was due to design flaws of machines and mechanisms, as well as imperfections of workplaces and technological processes. Diseases of the musculoskeletal system (36.2%), respiratory organs (28.9%) and nervous system (22.5%) prevailed in the structure of professional pathology of miners of coal mines. Among the three most common nosological forms of OD were radiculopathy (32.1%), chronic bronchitis (27.7%) and mono-polyneuropathy (15.4%). In 2017, coal miners in the Arctic had a professional morbidity rate of 2.82 times higher than the national rates for coal mining.Conclusions. To preserve the health of miners of coal mining enterprises, technical measures to improve working conditions and medical interventions aimed at increasing the body’s resistance to the effects of harmful production and climatic factors are necessary.

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.

scholarly journals Dust Concentration Changing Regularities and Dust Reduction Technology by Spray Negative Pressure in Fully Mechanized Mining Face

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Lirong Wu ◽  
Hongxuan Chen ◽  
Jiamin Li ◽  
Shican Fu ◽  
Yuyan Zhuang
Keyword(s):  
Negative Pressure ◽  
Flow Characteristics ◽  
Dust Concentration ◽  
Inlet Section ◽  
Coal Face ◽  
Dust Suppression ◽  
Mining Face ◽  
Dust Distribution ◽  
Dust Reduction ◽  
Ventilation Velocity

The dust concentration changing regularities are the basis to take dust depression measures, which is greatly influenced by the airflow. In the software of FLUENT, the value of ventilation velocity is set as a constant, which cannot express the real ventilation. According to the flow characteristics of the sublayer and data from Nicholas’ experiment, the ventilation velocity distribution formula of sublayer in the inlet section of fully mechanized caving coal face is deduced. The boundary condition of velocity is given by UDF. Taking the 3top1110 fully mechanized caving coal face as an example, the dust distribution in the process of coal mining and hydraulic support shifting was studied. According to the dust-spray coupling experiment, three types of nozzle are chosen based on the efficiency of dust suppression. Combining the dust migration rule and the characteristics of nozzles, the negative pressure-secondary dust suppression devices of spray were developed and applied. And the above measures have lowered the dust concentration effectively.

scholarly journals Benzene Exposure and Biomarkers in Alveolar Air and Urine Among Deck Crews on Tankers Transporting Gasoline

2019 ◽  
Vol 63 (8) ◽  
pp. 890-897 ◽  
Author(s):  
Karl Forsell ◽  
Ingrid Liljelind ◽  
Göran Ljungkvist ◽  
Rolf Nordlinder ◽  
Eva Andersson ◽  
...  
Keyword(s):  
Weighted Average ◽  
Occupational Exposures ◽  
Exposure Level ◽  
Respiratory Protection ◽  
Muconic Acid ◽  
Alveolar Air ◽  
Benzene Exposure ◽  
Exposure Limit ◽  
Level Of Significance ◽  
Post Shift

Abstract Introduction Increased rates of leukaemia have been found among tanker crews. Occupational exposures to the leukomogen benzene during loading, unloading, and tank cleaning are possible causes. Studies on older types of tankers carrying gasoline with most handling being done manually have revealed important exposures to benzene. Our study explores benzene exposures on tankers with both automatic and manual systems. Correlations between benzene exposure and benzene in alveolar air (AlvBe), benzene in urine (UBe), and trans,trans-muconic acid (ttMA) in urine were investigated. Methods Forty-three male seafarers (22 deck crewmembers and 21 not on deck) on five Swedish different product and chemical tankers transporting 95- or 98-octane gasoline were investigated between 1995 and 1998. The tankers used closed systems for the loading and unloading of gasoline but stripping and tank cleaning were done manually. Benzene in respiratory air was measured using personal passive dosimeters during a 4-h work shift. Samples for biomarker analyses were collected pre- and post-shift. Smoking did occur and crewmembers did not use any respiratory protection during work. Results The average 4-h benzene exposure level for exposed was 0.45 mg m−3 and for non-exposed 0.02 mg m−3. Benzene exposure varied with type of work (range 0.02–143 mg m−3). AlvBe, UBe, and ttMA were significantly higher in post-shift samples among exposed and correlated with exposure level (r = 0.89, 0.74, and 0.57, respectively). Smoking did not change the level of significance among exposed. Discussion Benzene in alveolar air, unmetabolized benzene, and ttMA in urine are potential biomarkers for occupational benzene exposure. Biomarkers were detectable in non-exposed, suggesting benzene exposure even for other work categories on board tankers. Work on tankers carrying gasoline with more or less closed handling of the cargo may still lead to significant benzene exposure for deck crewmembers, and even exceed the Swedish Occupational Exposure Limit (OEL; 8-h time-weighted average [TWA]) of 1.5 mg m−3.

scholarly journals Adoption of Exposure Assessment Tools to Assist in Providing Respiratory Protection Recommendations

2020 ◽  
Vol 64 (5) ◽  
pp. 547-557
Author(s):  
Eun Gyung Lee ◽  
Diana M Ceballos
Keyword(s):  
Exposure Assessment ◽  
Industrial Hygiene ◽  
Assessment Tools ◽  
Final Decision ◽  
Respiratory Protection ◽  
Health Administration ◽  
Data Set ◽  
Exposure Data ◽  
Exposure Limit ◽  
Data Point

Abstract Selecting a proper respirator requires determining the ratio of an employee’s maximum use concentration (MUC) divided by the occupational exposure limit of a chemical. Current industrial hygiene practice often is to obtain a percentile estimate (e.g. 95th) of the measured exposure distribution to apply as the MUC. However, practitioners who are not yet familiar with statistical or mathematical approaches may choose the highest exposure data point as the MUC, a method that is still considered appropriate by the Occupational Safety and Health Administration. Nonetheless, choosing a respirator using the highest exposure data point when only limited data are available may result in not always providing the most adequate respirator. Because some practitioners are not familiar with exposure assessment tools, our primary goal in this study was to demonstrate the best process when selecting respiratory protection by using a combination of exposure data and assessment tools. Three user-friendly tools, IHDataAnalyst, Advanced REACH Tool, and IHSTAT, were selected to demonstrate how to use different types of tool outputs when choosing a respirator. A decision logic was developed to help users navigate the combining of different data inputs. Personal full-shift exposure data collected in four different workplaces were used to describe four different outcomes generated when the maximum exposure data point and the tool’s output are compared with the exposure limit of the chemical. Outcomes varied, from determinations of ‘high confidence’ (or final decision) to ‘low confidence’ (or indicating more data are needed) in the selection of a respirator recommendation. In conclusion, systematically adopting the combination of exposure data and assessment tools could increase practitioners’ confidence in decision-making when choosing respirators from a limited exposure data set. These suggested guidelines will lead practitioners toward good industrial hygiene practices.

scholarly journals Experimental Research and Numerical Simulation of Ejector Precipitator in a Fully Mechanized Mining Face

2020 ◽  
Vol 45 (11) ◽  
pp. 9815-9833
Author(s):  
Guodong Zhai ◽  
Wentao Zhang ◽  
Yaozong Li ◽  
Xinghao Lu ◽  
Wenyuan Hu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Negative Pressure ◽  
Coal Dust ◽  
Structural Parameters ◽  
Dust Concentration ◽  
Dust Removal ◽  
Measuring Point ◽  
Mining Face ◽  
Supply Water

AbstractIn order to effectively reduce the coal dust concentration in a fully mechanized mining face, this research used laboratory experiment, numerical simulation, and field test to conduct an in-depth exploration of the ejector precipitator installed at the low-level caving coal hydraulic support. Firstly, through the experimental platform in the laboratory, the dust removal effect of the nozzle with different structural parameters was tested, and the 3D particle dynamic analyzer was adopted to verify its atomization characteristics; then, the structural parameters corresponding to the nozzle in the best test results were obtained. Secondly, by using Fluent, the negative pressure flow field in the ejector barrel was numerically simulated. The results indicated that when the pressure of supply water was 12 MPa, the negative pressure value formed in the flow field was the lowest and the inspiratory velocity was the largest, which was conducive to dust removal. Finally, the tests of liquid–gas ratio and dust removal ratio were carried out in a fully mechanized mining face. The results showed that when the nozzle specification recommended by the experiment and the pressure of supply water recommended by the numerical simulation were used, the removal ratios of the total coal dust and the respirable coal dust were 89.5% and 91.0%, respectively, at the measuring point of the highest coal dust concentration. It indicates that the ejector precipitator has a good application effect in reducing the coal dust concentration in a fully mechanized mining face and improving the work environment of coal mine workers.

scholarly journals Surgical Team Exposure to Cautery Smoke and Its Mitigation during Tonsillectomy

2020 ◽  
Vol 163 (3) ◽  
pp. 508-516
Author(s):  
Daniel C. O’Brien ◽  
Eun Gyung Lee ◽  
Jhy-Charm Soo ◽  
Sherri Friend ◽  
Sarah Callaham ◽  
...  
Keyword(s):  
Methylene Chloride ◽  
Case Series ◽  
Chemical Compounds ◽  
Chemical Exposure ◽  
Breathing Zone ◽  
Surgical Smoke ◽  
Adverse Health Effects ◽  
Exposure Limit ◽  
Exposure Levels ◽  
Prospective Case Series

Objectives To assess the exposure of surgical personnel to known carcinogens during pediatric tonsillectomy and adenoidectomy (T&A) and compare the efficacy of surgical smoke evacuation systems during T&A. Study Design Prospective, case series. Setting Tertiary children’s hospital. Subjects and Methods The present study assessed operating room workers’ exposure to chemical compounds and aerosolized particulates generated during T&A. We also investigated the effect of 3 different smoke-controlling methods: smoke-evacuator pencil cautery (SE), cautery with suction held by an assistant (SA), and cautery without suction (NS). Results Thirty cases were included: 12 in the SE group, 9 in SA, and 9 in NS. The chemical exposure levels were lower than or similar to baseline background concentrations, with the exception of methylene chloride and acetaldehyde. Within the surgical plume, none of the chemical compounds exceeded the corresponding occupational exposure limit (OEL). The mean particulate number concentration in the breathing zone during tonsillectomy was 508 particles/cm3 for SE compared to 1661 particles/cm3 for SA and 8208 particles/cm3 for NS cases. NS was significantly different compared to the other two methods ( P = .0009). Conclusions Although the exposure levels to chemicals were considerably lower than the OELs, continuous exposures to these chemicals could cause adverse health effects to surgical personnel. These findings suggest that the use of a smoke-evacuator pencil cautery or an attentive assistant with handheld suction would reduce exposure levels to the aerosolized particles during routine T&A, compared to the use of cautery without suction.

scholarly journals Air Curtain Dust Removal Device Design and Dust Prevention Strategy in Heading Face

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Xu Huang
Keyword(s):  
Base Plate ◽  
Dust Concentration ◽  
Prevention Strategy ◽  
Previous Model ◽  
Dust Removal ◽  
Device Design ◽  
Airflow Velocity ◽  
Air Curtain ◽  
Total Dust ◽  
Left And Right

Dust protection is a safety guarantee of heading face. The previous model of air curtain research was ideal, and the dust removal effect was rarely studied in the actual dust-producing face. This paper presents a method of air curtain dust removal (ACDR) in the actual heading face. The author designed an air curtain dust removal device (ACDRD). The law of total dust concentration, respiratory dust concentration, and respiratory dust ratio is obtained. The minimum outlet airflow velocity is analyzed using the flat-plane injection theory. The effect of the exhaust fan placement on the dust removal effectiveness is examined. Research indicates the following: The airflow speed at the upper, left, and right sides of the ∩-shaped slot is 17.39 m/s, 12.04 m/s, and 13.66 m/s, respectively. The minimum dust removal speed of the air curtain is 5.48 m/s. The total dust concentration is the highest in the spot of roadheader operator, and the concentration of respiratory dust decreases sharply within 20 m. When the indentation air duct is 2.1 m away from the base plate, the dust-proof effect is better. The results can provide theoretical bases and methods for air curtain analysis of the heading face.

Silicosis in rhinestone-manufacturing workers in South China

2019 ◽  
Vol 69 (7) ◽  
pp. 475-481 ◽  
Author(s):  
C Wen ◽  
X Wen ◽  
R Li ◽  
S Su ◽  
H Xu
Keyword(s):  
South China ◽  
Dust Control ◽  
Control Measures ◽  
Respirable Dust ◽  
Dust Exposure ◽  
Quartz Content ◽  
Total Dust ◽  
Silica Dust ◽  
Exposure Limit ◽  
And Control

Abstract Background Silicosis is caused by long-term exposure to silica dust. Crystal rhinestone workers can be exposed to high levels of silica dust and are at risk of silicosis. Aims To explore silicosis cases, silica dust exposure and control measures in a rhinestone factory in South China. Methods We extracted and analysed data on new silicosis cases reported to China’s occupational disease and occupational health information monitoring system between 2006 and 2012 from a rhinestone factory in South China. We measured the quartz content of bulk dust, static total and respirable dust samples. Results Ninety-eight silicosis cases were reported between 2006 and 2012. The mean duration of silica dust exposure was 9.2 years (range 3–16). Drilling and polishing workers accounted for 96 (98%) of cases. We collected 1479 static samples including 690 total dust and 789 respirable dust samples. Mean dust levels for drilling were 1.01 mg/m3 (range 0.20–3.80) for total dust and 0.51 mg/m3 (range 0.04–1.70) for respirable dust. Mean dust levels for polishing were 0.59 mg/m3 (range 0.20–2.10) for total dust and 0.28 mg/m3 (range 0.08–0.71) for respirable dust. Over a third [289/789 (37%)] of total dust samples and 129/690 (19%) respirable dust samples exceeded the national permissible exposure limit. Conclusion Exposure to silica dust, ineffective dust control measures and inefficient health surveillance may have contributed to the incidence of silicosis in the factory we studied. Identification of silica dust exposure and effective dust control measures would reduce the risk of silicosis in rhinestone workers.

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