The purpose of this thesis is to examine the potential of a novel method for analysis and characterization of coal mine dust. Respirable dust has long been an industry concern due to the association of overexposure leading to the development occupational lung disease. Recent trends of increased incidence of occupational lung disease in miners, such as silicosis and Coal Workers Pneumoconiosis, has shown there is a need for a greater understanding of the respirable fraction of dust in underground coal mines. This study will examine the development of a comprehensive standard methodology for characterization of respirable dust via thermogravimetric analysis (TGA). This method was verified with laboratory-generated respirable dust samples analogous to those commonly observed in underground coal mines. Results of this study demonstrate the ability of the novel TGA method to characterize dust efficiently and effectively. Analysis of the dust includes the determination of mass fractions of coal and non-coal, as well as mass fractions of coal, carbonate, and non-carbonate minerals for larger respirable dust samples. Characterization occurs through the removal of dust particulates from the filter and analysis with TGA, which continuously measures change in mass with specific temperature regions associated with chemical changes for specific types of dust particulates. Results obtained from the verification samples reveal that this method can provide powerful information that may help to increase the current understanding of the health risks linked with exposure to certain types of dust, specifically those found in underground coal mines. / Master of Science

Inhalation of respirable dust in coal mines is a serious occupational health hazard which can lead to the development of chronic and irreversible lung diseases, such as Coal Worker's Pneumoconiosis (CWP) and Progressive Massive fibrosis (PMF). After the passage of the Federal Coal Mine Health and Safety Act (CMHSA) in the late 1960's the prevalence of CWP among US coal miners decreased. However, since the late 1990's a resurgence of lung diseases has been reported, particularly in central Appalachia. On the other hand, dust monitoring data suggest that concentrations of respirable coal mine dust (RCMD) and crystalline silica have been on a downward trend. This contradiction has prompted keen interest in detailed characterization of RCMD to shed light on dust constituents-and their sources. Such information might help miners understand where and under what conditions specific sources contribute to RCMD, and how dust controls and monitoring could be enhanced to mitigate the exposure to respirable hazards. Respirable dust particles generated in coal mines are generally associated with three primary sources: the coal strata that is mined and generates mostly coal particles that could contribute for lung diseases, the rock strata that is cut along with the coal and generates most of the respirable silica and silicates, and the rock dust products that are the main source of carbonates which could produce respiratory irritations. Thermogravimetric Analysis (TGA) is one of many analytical tools that might be used for dust characterization. Its primary benefit is that it can be used to apportion the total sample mass into three mass fractions (i.e., coal, carbonates, non-carbonates) which should be roughly associated with the primary dust sources (i.e., coal strata, rock dust products, rock strata) in many coal mines. This thesis consists of two main chapters: Chapter 1, outlines the research motivation, recaps the efforts to establish a standard TGA method for RCMD, and shows results of the validation experiments that were performed in the current work to enable application of the TGA method to a large set of RCMD and laboratory-generated dust samples. In Chapter 2, 46 lab-generated samples from primary dust source materials collected in 15 coal mines, and 129 respirable dust samples from 23 US coal mines are analyzed using the TGA method validated in Chapter 1. Results for both sets of samples are presented and the mine samples are interpreted based on sampling location, mining method and region. Additionally, Chapter 3 summarizes recommendations for future work. / Master of Science / The chronic exposure to dust generated in underground coal operations represents a serious health concern among coal miners that can lead to the development of lung diseases such as Coal Workers Pneumoconiosis (CWP or "black lung). Despite of dust compliance monitoring data that have shown that the concentrations of dust have been declining, since the late 1990's the number of US coal miners diagnosed with lung diseases has been increasing, especially in central Appalachia. This contradiction has prompted keen interest in detailed characterization of respirable coal mine dust (RCMD) to shed light on dust constituents-and their sources. Such information might help miners understand where and under what conditions specific sources contribute to RCMD, and how dust controls and monitoring could be enhanced to mitigate the exposure to respirable hazards. Thermogravimetric Analysis (TGA) has been proposed as an alternative approach for dust characterization. Its primary benefit is that it can be used to apportion the total sample mass into three mass fractions (i.e., coal, carbonates, non-carbonates) which should be roughly associated with the primary dust sources (i.e., coal strata, rock dust products, rock strata) in many coal mines. This thesis consists of two main chapters: Chapter 1, outlines the research motivation, recaps the efforts to establish a standard TGA method for RCMD, and shows results of the validation experiments that were performed in the current work to enable application of the TGA method to a large set of RCMD and laboratory-generated dust samples. In Chapter 2, 46 lab-generated samples from primary dust source materials collected in 15 coal mines, and 129 respirable dust samples from 23 US coal mines are analyzed using the TGA method validated in Chapter 1. Results for both sets of samples are presented and the mine samples are interpreted based on sampling location, mining method and region. Additionally, Chapter 3 summarizes recommendations for future work.

In the past several decades there has been an increased interest in sand, dust, and ash particulates ingestion study for gas turbine engine applications. Recently, there has been an increase in commercial and military fleets operating in medium to highly dusty environments, such as areas in Africa, the Middle East, and Asia. Dusty environments can cause blockage in turbine cooling circuits which can lead to early engine maintenance or removals. Ingested debris can melt, forming glassy or molten deposits on various hot section components in gas turbine engines. This thesis evaluates the onset of deposit formation using an experimental rig to perform testing in high temperature environment. In general, deposits on turbine components can affect the operating capacity and the overall operating efficiency of gas turbine engines. Particulate ingestion events can be catastrophic and cost millions of dollars in maintenance and repairs. The experimental work in this thesis focused only on quantifying the initial deposit formation in high temperature environment to aid in the development of resilient engine design and operational diagnostics. Testing was performed using HASTELLOY® X coupons and Arizona Road Dust with main gas flow temperatures between 1050°C and 1100°C. Arizona Road Dust sample with sizing between 2µm and 40µm were used for experimental testing. The sensitivity of the initial deposit formation on cooled HASTELLOY® X coupon surface was investigated by using an inline air heater. Three cooling test conditions: no cooling, 500°C cooling, and 250°C cooling, were used to alter the surface temperature of the coupon during testing. Results from testing indicated cooling test conditions used have a small impact on deposit formation. / Master of Science / In the past several decades there has been an increased interest in sand, dust, and ash particulates ingestion study for gas turbine engine applications. Recently, there has been an increase in commercial and military fleets operating in medium to highly dusty environments, such as areas in Africa, the Middle East, and Asia. Dusty environments can cause blockage in turbine cooling circuits which can lead to early engine maintenance or removals. Ingested debris can melt, forming glassy or molten deposits on various hot section components in gas turbine engines. This thesis evaluates the onset of deposit formation using an experimental rig to perform testing in high temperature environment. In general, deposits on turbine components can affect the operating capacity and the overall operating efficiency of gas turbine engines. Particulate ingestion events can be catastrophic and cost millions of dollars in maintenance and repairs. The experimental work in this thesis focused only on quantifying the initial deposit formation in high temperature environment to aid in the development of resilient engine design and operational diagnostics. Testing was performed using HASTELLOY® X coupons and Arizona Road Dust with main gas flow temperatures between 1050°C and 1100°C. Arizona Road Dust sample with sizing between 2µm and 40µm were used for experimental testing. The sensitivity of the initial deposit formation on cooled HASTELLOY® X coupon surface was investigated by using an inline air heater. Three cooling test conditions: no cooling, 500°C cooling, and 250°C cooling, were used to alter the surface temperature of the coupon during testing. Results from testing indicated cooling test conditions used have a small impact on deposit formation.

Windblown dust remains a persistent problem within South African urban and peri-urban areas due to the prevailing dry climatic conditions, extensive surface mining and mineral processing. Despite deposition monitoring guidelines and national dust regulations, South Africa still has persistent dust problems in especially gold mining districts. The main aim of the research is to critically evaluate all the potential challenges within dust management which could be responsible for persistent dust problems within gold mining regions of South Africa. The research methodology included a literature review to provide important information regarding the requirements for successful dust management internationally. Data were gathered by using the survey method through questionnaires and interviews as this type of survey method allows for descriptive reporting where respondents provide information on their attitudes and perceptions. In total 37 questionnaires were distributed among two district municipalities, seven gold mining companies, ten interested and affected parties including two non-governmental organizations, as well as five specialists. A total response rate of 81.1 % was achieved. The results of the questionnaires revealed that the most significant challenges to dust management within gold mining regions of South Africa are the following: monitoring networks; monitoring methods; deposition standards; financial provisions; technical skills and capacity; lack of specific dust management plans within air quality management plans; limited regulation and enforcement; limited information and participation of government, lack of participation of interested and affected parties as well as specialists‟ expertise. All the challenges identified were then successfully linked back to the referenced literature from which the challenges were initially derived. The main aim of this research was thus successfully completed by initially identifying the challenges facing dust management within gold mining regions of South Africa and then critically evaluating them and making recommendations. / M. Environmental Management, North-West University, Potchefstroom Campus, 2014

Title from PDF of title page. / Document formatted into pages; contains 48 pages. / Thesis (M.S.P.H.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: International standards establish criteria for size-selective aerosol sampling for industrial hygiene. Commercially available aerosol samplers are designed to conform to these criteria. This study uses semi-monodispersed aerosols generated in a vertically aligned test chamber to compare the performance of three commercially available respirable dust samplers, one of which can, in addition, simultaneously sample for thoracic and inhalable dust fractions. Comparison methods are used to calculate a theoretical fractional value based on the appropriate sampling conventions of the total dust concentration and size distribution of test materials. Performance of actual samplers can be conducted by comparing observed results to the theoretical value. Results show the design of the test chamber and use of fused aluminum oxide is appropriate to conduct simplified performance verification tests for inhalable and respirable dust samplers. / ABSTRACT: This study showed the TSI RespiCon followed the inhalable and respirable conventions closely, but results for the thoracic fraction required the use of a correction factor. The SKC aluminum cyclone tended to undersample the respirable fraction, while the BGI CAS4 cyclone and the TSI RespiCon appear to most closely follow the convention. Improved selection of test material and characterization of particle sizes are recommended to further develop this method of performance verification. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.

Windblown dust remains a persistent problem within South African urban and peri-urban areas due to the prevailing dry climatic conditions, extensive surface mining and mineral processing. Despite deposition monitoring guidelines and national dust regulations, South Africa still has persistent dust problems in especially gold mining districts. The main aim of the research is to critically evaluate all the potential challenges within dust management which could be responsible for persistent dust problems within gold mining regions of South Africa. The research methodology included a literature review to provide important information regarding the requirements for successful dust management internationally. Data were gathered by using the survey method through questionnaires and interviews as this type of survey method allows for descriptive reporting where respondents provide information on their attitudes and perceptions. In total 37 questionnaires were distributed among two district municipalities, seven gold mining companies, ten interested and affected parties including two non-governmental organizations, as well as five specialists. A total response rate of 81.1 % was achieved. The results of the questionnaires revealed that the most significant challenges to dust management within gold mining regions of South Africa are the following: monitoring networks; monitoring methods; deposition standards; financial provisions; technical skills and capacity; lack of specific dust management plans within air quality management plans; limited regulation and enforcement; limited information and participation of government, lack of participation of interested and affected parties as well as specialists‟ expertise. All the challenges identified were then successfully linked back to the referenced literature from which the challenges were initially derived. The main aim of this research was thus successfully completed by initially identifying the challenges facing dust management within gold mining regions of South Africa and then critically evaluating them and making recommendations. / M. Environmental Management, North-West University, Potchefstroom Campus, 2014

Call number: LD2668 .T4 1979 C59 / Master of Science

I have developed a new general-purpose deterministic 2D radiative transfer code for astrophysical dusty environments named LELUYA (www.leluya.org). It can provide the solution to an arbitrary axially symmetric multi-grain dust distribution around an arbitrary heating source. By employing a new numerical method, the implemented algorithm automatically traces the dust density and optical depth gradients, creating the optimal unstructured triangular grid. The radiative transfer equation includes dust scattering, absorption and emission. Unique to LELUYA is also its ability to self-consistently reshape the sublimation/condensation dust cavity around the source to accommodate for the anisotropic diffuse radiation. LELUYAs capabilities are demonstrated in the study of the asymptotic giant branch (AGB) star IRC+10011. The stellar winds emanating from AGB stars are mostly spherically symmetric, but they evolve into largely asymmetric planetary nebulae during later evolutionary phases. The initiation of this symmetry breaking process is still unexplained. IRC+10011 represents a rare example of a clearly visible asymmetry in high-resolution near-infrared images of the circumstellar dusty AGB wind. LELUYA shows that this asymmetry is produced by two bipolar cones with 1/r0.5 density profile, imbedded in the standard 1/r2 dusty wind profile. The cones are still breaking though the 1/r2 wind, suggesting they are driven by bipolar jets. They are about 200 years old, thus a very recent episode in the final phase of AGB evolution before turning into a proto-planetary nebula, where the jets finally break out from the confining spherical wind. IRC+10011 provides the earliest example of this symmetry breaking thus far.

No description available.

Mining operations, including crushing, grinding, smelting, refining, and tailings management, are a significant source of airborne metal and metalloid contaminants such as As, Pb, Cd and other potentially toxic elements. Dust particles emitted from mining operations can accumulate in surrounding soils, natural waters and vegetation at relatively high concentrations through wind and water transport. Human exposure to the dust can occur through inhalation and, especially in the case of children, incidental dust ingestion, particularly during the early years when children are likely to exhibit pica. Furthermore, smelting operations release metals and metalloids in the form of fumes and ultra-fine particulate matter, which disperses more readily than coarser soil dusts. Of specific concern, these fine particulates can be transported to the lungs, allowing contaminants to be transferred into the blood stream. The main aim of this research is to assess the role of atmospheric aerosol and dust in the transport of metal and metalloid contaminants from mining operations to assess the deleterious impacts of these emissions to ecology and human health. In a field campaign, ambient particulates from five mining sites and four reference sites were examined utilizing micro-orifice deposit impactors (MOUDI), total suspended particulate (TSP) collectors, a scanning mobility particle sizer (SMPS), and Dusttrak optical particle counters for an understanding of the fate and transport of atmospheric aerosols. One of the major findings from size-resolved chemical characterization at three mining sites showed that the majority of the contaminant concentrations were found in the fine size fraction (<1 micrometer). Further, metal and metalloids (e.g. As, Cd, and Pb) around smelting activities are significantly enriched in both the coarse and fine size fraction when compared to reference sites. Additionally, with dust events being a growing concern because of predicted climate change and mine tailings being a significant source for dust, high wind conditions around mine tailings were studied for dust generation. Relative humidity was found to play an important predicting role in atmospheric dust concentration. More generally, findings indicate mining activities remain a serious threat to human health and ecology despite the regulations in place to protect from their pollution.