US Coal Research Articles

Resting diffusing capacity and severity of radiographic disease predict gas exchange abnormalities with exercise in former US coal miners.

The US Department of Labor (DOL) does not fund diffusing capacity (DLCO) or metabolic measurements from cardiopulmonary exercise testing (CPET) for coal miners' disability evaluations. Although exercise arterial blood gas testing is covered, many miners are unable to perform maximal tests, and sampling at peak exercise can be challenging. We explored the relationship between resting DLCO, radiographic disease severity, and CPET abnormalities in former US coal miners. We analyzed data from miners evaluated between 2005 and 2015. Multivariable linear and logistic regression analyses were used to examine relationships between percent predicted (pp) forced expiratory volume in 1 s (FEV1pp), DLCOpp, VO2maxpp, A-a oxygen gradient (A-a)pp, dead space fraction (Vd/Vt), disabling oxygen tension (PO2), and radiographic findings of pneumoconiosis. Data from 2015 male coal miners was analyzed. Mean tenure was 28 years (SD 8.6). Thirty-twopercent had an abnormal A-a gradient (>150 pp), 20% had elevated Vd/Vt (>0.33), and 34% a VO2max < 60 pp. DLCOpp strongly predicted a disabling PO2, with an odds ratio (OR) of 2.33 [2.09-2.60], compared to 1.18 [1.08-1.29] for FEV1. Each increase in subcategory of small opacity (simple) pneumoconiosis increased the odds of a disabling PO2 by 42% [1.29-1.57], controlling for age, body mass index, pack-years of tobacco smoke exposure, and years of coal mine employment. DLCO is the best resting pulmonary function test predictor of CPET abnormalities. Radiographic severity of pneumoconiosis was also associated with CPET abnormalities. These findings support funding DLCO testing for impairment and suggest the term "small opacity" should replace "simple" pneumoconiosis to reflect significant associations with impairment.

Thin seams and small mines are associated with higher exposures to respirable crystalline silica in US underground coal mines

ObjectivesPrevious radiologic and histopathologic studies suggest respirable crystalline silica (RCS) overexposure has been driving the resurgence of pneumoconiosis among contemporary US coal miners, with a higher prevalence of severe disease...

Do markets Trump politics? Fossil and renewable market reactions to major political events

AbstractWe investigate the effects of three events with major importance for climate policy on energy sector stocks: the Paris Agreement, the Trump election and presidency, and the Biden election. By combining event studies with impulse‐indicator saturation methods, we show that the Paris Agreement and the election of Mr. Biden benefited renewable industries, while the election of Mr. Trump had negative effects. For fossil fuel industries, the effects were largely the opposite. Despite Trump's efforts to eliminate environmental regulations, his presidency did however witness a decrease in both US coal production and consumption, while natural gas and oil consumption increased.

Assessment of the Respiratory Health of Working US Coal Miners Since 2014-Radiography, Spirometry, and Symptom Assessments.

The aim of the study is to summarize Coal Workers' Health Surveillance Program findings since 2014, focusing on prevalence of radiographic pneumoconiosis and abnormal spirometry by region. Analysis included the most recent Coal Workers' Health Surveillance Program encounter for working miners during October 1, 2014-June 30, 2022. Central Appalachia consists of Kentucky, Virginia, and West Virginia. Pneumoconiosis prevalence was highest among underground miners, with 318 (6.2%) having radiographic evidence of disease. Central Appalachian miners were more likely to have evidence of pneumoconiosis (relative risk = 4.1 [3.4-5.0]) and abnormal spirometry (relative risk = 1.4 [1.2-1.6]) compared with all others. Central Appalachia is a hotspot for pneumoconiosis, as well as for other indicators of respiratory impairment in coal miners. Outreach for occupational respiratory health surveillance should focus on those areas most heavily affected, ensuring that miners are not hindered by perceived or actual barriers to this secondary intervention.

Pathologic Findings in Severe Coal Workers' Pneumoconiosis in Contemporary US Coal Miners.

The pathology of coal workers' pneumoconiosis (CWP) and its most severe form-progressive massive fibrosis (PMF)-in US coal miners has changed in recent years. Severe disease is occurring in younger miners and has been linked to an increase in silica dust exposure. To update the description of the pathologic features of CWP in contemporary miners compared to historical miners. This study is a retrospective expert classification of lung tissue from 85 historical and contemporary coal miners with PMF. Significant pathologic features were scored by using a standardized instrument with consensus achieved for major findings, including newly defined categories of PMF as coal-type, mixed-type, and silica-type. Pathologic features associated with silica dust exposure, including silica-type PMF, mineral dust alveolar proteinosis (MDAP), and immature (early stage) silicotic nodules, were increased in contemporary miners. Detailed descriptions of the pathology of contemporary CWP with illustrative figures are provided. Silica-related pathologies are more common in contemporary miners. Severe forms of CWP can be detected by subtyping PMF lesions (if present) or by identification of mature and immature silicotic nodules, coal mine dust-related alveolar proteinosis, and severe inflammation in coal miners' lungs. Silica-type PMF cases showed significantly higher levels of MDAP than either mixed- or coal-type PMF (P < .001). High profusion of birefringent silica/silicate particles was observed more frequently in cases with immature (early stage) silicotic nodules (P = .04). Severe inflammation was also significantly increased in contemporary miners (P = .03). Our findings underscore the urgent need to revise current exposure limits and monitoring of respirable crystalline silica in US coal mines.

Covid and the coalfield: Covid-19 vaccine hesitance in Wales and Appalachia

BackgroundVaccine hesitancy is a barrier to Covid-19 vaccine uptake and displays a social gradient, compounding health disparities. While social gradients are a vital concept in health, they flatten distinctions between types of disadvantaged community. This paper focuses on vaccine hesitance in post-industrial and de-industrialising coalfields. The social consequences of the decline of coal mining may present barriers to vaccine uptake. MethodsWe ran parallel surveys in Wales (N = 4187) and US states overlapping with central Appalachia (N = 4864), to examine whether vaccine attitudes and uptake varied between areas with different coal mining histories. These surveys were accompanied by qualitative interviews of 36 residents of these coalfields to explore vaccination decisions and triangulate with survey data. ResultsFactor analysis identified four axes of attitudes in the survey data: vaccine confidence, covid scepticism, vaccine individualism, and concerned confusion. These themes were echoed in the interviews. Vaccine confidence was lower; and covid scepticism, vaccine individualism, and concerned confusion higher, in residents of areas of Wales with greater mining extent and where pits closed during certain periods. Residents of former US coal counties had lower vaccine confidence and higher covid scepticism, while those in current coal counties had greater vaccine individualism and concerned confusion. In former US coal counties and Welsh areas where pits closed since 1980, vaccine uptake was lower. Differences could not be explained by respondents’ income and education. In the interviews, norms of social solidarity were often invoked by vaccinated respondents, while unvaccinated respondents did not frame decisions in the context of the industrial history of their areas. DiscussionThe legacy of coal-mining's decline presents barriers to public health campaigns. We show evidence of this across two historically significant coalfields. Attention is needed to avert negative public health consequences of global energy transition.

Historical shift in pathological type of progressive massive fibrosis among coal miners in the USA

BackgroundPneumoconiosis among coal miners in the USA has been resurgent over the past two decades, despite modern dust controls and regulatory standards. Previously published studies have suggested that respirable crystalline...

Leaving in the lead: Priorities for perovskite photovoltaics

The need for moving electricity generation to a sustainable model requires the development of low cost ubiquitous photovoltaics (PVs) to harvest the planet’s primary energy source, the Sun. Building upon the successes of Si-based and CdTe-based PV technologies, PVs with lower-embodied energy and requiring lower carbon dioxide equivalent to produce will be required to meet long-term sustainability goals. In particular, thin-film technologies, such as high-efficiency metal halide perovskite (MHP) PV modules, provide avenues to reduced embodied energy, lower energy payback times, and enabling energy-dense tandems [H. M. Wikoff et al., Joule 6(7), 1710–1725 (2022) and V. Fthenakis, Renewable Sustainable Energy Rev. 13(9), 2746–2750 (2009)]. The ability to improve efficiency and lower energy payback time of next generation thin-film PV modules is a critical foundation for green H2 and electrification more broadly. In this regard, Pb-based MHP-PVs have separated themselves as a result of the high-efficiencies that can be realized across a range of electronic gaps. Questions regarding Pb-based MHP-PVs that are often asked, as the challenges of efficiency and reliability are met, revolve around the “problem” of the Pb content. Specifically, “does Pb toxicity preclude MHP-PV modules from being deployed at the TW scale?” To provide this sense of scale, in 2021, the United States burned 10.5 quads of coal, with 90% of that used for electricity generation. Given the energy content of coal of 29 MJ/kg and a residual lead content in that coal of 30 mg/kg, electricity generation from coal resulted in more lead emitted into the atmosphere than what would be required to produce over 2 TW of MHP-PV name plate capacity (assuming a 20% module efficiency and an ∼700 nm active layer). This amounts to more PV power than has been deployed across all PV technologies and geographies to date. This only includes US coal consumption; the rest of the world would be much larger. This example illustrates the scale of the material usage relative to the energy production. Imagine a power-generation technology that offsets these Pb emissions from coal and essentially sequesters this Pb content between two sheets of impermeable glass. Why should we let Pb’s history of misuse prevent it from being included in next generation PV modules that can enable a sustainable energy future?

Poor adherence to dust, noise and safety regulations predict injury rates in underground coal mines

BackgroundWhile safety in US coal mining has improved over the past two decades, general occupational health research shows that risk of injury varies across individual worksites and is influenced by...

Increased odds of mortality from non-malignant respiratory disease and lung cancer are highest among US coal miners born after 1939

ObjectivesCoal miners suffer increased mortality from non-malignant respiratory diseases (NMRD), including pneumoconioses and chronic obstructive pulmonary disease, compared with the US population. We characterised mortality trends from NMRD, lung cancer...

Pore structure and flow properties of coal with continued bioconversion

Biogenic natural gas is estimated to be 10% of the total natural gas resource in the United States. Significant research advances have been made towards engineering ideal nutrients for optimizing microbial populations that enhance methane generation from coal in laboratory environments. To transition the technique from laboratory to field applications, it is essential to study the geomechanical and flow behavior of coal during the bioconversion process. This study presents the experimental and modeling studies used to estimate permeability changes of coal during continued bioconversion. Several important results are established in this study. First, the capacity of coal to generate methane from bioconversion is not affected by its size, powdered sample versus fractured core. Second, the coal cleat compressibility increases with bioconversion, while the absolute permeability decreases. Third, the rate of bioconversion depends directly on the cleat porosity of coal. Finally, we established that the permeability decreases because of irreducible water saturation before and after the bio-treatment, swelling of coal due to produced methane, CO2 and water, and generation of fines. We propose that irreducible water saturation and swelling would not adversely affect coal permeability in situ given that most US coals are water saturated to begin with. The overall results point to a promising prospect of field application of the technology.

A Study of Respirable Silica in Underground Coal Mines: Particle Characteristics

Respirable crystalline silica is now considered to be a major culprit of resurgent lung disease among US coal miners—especially in central Appalachia—though questions remain regarding the specific circumstances around exposure to it. As part of a larger investigation of dust in 15 US coal mines, a recent study examined the silica content in both the respirable mine dust samples and the samples of respirable dust generated in the laboratory from primary source materials (i.e., coal and rock strata and rock dusting products). It concluded the rock strata that is being drilled for roof bolting or is being cut along with the coal is the most significant source of respirable silica in many mines, which is consistent with the expectations based on other scattered datasets. However, little information is available on the characteristics of respirable silica particles which might be important for understanding the exposure risks better. In the current study, which represents another part of the aforementioned investigation in 15 mines, scanning electron microcopy with energy dispersive X-ray spectroscopy (SEM–EDX) were used to analyze the size and surface condition (i.e., degree of surface-associated clay) of 1685 silica particles identified in 58 respirable mine dust samples. The results indicated that silica is typically finer in locations nearby to drilling and cutting activities than it is in other locations within a mine, but the silica in the Central Appalachian mines is not necessarily finer than it is in the mines in other regions. An analysis of the particle surfaces revealed that respirable silica in coal mines often does not occur as “free”, high-purity particles. Rather, there can be a range of occurrences including silica particles having a thin “occlusion” layer of clay, silica within agglomerates that can also contain other particle types including clays, or even silica ingrained within other particles such as coal.

Why are Silica Dust Exposures and Silica-Related Health Effects Still a Global Concern?

Background and aim Epidemiology studies of workers exposed to silica dust demonstrate that crystalline SiO2 is a multipotential hazard. Research among construction workers, miners, ceramic and brick workers, countertops workers, and sandblasters where respirable silica dust levels has been measured has demonstrated excess risk for silicosis, cor pulmopale, silica-tuberculosis (SiTB), several chronic respiratory conditions, coal workers pneumoconiosis (CWP), several auto-immune diseases, and cancers of the lung and gastro-intestinal tract. Methods Despite knowledge of these links over the past decades, occupational and environmental health professionals have not been able to address three new silica-related health issues. They are silicosis and CWP among US coal miners, severe silicosis and auto-immune ailments among countertop workers; and ongoing risk for SiTB among Africa miners. The author examined the literature for other novel silica-related health risks. Results Current workers and their managers seem to not have sufficient awareness of the occupational hazards of silica dust. There are new silica dust concerns including fracking sand, railroad ballast, and dust control in countertop machining. There are new cancer links with silica, including women and nonsmokers with excess lung cancer; excess lung cancer among patients with CWP; children’s dust exposure in small-scale gold mining; and excess lung diseases and pulmonary cancer among railroad workers. There is need for research on improved silica sampling techniques and protective gear. Pathologists should explore whether silicosis leads to differences in cell characteristics that produce silica-linked lung cancers compared to ‘garden variety’ malignancies. Conclusion Despite promises that global silica problems were controlled, that seems to be countered by excesses of CWP and SiTB that still bedevil the occupational medicine and public health communities. We need more worker education, prevention or regulatory policy, and basic silica biology and pathology to effectively intervene. Keywords Silica health effects, future prevention efforts; improved sampling methods

Group Ties amid Industrial Change

AbstractCoethnics often work in the same industries. How does this ethnic clustering affect individuals’ political loyalties amid industrial growth and decline? Focusing on migrant groups, the author contends that ethnic groups’ distribution across industries alters the political allegiances of their members. When a group is concentrated in a growing industry, economic optimism and resources flow between coethnics, bolstering migrants’ confidence in their economic security and dissuading investments in local political incorporation. When a group is concentrated in a declining industry, these gains dissipate, leading migrants to integrate into out-groups with greater access to political rents. Analyses of immigrants near US coal mines in the early twentieth century support this theory. The article shows how ethnic groups’ distribution across industries shapes the evolution of group cleavages and illuminates how decarbonizing transitions away from fossil fuels may reshape identity conflicts.

Exporting global warming? Coal trade and the shale gas boom

AbstractWe examine the effect of the US shale gas boom on the international trade and consumption of coal and emissions. We estimate a structural model that links the domestic to the international coal market and use it to simulate counterfactual scenarios. Our results show that the total quantity of coal traded around the world in the absence of the boom is essentially the same as the actual. Moreover, the change in total coal consumed worldwide is also small. Although a compositional change towards coal with different heat content could have significant environmental effects, we show that this is not the case either. Hence, US coal exports simply displaced other coal exports without affecting the total CO and SO emissions. Despite the small overall effects, several countries experience a substantial decrease in their imports of US coal and the associated emissions in the absence of the boom.

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

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...

Computational analysis of influence of particle size, oxygen concertation, and furnace temperature on the ignition characteristics of pulverized high ash and high moisture coal particle

Energy is a critical component in any given region's growth. India has the world's fourth-largest coal reserves. Therefore, energy generation from coal-based power plants is still a significant source of power in the country. However, the performance of Indian coals is poor compared to foreign coals such as South African, Indonesian, and US coals due to the high ash and moisture content. Seventy percent of country electricity need is still dependent on coal power even with known negative environmental consequences such as the production of CO2 & greenhouse gases, and air pollution caused by SOx, NOx, coal sludge, coal dust, and by-products of coal combustion. In this work, effect of coal types, particle sizes, and furnace temperatures on the ignition delay time of pulverized coal particle is investigated. In the current study, the ignition delay time of four Indian coals (IS1, IS2, IS3, and IS4), two Indonesian coals (IAS1 and IAS2), and one South African coal (SA1) were examined for particle sizes ranging from 35 to 115 µm, furnace temperature ranging from 1000 to 1700 K, and oxygen concentrations ranging from 12 to 20% in gas. Furthermore, ignition delay analysis of different coal mixtures (Indian and foreign coals mixtures) has also been studied. Numerical analysis of ignition delay time has been performed using MATLAB. Results show that the ignition delay time of coal particles increases with a decrease in furnace temperature and an increase in particle size. Results also show that the Indian coals have a larger ignition delay time than other considered coals, and ignition characteristics of Indian coals can be enhanced by mixing with high-grade ones. An increase in oxygen concentration also reduces the ignition delay time of the coals.

Experimental study on the adverse effect of gel fracturing fluid on gas sorption behavior for Illinois coal

Hydraulic fracturing is an effective technology for coal reservoir stimulation. After fracturing operation and flowback, a fraction of fracturing fluid will be essentially remained in the formation which ultimately damages the flowability of the formation. In this study, we quantified the gel-based fracturing fluid induced damages on gas sorption for Illinois coal in US. We conducted the high-pressure methane and CO2 sorption experiments to investigate the sorption damage due to the gel residue. The infrared spectroscopy tests were used to analyze the evolution of the functional group of the coal during fracturing fluid treatment. The results show that there is no significant chemical reaction between the fracturing fluid and coal, and the damage of sorption is attributed to the physical blockage and interactions. As the concentration of fracturing fluid increases, the density of residues on the coal surface increases and the adhesion film becomes progressively denser. The adhesion film on coal can apparently reduce the number of adsorption sites for gas and lead to a decrease of gas sorption capacity. In addition, the gel residue can decrease the interconnectivity of pore structure of coal which can also limit the sorption capacity by isolating the gas from the potential sorption sites. For the low concentration of fracturing fluid, the Langmuir volume was reduced to less than one-half of that of raw coal. After the fracturing fluid invades, the desorption hysteresis of methane and CO2 in coal was found to be amplified. The impact on the methane desorption hysteresis is significantly higher than CO2 does. The reason for the increasing of hysteresis may be that the adsorption swelling caused by the residue adhered on the pore edge, or the pore blockage caused by the residue invasion under high gas pressure. The results of this study quantitatively confirm the fracturing fluid induced gas sorption damage on coal and provide a baseline assessment for coal fracturing fluid formulation and technology.

Coal characterization and occurrence of rare earth elements in coal and coal-ash of Sohagpur Coalfield, Madhya Pradesh, India

ABSTRACT Coal is a valuable source for power energy as well as for metal contents within it. Coal and its by-product are considered a promising resource for the critical elements and rare earth elements (REEs). The study of REEs in coal is in its infancy. This paper focuses on REEs’ occurrence, qualitative, and quantitative in coal and its by-products (shale coal, shale coal ash, and coal ash) of Sohagpur Coalfield, Madhya Pradesh, India. The collected coal samples were analyzed by scanning electron microscope with energy-dispersive X-ray analysis, inductively coupled plasma mass spectrometry, bomb calorimeter, thermogravimetric analysis, and ultimate analysis. The REEs’ concentration of Sohagpur Coalfield was also compared with the Chinese coal, US coal, and world coal average. The average content of critical REEs for Y is 51.49 ppm, for Nd is 79.34 ppm, for Eu is 2.67 ppm, for Tb is 1.71 ppm, and for Dy is 9.76 ppm in samples. The highest average values of REEs reported for Ce are 58.15 ppm in coal and 187 ppm in coal ash by-products. Coal by-products of the collected samples are a good resource for REEs than the Chinese coal, US coal, and world coal averages.

Don’t sweat the small stuff? Superstitious Organizational Learning from Experience with Near Misses

A near-miss is an event where the possibility of a failure is present but does not materialize. Many organizations in high-hazard industries have recently adopted near-miss learning systems in the hope that their members will learn from such events to prevent significant failures from occurring in the future. The challenge with correctly learning from near misses is that since the event is not a failure, decision makers must recognize that although a negative event did not happen, it might have occurred. If decision makers do not correctly distinguish between successes and near-misses, organizations and their members can systematically take away the wrong lessons from the event and future performance could decline (rather than improve) as experience accumulates. This negative learning pattern, referred to as “superstitious learning,” has been identified in other contexts, but has not been explored in connection to near misses. In addition to exploring the role of near-misses in superstitious learning, we also explore what signals for learning are provided from heterogeneous versus homogenous near-miss experiences. We use data from reportable safety incidents in the US coal mining industry and a behavioral study set in the context of a coal mining decision to test our hypotheses.