James C Hower

• PhD
• Group Leader at University of Kentucky

United States heavy reliance on imports of critical minerals (CMs), including rare earth elements (REEs), underscores the importance of development of domestic sources. The study objective was to quantify CM and REE concentrations in coals in the US Gulf Coast region. CM and REE concentrations were measured for 118 samples from outcrops and 14 mine...

The mechanical behavior and elastic anisotropy of coal under stress are critical to understanding its structural integrity and performance in subsurface environments. Despite its significance, limited research has systematically analysed the elastic anisotropic responses of coals under such conditions. This study investigates the elastic anisotropy...

In the United States, more than 2 Gt of coal combustion residuals (i.e., coal ash) are stored in hundreds of disposal units. Recent federal regulations mandate the closure or retrofitting of most coal ash impoundments, presenting significant challenges for waste management. These regulatory pressures also present opportunities to reuse coal ash. Ho...

The Middle Pennsylvanian, Langsettian sub-stage Clintwood coal, along with its correlatives, was one of the more important energy resources in eastern Kentucky. The coal thickens from the NE-SW-trending Belfry anticline in central Pike County to the southeast, towards the Virginia-Kentucky border. Much of the thickness increase is in the bright lit...

The mineralogy, thermal behaviour, physicochemical characteristics, and organic petrographic composition of Cretaceous coals from the Benue Trough were examined for their quality, paleo-depositional environment, and the factors that control their coal-bearing formations. Seven coal samples were obtained from the Lower, Middle, and Upper Benue Troug...

The renewable energy industry is heavily reliant on rare earth elements, underscoring the need to develop resources and production. The objective of this work was to estimate coal ash resources and potential for extraction of rare earth elements using data for the US. Data on spatiotemporal variability in coal ash resources and disposition were com...

The fuel, bed ash, and fly ash were sampled from a circulating fluidized bed combustion (CFBC) unit at two times. The first sampling was a high-sulfur (S) coal-only run, and the second sampling coincided with an experimental burn of up to 10% switchgrass (Panicum virgatum) pressed pellets mixed with a highS coal. The latter blend had a higher moist...

The chemistry and petrology of fly ash are controlled by a number of factors: (1) chemistry of the feed coal (and added fuels, such as petroleum coke, tires, biomass, etc.), (2) particle size of the fuel feed (controlled by pulverized fuel vs. cyclone combustion, maintenance of pulverizers, etc.), (3) design of the boiler and pollution-control syst...

Uranium and thorium are part of the mineral assemblages within coals. Uranium can also occur in organic associations, particularly in low-rank coals. While the average U concentration in coals is 2.9 ppm for low-rank coals and 1.9 ppm for bituminous and higher rank coals, high concentrations are known from certain low-rank and thin coals and from c...

Derived through the thermochemical conversion of biomass, biochar is a carbon-rich substance recognized for its significance in environmental applications and sustainable agriculture. As interest in its utilization continues to rise, it becomes crucial to comprehend how the source material and pyrolysis parameters influence the properties of biocha...

Nitrogen is one of the most important elements and mainly occurs as organic forms in coal, and in a few cases, in an inorganic form. Organic nitrogen in coal is mainly derived from the proteins of plants and micro-organisms but sources of inorganic nitrogen remain controversial. One hypothesis for the source of inorganic nitrogen is the organic mat...

Second Miocene Seam Complex (2nd MFK; germ.: 2. Mioz¨aner Fl¨ozkomplex) holds many in-situ, not permineralised fossil tree stumps and trunks with high-cellulose contents. The state of preservation of a set of in-situ fossil trees (Taxodioxylon cryptomerioides, Sciadopityoxylon wettsteinii, and Quasisequoioxylon piskowitzense) collected from three o...

The Cenozoic-age Makum coal from northeastern India offers numerous research opportunities because of its diverse geochemical and geological characteristics. Due to its high sulfur content, the coal has been found to be less useful for industrial purposes. It can, however, serve as a hub for ongoing research on coal-based derivative products. The a...

Considering global market trends and concerns about climate change and sustainability, increased biomass use for energy is expected to continue. As more diverse materials are being utilized to manufacture solid biomass fuels, it is critical to implement quality assessment methods to analyze these fuels thoroughly. One such method is reflected light...

Previously, proof-of-concept studies have demonstrated that rare-earth elements (REEs) can be preferentially extracted from coal fly ash (CFA) solids using a recyclable ionic liquid (IL), betainium bis(trifluoromethylsulfonyl)imide ([Hbet][Tf2N]). When the suspension of aqueous solution—IL-CFA—is heated above 65 °C, the majority of REEs will separa...

In the search for rare earth and other critical elements in coal measures, the coals are emphasized with lesser consideration for the accompanying rocks. In this investigation, the focus is on a lanthanide-rich, 315–317 Ma (after Machlus et al., Chemical Geology, 539, art. no. 119485, 2020) volcanic ash-fall trachyandesite to trachyte tonstein whic...

Tonstein layers are found worldwide in the Permo‐Carboniferous coal‐bearing strata. This study investigates the geochronology, mineralogy, and geochemistry of four tonstein samples from the Permo‐Carboniferous Benxi Formation, Ordos Basin, North China Craton (NCC). The typical features of the studied tonsteins include thin beds, lateral continuity,...

REEs play a pivotal role in the manufacturing of numerous industrial, defense, consumer, and aviation-related gadgets. As many primary sources of REEs are either exhausted or depleted, coal can be a good secondary source of REEs in the near future. The traditional thermo-chemical processes to extract REEs are expensive and detrimental to the enviro...

In this paper, heavy metals (i.e., V, Cr, Co, Cu, Zn, Cd, Pb, and Sb) in soils from a tannery waste lagoon, Hebei, north China were investigated. Element concentrates were determined by a portable X-ray fluorescence in situ and an inductively coupled plasma mass spectrometry in the lab. Two sets of indexes, including geological accumulation index,...

Coal associated with site 31CR314, Queen Anne’s Revenge/La Concorde (1718) was investigated to identify a possible source. The coal ranges from low volatile bituminous, through anthracite, to meta-anthracite. Although the eastern US anthracite sources were not known at that time, several sources, including coalfields in Ireland and Portugal, match...

The Middle Jurassic Yan'an Formation in the Ordos Basin (North China) is an important coal-bearing succession. Twenty coal samples and four samples of silty mudstones were collected from Coal Seam 2 of the Yan'an Formation in order to determine major, trace and rare earth elements; moreover, the geochemistry of the rare earth elements, and in parti...

Quantitative characteristics and sizes of nanoparticles (NPs) in coal fly ash (CFA) produced in coal-fired power plants as a function of coal type and plant design will help reveal the NP emission likelihood and their environmental implications. However, little is known about how combustion conditions and types of coal regulate the NP abundance in...

The mechanisms and controls of the Middle-Late Miocene paleoenvironmental evolution of the northeastern Tibetan Plateau remain elusive. Here, we present an integrated multiproxy study of total organic carbon isotopes, lipid biomarkers, petrographic components and micropaleontological records in the well-dated Xigou section of the Xunhua Basin. Our...

Reported are seminal results of a systematic application of infrared spectrometry to a succession of coal seams in a Carboniferous basin from Sydney Coalfield, Nova Scotia, Canada. Fifty-four lithotypic vitrain samples from ten successive coal seams were analyzed by solid-state (potassium-bromide pellet method) Fourier transform infrared spectrosco...

Coal is a remarkably complex combination of macerals and minerals and inorganic elements in organic associations plus liquids, gases, and semi-solid organics, all overprinted by coal metamorphism. The proper characterization of coal is necessary for academic research on coal origins and utilization and for the current and future industrial utilizat...

The Middle Pennsylvanian Duckmantian-age Fire Clay coal in the vicinity of Inez, Martin County, Kentucky, USA, is about 80-km northeast of the intensely studied Fire Clay coal in central eastern Kentucky. The moderate-ash, high-S, high volatile B bituminous Martin County Fire Clay coal does not have an obvious volcanic ash parting, one of the major...

This study has focused on petrography, geochemistry, radiochemical, and leaching properties of coal combustion residues (CCRs), their leachates and nearby waters from the Barapukuria coal-fired power-plant to evaluate the potential environmental impacts and human health hazards for the first in Bangladesh. The CCRs, used in this study are predomina...