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Geochemistry and Mineralogy of Coal-Bearing Rocks
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Geochemistry and Mineralogy of Coal-Bearing Rocks

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Environmental Mineralogy and Biogeochemistry".

Deadline for manuscript submissions: closed (13 August 2021) | Viewed by 41874

Special Issue Editors

Prof. Dr. Monika J. Fabiańska

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Guest Editor
University of Silesia in Katowice, Faculty of Natural Sciences, Institute of Earth Sciences, Będzińska 60, 41-200 Sosnowiec, Poland
Interests: organic geochemistry of fossil fuels and organic matter dispersed in rocks; transformations of coal waste within dumps; organic environmental pollution; emerging pollutants
Special Issues, Collections and Topics in MDPI journals
Dr. Magdalena Misz-Kennan

E-Mail Website
Guest Editor
Faculty of Natural Sciences, Institute of Earth Sciences, University of Silesia in Katowice, Będzińska 60, 41-200 Sosnowiec, Poland
Interests: coal; dispersed organic matter; combustion; coal wastes; self-heating; environment; organic matter in environment
Special Issues, Collections and Topics in MDPI journals
Dr. Justyna Ciesielczuk

E-Mail Website
Guest Editor
Faculty of Natural Sciences, Institute of Earth Sciences, University of Silesia in Katowice, Będzińska 60, 41-200 Sosnowiec, Poland
Interests: mineralogy of burning coal-waste dumps; hydrothermal alteration of magmatic bodies; secondary minerals of the oxidative supergene zone of ore deposits; efflorescences around thermal springs
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

On behalf of Minerals, I would like to invite you to contribute to the Special Issue related to the geochemistry, mineralogy, and petrology of coal-bearing rocks. These rocks, comprising a wide range of sediments with variable content of organic matter, are part of large geological sequences of different coalification. However, coal mining leads to the extraction of large volumes of coal-bearing rocks as well. The only small percentage of these rocks is usually reused as raw material for such purposes as road and building construction. The remaining part of these rocks is deposited in landfills. This practice, which is used all over the world, causes numerous environmental consequences since the reactive organic matter in coal-bearing rocks is susceptible to oxidation, biodegradation, and self-heating. These processes produce organic and inorganic pollutants emitted to the air or leached to waters and soil. Sulphide oxidation forms acidic conditions favouring mobilization of toxic metals from coal-bearing rocks. They together with chlorides, nitrates, and sulphates are leached and present a significant hazard to surface and groundwaters. Long-term storage of coal-bearing rocks affects the landscape of coal-mining regions and endangers inhabitants living in their vicinity.

This Special Issue invites contributions dealing with mineralogical, geochemical, and petrological aspects of these rocks themselves, their formation within a deposit, thermal evolution and secondary processes such as weathering, transformations after storage in landfills, newly formed phases, the impact of coal waste dumping on the environment and human health, the rehabilitation of coal waste landfills, and the recovery of coal waste material.

Prof. Dr. Monika J. Fabiańska
Dr. Magdalena Misz-Kennan
Dr. Justyna Ciesielczuk
Guest Editors

Manuscript Submission Information

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Keywords

  • Mineralogy and geochemistry of coal-bearing rocks
  • Coal-bearing rocks formation, thermal evolution, and secondary processes
  • Coal-bearing rocks transformation within landfills
  • New phases formation
  • Rehabilitation of coal waste landfills and material recovery
  • Impact of coal waste dumping on the environment and human health.

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Related Special Issue

Published Papers (15 papers)

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Research

20 pages, 6947 KiB  
Article
Tectono-Thermal Events of Coal-Bearing Basin in the Northern North China Craton: Evidence from Zircon–Apatite Fission Tracks and Vitrinite Reflectance
by Dongna Liu, Junwei Lin, Anchao Zhou, Fenghua Zhao, Rui Zhou and Yu Zou
Minerals 2022, 12(8), 942; https://doi.org/10.3390/min12080942 - 26 Jul 2022
Cited by 2 | Viewed by 2148
Abstract
In order to further reveal the tectonic activity of the central and northern North China Craton (NCC) since late Paleozoic, the Datong coal-bearing basin was selected as the research object. The tectono-thermal events and uplifting cooling events of the basin were retrieved through [...] Read more.
In order to further reveal the tectonic activity of the central and northern North China Craton (NCC) since late Paleozoic, the Datong coal-bearing basin was selected as the research object. The tectono-thermal events and uplifting cooling events of the basin were retrieved through zircon and apatite fission tracks and vitrinite reflectance measurements. The research shows that the Datong coal-bearing basin experienced three tectono-thermal events with ages of 245–207 Ma (middle–late Triassic), 179 ± 9 Ma (early Jurassic), and 140 Ma to 78 ± 11 Ma (middle–late Cretaceous), respectively. That just coincides with the lamprophyre activity, Kouquan fault activity, and Zuoyun basaltic andesite magmatic activity which surround the Datong coalfield. The basin also experienced three uplift events with the peak ages of 202 ± 18 Ma (late Triassic), 157 ± 7 Ma (late Jurassic), and 45 ± 3 Ma or 36 ± 3 Ma (middle Eocene), respectively. The Datong Permo-Carboniferous and Jurassic coal vitrinite reflectance proved that the average metamorphism temperature is 104–108 °C, even reaching 163–367 °C. The fission track results showed that the paleotemperature was even higher than 170–250 °C from 117 to 282 Ma and 80–120 °C from 20 to 68 Ma, in the Datong coal-bearing basin. The results show that the deep tectonic activities of the NCC were still active in the Mesozoic and even Cenozoic Paleogene. Full article
(This article belongs to the Special Issue Geochemistry and Mineralogy of Coal-Bearing Rocks)
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18 pages, 3922 KiB  
Article
The Kaolinite Crystallinity and Influence Factors of Coal-Measure Kaolinite Rock from Datong Coalfield, China
by Dongna Liu, Yun Zhang, Anchao Zhou, Emmanuel N. Nnachi, Shuting Huo and Qi Zhang
Minerals 2022, 12(1), 54; https://doi.org/10.3390/min12010054 - 30 Dec 2021
Cited by 8 | Viewed by 3918
Abstract
In order to ascertain the kaolinite crystallinity of Carboniferous Permian coal-measure kaolinite rocks, seven groups of fresh samples were collected from below the ground in the Xiaoyu mine, Datong coalfield. Microscopy, X-ray diffraction (XRD), differential thermal analysis (DTA), infrared (IR) spectroscopy and X-ray [...] Read more.
In order to ascertain the kaolinite crystallinity of Carboniferous Permian coal-measure kaolinite rocks, seven groups of fresh samples were collected from below the ground in the Xiaoyu mine, Datong coalfield. Microscopy, X-ray diffraction (XRD), differential thermal analysis (DTA), infrared (IR) spectroscopy and X-ray fluorescence (XRF) spectrometry methods were applied to the samples. The petrographic analysis results show that the kaolinite rocks are characterized as compact, phaneritic, clastic, sand-bearing, sandy and silty types; the kaolinite content in the Shanxi formation and upper Taiyuan formations was more than 95%, while it was 60–90% in the middle and lower Taiyuan formations. Based on the Hinckley index and the features of XRD, DTA and IR of kaolinites, crystallinity was classified as having three grades: ordered, slightly disordered and disordered. The kaolinites’ SiO2/Al2O3 molar ratio was about 1.9–5.7, with a chemical index of alteration (CIA) of about 95.4–99.5. This research suggests that the kaolinite crystallinity correlates positively to its clay mineral content, purity and particle size, which are also related to the SiO2/Al2O3 molar ratio and CIA. The original sedimentary environment and weathering have a direct influence on kaolinite crystallinity, and the existence of organic matter is conducive to the stable existence of kaolinite. The study results have significance for the extraction and utilization of coal-measure kaolinite and the development of kaolinite crystallography and mineralogy. Full article
(This article belongs to the Special Issue Geochemistry and Mineralogy of Coal-Bearing Rocks)
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20 pages, 7384 KiB  
Article
Molecular and Stable Isotope Composition of Pollutants Emitted during Thermal Processes within the Rymer Coal Waste Dump (Upper Silesia, Poland)
by Dariusz Więcław, Krzysztof Jurek, Monika J. Fabiańska, Elżbieta Bilkiewicz, Adam Kowalski, Magdalena Misz-Kennan and Justyna Ciesielczuk
Minerals 2021, 11(10), 1120; https://doi.org/10.3390/min11101120 - 13 Oct 2021
Cited by 4 | Viewed by 1939
Abstract
Twenty-seven gases and sixteen rock wastes from the thermal active Rymer coal waste dump were collected. The composition and origin of gaseous, liquid, and solid pollutants emitted during the self-heating process and the development of these processes with time were established. Gases were [...] Read more.
Twenty-seven gases and sixteen rock wastes from the thermal active Rymer coal waste dump were collected. The composition and origin of gaseous, liquid, and solid pollutants emitted during the self-heating process and the development of these processes with time were established. Gases were subjected to determination of molecular and stable isotope (δ13C and δ2H) composition. Rock-Eval pyrolysis and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) were applied for evaluation of the quantity and molecular composition of pyrolysates released during the heating of rocks in temperatures from 100 to 650 °C. The main products of Py-GC-MS are released between 350 and 650 °C, namely alkanes, aromatic hydrocarbons, and aromatic alcohols. These components were also recorded in Py-GC-MS products of samples collected from the dump surface. Besides the high-molecular-weight organic compounds, in emitted gases CO2, CO, gaseous hydrocarbons, and S-compounds were recorded. The stable isotope data indicated that methane was generated mainly during the low-temperature thermogenic process, but a share of the microbial-originated gas was visible. The source of the CO2 was the oxidation of organic matter. The gaseous S-compounds were products of high-temperature decomposition of sulphides and organic S-compounds. The hydrocarbon and CO contents of the emitted gases proved to be good indicators for tracking of the self-heating processes. Full article
(This article belongs to the Special Issue Geochemistry and Mineralogy of Coal-Bearing Rocks)
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14 pages, 2301 KiB  
Article
Possibilities of Graphitization of Unburned Carbon from Coal Fly Ash
by Zdzisław Adamczyk, Joanna Komorek, Barbara Białecka, Joanna Całus-Moszko and Agnieszka Klupa
Minerals 2021, 11(9), 1027; https://doi.org/10.3390/min11091027 - 21 Sep 2021
Cited by 10 | Viewed by 2734
Abstract
The paper presents the characteristics of products annealing at the temperatures of 2400 and 3000 °C of unburned carbon from coal fly ash in terms of its possible use as a starting material in the graphitization process. An amorphous substance (organic substance) with [...] Read more.
The paper presents the characteristics of products annealing at the temperatures of 2400 and 3000 °C of unburned carbon from coal fly ash in terms of its possible use as a starting material in the graphitization process. An amorphous substance (organic substance) with an admixture of some minerals has been found in samples subjected to graphitization. However, the graphite phase is dominant in products subjected to graphitization. Studies have also shown a diverse grain morphology in individual samples. The presence of plate-shaped and tube-shaped grains was found. As the graphitization temperature of the starting material increases (2400 and 3000 °C), the specific surface area in the graphitization products decreases. The total pore volume in the samples after the graphitization process was significantly lower than the pore volume of active carbons produced from other unburned carbon. Average pore diameter is similar to the pore diameter in active carbons. The reflectance value of the matrix for the sample graphitized at 3000 °C is characteristic for graphite. Unburned carbon from Polish fly ash can be used as the starting material for graphitization. Full article
(This article belongs to the Special Issue Geochemistry and Mineralogy of Coal-Bearing Rocks)
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28 pages, 11814 KiB  
Article
Petrography, Mineralogy, and Geochemistry of Thermally Altered Coal in the Tashan Coal Mine, Datong Coalfield, China
by Xiaoxia Song, Hongtao Ma, Benjamin M. Saalidong and Kaijie Li
Minerals 2021, 11(9), 1024; https://doi.org/10.3390/min11091024 - 21 Sep 2021
Cited by 11 | Viewed by 3494
Abstract
A suite of coal samples near a diabase dike were collected to investigate the petrographic, mineralogical, and geochemical characteristics of thermally altered coal in Datong Coalfield, China. Proximate analysis, vitrinite reflectance measurement, and petrographic analysis were applied to identify and characterize the alteration [...] Read more.
A suite of coal samples near a diabase dike were collected to investigate the petrographic, mineralogical, and geochemical characteristics of thermally altered coal in Datong Coalfield, China. Proximate analysis, vitrinite reflectance measurement, and petrographic analysis were applied to identify and characterize the alteration halo; optical microscope observation, qualitative X-ray diffractometry, and SEM-EDS were applied to study the phases, occurrence, and composition of minerals; XRF, ICP-MS, and AFS were applied to determine concentrations of major and trace elements; and the occurrence modes of elements were studied by correlation and hierarchical cluster analysis as well as SEM-EDS. The results demonstrated that the 3.6 m dike has caused an alteration halo of approximately 2 m in diameter. In addition, the thermally altered coals were characterized by high vitrinite reflectance, low volatile matter, and the occurrence of thermally altered organic particles. Dolomite and ankerite in the thermally altered coal may be derived from hydrothermal fluids, while muscovite and tobelite may be transformed from a kaolinite precursor. The average concentration of Sr in the Tashan thermally altered coal reached 1714 μg/g, which is over 12 times that of the Chinese coal; the phosphate minerals and Sr-bearing kaolinite account for this significant enrichment. The cluster analysis classified elements with geochemical associations into four groups: group 1 and 2 were associated with aluminosilicates, clays, and carbonates and exhibited enrichment in the coal/rock contact zone, indicating that the dike may be the source of the elements; group 3 included P2O5, Sr, Ba, and Be, which fluctuate in coals, suggesting that their concentrations were influenced by multiple-factors; group 4 did not manifest obvious variations in coals, implying that the coal itself was the source. Full article
(This article belongs to the Special Issue Geochemistry and Mineralogy of Coal-Bearing Rocks)
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30 pages, 11737 KiB  
Article
The Disappearance of Coal Seams Recorded in Associated Gangue Rocks in the SW Part of the Upper Silesian Coal Basin, Poland
by Justyna Ciesielczuk, Monika J. Fabiańska, Magdalena Misz-Kennan, Dominik Jura, Paweł Filipiak and Aniela Matuszewska
Minerals 2021, 11(7), 735; https://doi.org/10.3390/min11070735 - 7 Jul 2021
Cited by 6 | Viewed by 2684
Abstract
Coal seams in the Upper Silesian Coal Basin vanish within the Carboniferous Upper Silesian Sandstone Series and below an unconformity marking the Carboniferous top surface. Changes in the geochemical, mineralogical, petrological and palynological characteristics of gangue rocks associated with the vanished seams record [...] Read more.
Coal seams in the Upper Silesian Coal Basin vanish within the Carboniferous Upper Silesian Sandstone Series and below an unconformity marking the Carboniferous top surface. Changes in the geochemical, mineralogical, petrological and palynological characteristics of gangue rocks associated with the vanished seams record what happened. The observed changes could have been caused by (1) coal-seam paleofire, (2) peat combustion, (3) igneous intrusion, (4) metasomatism and/or (5) weathering. Multifaceted research on samples collected at the Jas-Mos mining area, a part of the operating Jastrzębie-Bzie Coal Mine that are representative of different geological settings in the northern and southern parts of the mining area, point to intra-deposit paleofire as the most plausible reason for the disappearance. Biomarkers enabled recognition of differences in heating duration and oxygen access. Coal seams in the south burned quickly with abundant oxygen supply. Seams in the north pyrolyzed for an extended time under conditions of limited oxygen. Though other methods used proved less sensitive, all confirmed low (100–150 °C) paleotemperature heating. Overall, the reason for the local disappearance of the coal seams, making their exploitation difficult and unprofitable, can be assigned to a variety of different processes in a complex overlapping history of variable weathering, heating due to local endogenic fires and, probably, earlier peat combustion. Full article
(This article belongs to the Special Issue Geochemistry and Mineralogy of Coal-Bearing Rocks)
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18 pages, 6345 KiB  
Article
Gold-Bearing Brown Coal Deposits of the Zeya–Bureya Sedimentary Basin (East Russia): Fundamental Model of Formation
by Anatoliy Petrovich Sorokin, Andrey Alexeyevich Konyushok, Valeriy Mikhailovich Kuz’minykh and Sergey Vadimovich Dugin
Minerals 2021, 11(7), 682; https://doi.org/10.3390/min11070682 - 25 Jun 2021
Cited by 7 | Viewed by 2300
Abstract
The primary sources and the conditions for the formation of the Paleogene–Neogene coal-bearing deposits in the Zeya–Bureya sedimentary basin were identified and studied with the help of paleogeographic reconstructions and geochemical analyses. Based on the results obtained, we suggest a new basic model [...] Read more.
The primary sources and the conditions for the formation of the Paleogene–Neogene coal-bearing deposits in the Zeya–Bureya sedimentary basin were identified and studied with the help of paleogeographic reconstructions and geochemical analyses. Based on the results obtained, we suggest a new basic model of element transfer into the coal, involving two mutually complementary processes to account for the introduction and concentration of gold and other trace elements in the sequences investigated. The first process reflects the system in which peatlands were concentrated along the basin’s junction zone and the passive internal residual mountain ranges. The second reflects the junction’s contrast-type (sharp-type) forms conditions along the external mobile mountain-fold frame. The eroded gold particles were transported over 10–20 km as complex compounds, colloids, dispersed particles, and nanoparticles, and remobilized into clastogenic and dissolved forms along the first few kilometers. The release of gold in the primary sources occurred due to weathering of gold-bearing ore zones, followed by transportation of gold by minor rivers to the areas of peat accumulation. This study considered the probability of the accumulation of high concentrations of gold and rare earth elements (REE) in coal due to the introduction of organic and inorganic materials during floods, with episodes of catastrophic events, and volcano–hydrothermal activities. Full article
(This article belongs to the Special Issue Geochemistry and Mineralogy of Coal-Bearing Rocks)
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20 pages, 11635 KiB  
Article
Paleoclimatic and Redox Condition Changes during Early-Middle Jurassic in the Yili Basin, Northwest China
by Hui Chao, Mingcai Hou, Wenjian Jiang, Haiyang Cao, Xiaolin Chang, Wen Luo and James G. Ogg
Minerals 2021, 11(7), 675; https://doi.org/10.3390/min11070675 - 24 Jun 2021
Cited by 5 | Viewed by 2771
Abstract
The Jurassic was mainly a “greenhouse” period characterized by global warming and by significant peat accumulations in some continental basins. However, studies of Jurassic climate and environments have mainly focused on marine records and only a few on terrestrial sediments. Yili Basin, a [...] Read more.
The Jurassic was mainly a “greenhouse” period characterized by global warming and by significant peat accumulations in some continental basins. However, studies of Jurassic climate and environments have mainly focused on marine records and only a few on terrestrial sediments. Yili Basin, a mid-latitude terrestrial basin in present Northwest China, included accumulation of the important recoverable coal seams. In this study, geological data, clay mineral analysis, and palynological assemblages were employed on fine-grained samples from the Su’asugou section in southern Yili Basin. The factors (paleoclimate, depositional conditions, and paleo-vegetation) impacting peat accumulation were investigated. The results suggest that the siliciclastics may have been derived from exposed Carboniferous rocks in a continental arc environment. A warm and humid paleoclimate in the Yili basin dominated during the early-Early Jurassic deposition of the Badaowan Formation and the Middle Jurassic deposition of the Xishanyao Formation. This climate contributed to high sedimentary rates and to a high productivity of peat-forming paleo-vegetation that was preserved under dysoxic conditions. In contrast, during the late-Early Jurassic between these two formations, the Sangonghe Formation was an interval of relatively aridity that included red beds preserved under more hypoxic sedimentary conditions, and with an interruption in peat formation and preservation. Full article
(This article belongs to the Special Issue Geochemistry and Mineralogy of Coal-Bearing Rocks)
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14 pages, 2535 KiB  
Article
Basic Characteristics of Coal Gangue in a Small-Scale Mining Site and Risk Assessment of Radioactive Elements for the Surrounding Soils
by Dun Wu, Yuanyuan Wang, Meichen Wang, Chao Wei, Guangqing Hu, Xiaoli He and Wei Fu
Minerals 2021, 11(6), 647; https://doi.org/10.3390/min11060647 - 18 Jun 2021
Cited by 15 | Viewed by 2570
Abstract
The accumulation/improper treatment of coal gangue will not only lead to waste of land, but also cause environmental pollution. Especially the impact of radioactive elements on the surrounding ecological environment is widely concerned by many scholars. In this study, the concentration of radioactive [...] Read more.
The accumulation/improper treatment of coal gangue will not only lead to waste of land, but also cause environmental pollution. Especially the impact of radioactive elements on the surrounding ecological environment is widely concerned by many scholars. In this study, the concentration of radioactive elements (uranium (U) and thorium (Th)) of small-scale coal gangue mining site and surrounding soil in the northern region of Xieqiao coal mine were tested, the material composition of coal gangue was analyzed via XRF and XRD, the modes of occurrence of U and Th elements were investigated, and their potential ecological risks and ecological effectiveness were evaluated. The results show that the clay minerals with high content in coal gangue are the key minerals for the adsorption of uranium and thorium in coal gangue. The specific activity of two radioactive elements (U and Th) in soil is much lower than that of coal gangue. With the increase of the distance from the soil collection point to the gangue piles and the depth of the soil profile, the specific activities of the two radioactive elements decrease gradually. On the basis of the concentration curve, the range of the radioactive contamination halo of gangue piles is limited (≤30 m), speculating qualitatively that the gangue dump has no significant influence on the radioactivity of the surrounding water. The modes of occurrence of U and Th in coal gangue and soil are altered. According to the index of geo-accumulation, Th is easier to accumulate in soil environment, but Th and U pollution in soil is not obvious. In contrast to U element, the active state of Th element in soil is generally affected by exogenous (coal gangue) export, which may have a potential environmental effects. This study provides a research idea for the investigation of radioactive element pollution to the surrounding soil in small-scale coal gangue plies. Full article
(This article belongs to the Special Issue Geochemistry and Mineralogy of Coal-Bearing Rocks)
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23 pages, 9946 KiB  
Article
The Miocene Lacustrine Chalk from Lignite Bełchatów Deposit (Poland)—Structural and Textural Character and SO2 Sorption Properties in the Fluid Combustion Conditions
by Elżbieta Hycnar, Tadeusz Ratajczak and Magdalena Sęk
Minerals 2021, 11(6), 572; https://doi.org/10.3390/min11060572 - 27 May 2021
Cited by 3 | Viewed by 2302
Abstract
The Miocene lacustrine chalk in the Bełchatów lignite deposit is one of the most important accompanying minerals. It is found in three lithological varieties: white, dark and silicified. It is selectively operated and stored on anthropogenic deposits, representing the mineral resource base. The [...] Read more.
The Miocene lacustrine chalk in the Bełchatów lignite deposit is one of the most important accompanying minerals. It is found in three lithological varieties: white, dark and silicified. It is selectively operated and stored on anthropogenic deposits, representing the mineral resource base. The article presents the results of research on lacustrine chalk from the Szczerców mine excavation and accumulated on the anthropogenic deposit (the Szczerców field external landfill) regarding the possibility of using SO2 sorbent in the fluid combustion technology. It has been shown that primarily the structural and textural parameters of the rock, and to a lesser extent, the CaCO3 content, are responsible for the high efficiency of SO2 sorption. It has been proven that in this type of technology, the presence of carbonised plant matter only seemingly lowers the quality parameters of the raw material. It has a significant impact on the sorption properties, effectively influencing the expansion of porosity and specific surface during thermal decomposition. The expansion of the surface is mainly based on the pores on the border of mesopores and macropores, i.e., pores considered to be sorptive towards SO2. These pores, because they are formed in a lower temperature range than the calcite thermal dissociation process and are connected together to form a system, act as diffusion channels of CO2 from inside and SO2 into the inside of the sorbent grains, intensifying the decarbonisation and SO2 sorption processes. Full article
(This article belongs to the Special Issue Geochemistry and Mineralogy of Coal-Bearing Rocks)
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15 pages, 3954 KiB  
Article
The Occurrence of Selected Radionuclides and Rare Earth Elements in Waste at the Mine Heap from the Polish Mining Group
by Danuta Smołka-Danielowska and Agata Walencik-Łata
Minerals 2021, 11(5), 504; https://doi.org/10.3390/min11050504 - 11 May 2021
Cited by 4 | Viewed by 2198
Abstract
The paper presents the results of research on rare earth elements (REY) and selected radionuclides in barren rocks deposited on a heap at a mine belonging to the Polish Mining Group (the largest producer of hard coal in EU countries). The maximum concentration [...] Read more.
The paper presents the results of research on rare earth elements (REY) and selected radionuclides in barren rocks deposited on a heap at a mine belonging to the Polish Mining Group (the largest producer of hard coal in EU countries). The maximum concentration of REEs determined in silstones was 261.6 mg/kg and in sandstones 221.2 mg/kg. The average uranium and thorium content in silstones was 6.8 mg/kg and 11.6 mg/kg, respectively. On the other hand, the samples of burnt coal shales contain on average 3.5 mg/kg of uranium and 9.7 mg/kg of thorium. In all coal waste samples, the REE values are higher than in hard coal (15.7 mg/kg). Carriers of REY, uranium, and thorium in coal waste are detritic minerals: monazite and xenotime, which are part of the grain skeleton of barren rocks. Coal waste samples are characterized by a variable distribution of REY concentrations as well as a variable content of radionuclides. The 226Ra, 228Ra, and 40K measurements in the investigated samples were performed using the gamma spectrometry technique. The concentrations of the analyzed isotopes differed depending on the mineralogical composition of the investigated samples. The present study results may be important in determining the possibility of utilization of wastes of barren rocks stored in the mine heap and in assessing environmental and radiological hazards. Full article
(This article belongs to the Special Issue Geochemistry and Mineralogy of Coal-Bearing Rocks)
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18 pages, 14944 KiB  
Article
A Petrographic Investigation of the Carboniferous Sequence from the Ibbenbüren Mine: Tracing the Origin of the Coal Mine Drainage
by Diego Bedoya-Gonzalez, Sylke Hilberg, Günther Redhammer and Thomas Rinder
Minerals 2021, 11(5), 483; https://doi.org/10.3390/min11050483 - 30 Apr 2021
Cited by 3 | Viewed by 2729
Abstract
The mine drainage of the Ibbenbüren anthracite coal mine is characterized by exceptionally high concentrations of dissolved iron and sulfate. The elevated position of the coal field with respect to the surrounding area makes the neighboring sediments an unlikely source of these elements. [...] Read more.
The mine drainage of the Ibbenbüren anthracite coal mine is characterized by exceptionally high concentrations of dissolved iron and sulfate. The elevated position of the coal field with respect to the surrounding area makes the neighboring sediments an unlikely source of these elements. Accordingly, it has been hypothesized that interaction between infiltrating rainwater and the fractured overburden is a key process governing the mine drainage chemistry. To test this hypothesis, two full-diameter core samples drilled above the discharging adit of the coal mine were investigated. The methodology combined several analytical techniques to identify and characterize traces of water–rock interaction related to both diagenesis and relatively recent weathering processes along open fractures. The coupled appearance of kaolinite-dickite-illite minerals in weathered and unweathered rock sections was clearly connected to the burial history of the Carboniferous sequence. In contrast, the formation of iron (oxide-) hydroxides together with the presence of oxidized pyrite in weathering profiles along both sides of the fractures was positively related to the geochemical footprint of the coal mine drainage. Thus, open fractures, possibly originated from mining activities, may play a significant role in the drainage chemistry, especially considering the rather poor hydraulic conditions of the overburden. Full article
(This article belongs to the Special Issue Geochemistry and Mineralogy of Coal-Bearing Rocks)
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17 pages, 8070 KiB  
Article
Geochemistry of the Cheremkhovo and Lower Prisayan Formations from the Jurassic Irkutsk Coal-Bearing Basin: Evidence for Provenance and Climate Change in Pliensbachian–Toarcian
by Ekaterina A. Mikheeva, Elena I. Demonterova and Alexei V. Ivanov
Minerals 2021, 11(4), 357; https://doi.org/10.3390/min11040357 - 30 Mar 2021
Cited by 9 | Viewed by 2534
Abstract
The Cheremkhovo formation (Pliensbachian) is the primary coal-bearing formation of the Irkutsk basin, Eastern Siberia. Still, few geochemical studies of the Jurassic sediments of the Irkutsk coal-bearing basin have been conducted, and there are no data on the geochemistry of the coal-bearing formation [...] Read more.
The Cheremkhovo formation (Pliensbachian) is the primary coal-bearing formation of the Irkutsk basin, Eastern Siberia. Still, few geochemical studies of the Jurassic sediments of the Irkutsk coal-bearing basin have been conducted, and there are no data on the geochemistry of the coal-bearing formation itself. This study presents geochemical data for 68 samples from the Cheremkhovo formation and the overlying Lower Prisayan formation. The age of the former has been estimated by U-Pb dating of zircon from a tonstein (altered volcanic ash) layer as Pliensbachian, whereas the age of the latter is estimated as Pliensbachian–Toarcian according to regional stratigraphy. Major oxide and trace element concentrations were obtained using X-ray fluorescence spectrometry. Geochemical indicators showed diversity between the two studied formations. The indicators used show the change in climate conditions, from warm and humid in the Cheremkhovo formation, to hot and arid during the deposition of the lower Prisayan formation. The provenance of the Irkutsk coal-bearing basin was mainly influenced by the source composition, not recycling, and sediments were mainly derived from felsic to intermediate igneous rocks with a mixture of other rock types. Full article
(This article belongs to the Special Issue Geochemistry and Mineralogy of Coal-Bearing Rocks)
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17 pages, 6567 KiB  
Article
Geological Controls on Enrichment of Rare Earth Elements and Yttrium (REY) in Late Permian Coals and Non-Coal Rocks in the Xian’an Coalfield, Guangxi Province
by Fuqiang Zhang, Baoqing Li, Xinguo Zhuang, Xavier Querol, Natalia Moreno, Yunfei Shangguan, Jinming Zhou and Jialong Liao
Minerals 2021, 11(3), 301; https://doi.org/10.3390/min11030301 - 15 Mar 2021
Cited by 8 | Viewed by 2574
Abstract
The highly elevated concentrations of the rare earth elements and yttrium (REY), U, Mo, Se, and Pb in late Permian coals in some coalfields in Guangxi Province, South China, have been widely investigated; however, the mode of occurrence and enrichment mechanism of these [...] Read more.
The highly elevated concentrations of the rare earth elements and yttrium (REY), U, Mo, Se, and Pb in late Permian coals in some coalfields in Guangxi Province, South China, have been widely investigated; however, the mode of occurrence and enrichment mechanism of these critical elements are still under debate. This study investigates the mineralogical and geochemical compositions of coals and non-coal rocks from the Xian’an Coalfield in Guangxi Province to discuss the geological factors influencing the distribution of critical elements. The mineral in the studied coals consists mainly of quartz, and to a lesser extent, muscovite and kaolinite, with a trace amount of anatase. The coals are significantly enriched in REY, Pb, Se, Mo, and U and display the REY–U–Se–Mo–Pb-enrichment horizon (Horizon I) and U–Mo-enrichment horizon (Horizon II) adjacent to the host rocks or partings. The REY, U, Se, and Pb show organic association while Mo is primarily hosted by Fe-sulfides within Horizon I. The U and Mo have a phosphate affinity within Horizon II. Both the input of pyroclastic and epiclastic materials and the leaching of acidic solutions jointly govern the distribution of the REY–U–Se–Mo–Pb-enrichment horizon (Horizon I) and the U–Mo-enrichment horizon (Horizon II). The concentrations of REY in Horizon I exceed the cutoff grade of REY, and, therefore, the coals in the Horizon I can be regarded as promising raw materials of REY. Full article
(This article belongs to the Special Issue Geochemistry and Mineralogy of Coal-Bearing Rocks)
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20 pages, 2785 KiB  
Article
Enrichment Mechanisms of Gallium and Indium in No. 9 Coals in Anjialing Mine, Ningwu Coalfield, North China, with a Preliminary Discussion on Their Potential Health Risks
by Minmin Zhang, Huidi Hao, Lei Tian, Jinxi Wang, Yanheng Li and Yuzhuang Sun
Minerals 2021, 11(1), 64; https://doi.org/10.3390/min11010064 - 11 Jan 2021
Cited by 9 | Viewed by 3054
Abstract
To provide a comprehensive insight into the enrichment mechanism of gallium and indium in No. 9 coals, eighteen samples were collected from Anjialing mine, Ningwu Coalfield, Shanxi Province for coal petrological, mineralogical and geochemical analyses. The results suggested that Ga and In enrichment [...] Read more.
To provide a comprehensive insight into the enrichment mechanism of gallium and indium in No. 9 coals, eighteen samples were collected from Anjialing mine, Ningwu Coalfield, Shanxi Province for coal petrological, mineralogical and geochemical analyses. The results suggested that Ga and In enrichment mainly hosted in the top horizons, with average concentration coefficients of 8.99 and 2.73 respectively, compared with the rest of horizons (2.46 for Ga and 1.69 for In). Source apportionment indicated that Ga and In were mainly derived from bauxite of Benxi Formation in Yinshan Oldland, while In could originate from felsic magmatic rocks in Yinshan Oldland as well. In addition, weak oxidation condition, medium to intensive weathering, transgression and input of terrestrial higher plants had positive effects on Ga and In enrichment. With the rapid expansion of emerging electronics manufacturing, Ga and In, of which potential risks on human health were neglected previously, were recently considered as hazardous elements. Therefore, this paper also discussed the potential pathways that these elements threatened human health. We suggested that potential risks on environment and human health caused by Ga and In enrichment in coals and coal-related products should be taken into account besides their economic value. Full article
(This article belongs to the Special Issue Geochemistry and Mineralogy of Coal-Bearing Rocks)
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