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Minerals, Volume 5, Issue 3 (September 2015) – 11 articles

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5161 KiB  
Article
Petrology, Palynology, and Geochemistry of Gray Hawk Coal (Early Pennsylvanian, Langsettian) in Eastern Kentucky, USA
by James C. Hower, Cortland F. Eble, Jennifer M. K. O'Keefe, Shifeng Dai, Peipei Wang, Panpan Xie, Jingjing Liu, Colin R. Ward and David French
Minerals 2015, 5(3), 592-622; https://doi.org/10.3390/min5030511 - 11 Sep 2015
Cited by 70 | Viewed by 6721
Abstract
This study presents recently collected data examining the organic petrology, palynology, mineralogy and geochemistry of the Gray Hawk coal bed. From the Early Pennsylvanian, Langsettian substage, Gray Hawk coal has been mined near the western edge of the eastern Kentucky portion of the [...] Read more.
This study presents recently collected data examining the organic petrology, palynology, mineralogy and geochemistry of the Gray Hawk coal bed. From the Early Pennsylvanian, Langsettian substage, Gray Hawk coal has been mined near the western edge of the eastern Kentucky portion of the Central Appalachian coalfield. While the coal is thin, rarely more than 0.5-m thick, it has a low-ash yield and a low-S content, making it an important local resource. The Gray Hawk coal palynology is dominated by Lycospora spp., and contains a diverse spectrum of small lycopods, tree ferns, small ferns, calamites, and gymnosperms. The maceral assemblages show an abundance of collotelinite, telinite, vitrodetrinite, fusinite, and semifusinite. Fecal pellet-derived macrinite, albeit with more compaction than is typically seen in younger coals, was observed in the Gray Hawk coal. The minerals in the coal are dominated by clay minerals (e.g., kaolinite, mixed-layer illite/smectite, illite), and to a lesser extent, pyrite, quartz, and iron III hydroxyl-sulfate, along with traces of chlorite, and in some cases, jarosite, szomolnokite, anatase, and calcite. The clay minerals are of authigenic and detrital origins. The occurrence of anatase as cell-fillings also indicates an authigenic origin. With the exception of Ge and As, which are slightly enriched in the coals, the concentrations of other trace elements are either close to or much lower than the averages for world hard coals. Arsenic and Hg are also enriched in the top bench of the coal and probably occur in pyrite. The elemental associations (e.g., Al2O3/TiO2, Cr/Th-Sc/Th) indicate a sediment-source region with intermediate and felsic compositions. Rare metals, including Ga, rare earth elements and Ge, are highly enriched in the coal ashes, and the Gray Hawk coals have a great potential for industrial use of these metals. The rare earth elements in the samples are weakly fractionated or are characterized by heavy-REE enrichment, indicating an input of natural waters or probably epithermal solutions. Full article
(This article belongs to the Special Issue Minerals in Coal)
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3483 KiB  
Article
Dynamic Modeling and Real-Time Monitoring of Froth Flotation
by Khushaal Popli, Masih Sekhavat, Artin Afacan, Stevan Dubljevic, Qi Liu and Vinay Prasad
Minerals 2015, 5(3), 570-591; https://doi.org/10.3390/min5030510 - 31 Aug 2015
Cited by 20 | Viewed by 9015
Abstract
A dynamic fundamental model was developed linking processes from the microscopic scale to the equipment scale for batch froth flotation. State estimation, fault detection, and disturbance identification were implemented using the extended Kalman filter (EKF), which reconciles real-time measurements with dynamic models. The [...] Read more.
A dynamic fundamental model was developed linking processes from the microscopic scale to the equipment scale for batch froth flotation. State estimation, fault detection, and disturbance identification were implemented using the extended Kalman filter (EKF), which reconciles real-time measurements with dynamic models. The online measurements for the EKF were obtained through image analysis of froth images that were captured and analyzed using the commercial package VisioFroth (Metsor Minerals). The extracted image features were then correlated to recovery using principal component analysis and partial least squares regression. The performance of real-time state estimation and fault detection was validated using batch flotation of pure galena at various operating conditions. The image features that were strongly representative of recovery were identified, and calibration and validation were performed against off-line measurements of recovery. The EKF successfully captured the dynamics of the process by updating the model states and parameters using the online measurements. Finally, disturbances in the air flow rate and impeller speed were introduced into the system, and the dynamic behavior of the flotation process was successfully tracked and the disturbances were identified using state estimation. Full article
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7482 KiB  
Article
RTRO–Coal: Real-Time Resource-Reconciliation and Optimization for Exploitation of Coal Deposits
by Jörg Benndorf, Cansin Yueksel, Masoud Soleymani Shishvan, Heinrich Rosenberg, Thomas Thielemann, Robert Mittmann, Oliver Lohsträter, Matthias Lindig, Corinna Minnecker, Ralf Donner and Wojciech Naworyta
Minerals 2015, 5(3), 546-569; https://doi.org/10.3390/min5030509 - 25 Aug 2015
Cited by 16 | Viewed by 7033
Abstract
This contribution presents an innovative and integrated framework for real-time-process reconciliation and optimization (RTRO) in large continuous open pit coal mines. RTRO-Coal is currently developed, validated, tested and implemented as part of a multi-national multi-partner European Union funded R&D project. The key concept [...] Read more.
This contribution presents an innovative and integrated framework for real-time-process reconciliation and optimization (RTRO) in large continuous open pit coal mines. RTRO-Coal is currently developed, validated, tested and implemented as part of a multi-national multi-partner European Union funded R&D project. The key concept is to promote a shift in paradigm from intermittent discontinuous to a continuous process monitoring and quality management system in large scale coal mining operations. The framework is based on a real-time feedback control loop linking online data acquired during extraction rapidly with a sequentially up-datable resource model. The up-to-date model is integrated with a real-time optimization of short-term sequencing and production control decisions. Improved decisions are expected to lead to increased resource-and process efficiency and support a sustainable extraction of natural resources. This contribution introduces to the framework, discusses main building blocks and illustrates the value added by the means of selected examples. Full article
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1614 KiB  
Article
An Underground Air-Route Temperature Prediction Model for Ultra-Deep Coal Mines
by Shuai Zhu, Shiyue Wu, Jianwei Cheng, Siyuan Li and Mingming Li
Minerals 2015, 5(3), 527-545; https://doi.org/10.3390/min5030508 - 25 Aug 2015
Cited by 25 | Viewed by 8547
Abstract
Due to modern mining methods deployed in recent years, production of coal mines has been expanded significantly compared to thirty years ago. As a consequence, the mining depth of coal mines is becoming ever deeper. A common world-wide problem that underground coal mines [...] Read more.
Due to modern mining methods deployed in recent years, production of coal mines has been expanded significantly compared to thirty years ago. As a consequence, the mining depth of coal mines is becoming ever deeper. A common world-wide problem that underground coal mines are currently experiencing is the hazard caused by the underground hot environment, which also promotes a great need of reliable mitigation measures to assist mine operators controlling the heat stress for miners as well as maintaining the normal operation of the mine. In this paper, a model for underground air-route temperature prediction in ultra-deep mines based on previous findings was developed. In developing this model, the idea of heat balance was used to establish the temperature calculation equation. Various underground heat sources (air compress, wall oxidation, underground heat, machinery, etc.) are covered in the model to improve the prediction accuracy. In addition, a PC-based numerical tool was also developed to aid users using such a mathematical model. Finally, a few temperature measurements for an ultra-deep underground coal mine were performed to demonstrate the applicability of the proposed mathematical prediction model. Full article
(This article belongs to the Special Issue Advanced Underground Mine Ventilation and Monitoring Systems)
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3743 KiB  
Article
Quantitative XRD Analysis of the Structural Changes of Ba-Exchanged Montmorillonite: Effect of an in Situ Hydrous Perturbation
by Walid Oueslati, Marwa Ammar and Nejmeddine Chorfi
Minerals 2015, 5(3), 507-526; https://doi.org/10.3390/min5030507 - 14 Aug 2015
Cited by 19 | Viewed by 6260
Abstract
The structural changes along the c axis, of the Ba-exchanged montmorillonite (Swy-2-Ba), under variable relative humidity (% RH), is investigated. In this regard, the arrangement, amount and position of both exchangeable cation and the water molecules in the interlamellar space (IS), are evaluated. [...] Read more.
The structural changes along the c axis, of the Ba-exchanged montmorillonite (Swy-2-Ba), under variable relative humidity (% RH), is investigated. In this regard, the arrangement, amount and position of both exchangeable cation and the water molecules in the interlamellar space (IS), are evaluated. This aim is achieved using the X-ray diffraction (XRD) profile modeling approach that consists of comparing experimental and theoretical patterns calculated from structural models. The contributions of the hydration states and the interlayer water amounts, as a function of the % RH, are registered by quantitative XRD investigation. The validated structural models are heterogeneous, suggesting various proportions of layer types at different RH ranges, which means the coexistence of different mixed layer structure MLS packages, exhibiting different proportions of layers with contrasting hydration states. This result is attributed to the orientation of the applied hydration sequence. Indeed, the interlayer water molecule amounts, which led to the appearance of a logic hydration hysteresis, are strongly affected by hydrous perturbation. Full article
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12320 KiB  
Article
Calcification and Diagenesis of Bacterial Colonies
by Ninon Robin, Sylvain Bernard, Jennyfer Miot, Marie-Madeleine Blanc-Valleron, Sylvain Charbonnier and Gilles Petit
Minerals 2015, 5(3), 488-506; https://doi.org/10.3390/min5030488 - 22 Jul 2015
Cited by 19 | Viewed by 9959
Abstract
Evidencing ancient interspecific associations in the fossil record may be challenging, particularly when bacterial organisms have most likely been degraded during diagenesis. Yet, documenting ancient interspecific associations may provide valuable insights into paleoenvironmental conditions and paleocommunities. Here, we report the multiscale characterization of [...] Read more.
Evidencing ancient interspecific associations in the fossil record may be challenging, particularly when bacterial organisms have most likely been degraded during diagenesis. Yet, documenting ancient interspecific associations may provide valuable insights into paleoenvironmental conditions and paleocommunities. Here, we report the multiscale characterization of contemporary and fossilized calcifying bacterial colonies found on contemporary shrimps from Mexico (La Paz Bay) and on 160-Ma old fossilized decapods (shrimps) from the Lagerstätte of La Voulte-sur-Rhône (France), respectively. We document the fine scale morphology, the inorganic composition and the organic signatures of both the contemporary and fossilized structures formed by these bacterial colonies using a combination of electron microscopies and synchrotron-based scanning transmission X-ray microscopy. In addition to discussing the mechanisms of carbonate precipitation by such bacterial colonies, the present study illustrates the degradation of bacterial remains occurring during diagenesis. Full article
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992 KiB  
Article
Market Structure Differences Impacting Australian Iron Ore and Metallurgical Coal Industries
by Kurt Lawrence and Micah Nehring
Minerals 2015, 5(3), 473-487; https://doi.org/10.3390/min5030473 - 22 Jul 2015
Cited by 10 | Viewed by 10003
Abstract
Steelmaking relies on iron ore and metallurgical coal as main ingredients, the trade of which is hypothesized to theoretically change in tandem. However, strong correlation is not evident in historical trade prices of steelmaking inputs. To determine causes to this occurrence, the market [...] Read more.
Steelmaking relies on iron ore and metallurgical coal as main ingredients, the trade of which is hypothesized to theoretically change in tandem. However, strong correlation is not evident in historical trade prices of steelmaking inputs. To determine causes to this occurrence, the market factors that influence the Australian iron ore and metallurgical coal industries were studied. Data was collected over the past decade for worldwide resource production and trade quantities of crude steel, iron ore, and metallurgical coal. The data was analysed to reveal trends, allowing examination of the macroeconomic trade of metallurgical coal and iron ore with relation to worldwide and country specific steel production. It was determined that the influential growth of China’s steel production has spurred the growth of worldwide iron ore demand, which was met with increased production and supply, from Australia. The increased metallurgical coal demand has been met with increased production within China locally. Measures of supply elasticity were created for worldwide iron ore and metallurgical coal trade, where comparisons between Australia’s industries to the relevant greatest competitor were examined. The results, along with respective resource production data, highlighted the elevated competitive position that Australian iron ore producers enjoy compared to metallurgical coal producers. Trade characteristics revealed the different market structures that iron ore and metallurgical coal industries operate in, prompting a discussion of the effects these markets have on the two Australian industries. Full article
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3877 KiB  
Article
Characterization of the Bacterial and Sulphate Reducing Community in the Alkaline and Constantly Cold Water of the Closed Kotalahti Mine
by Malin Bomberg, Mona Arnold and Päivi Kinnunen
Minerals 2015, 5(3), 452-472; https://doi.org/10.3390/min5030452 - 9 Jul 2015
Cited by 16 | Viewed by 5741
Abstract
Drainage from metal-sulphide rich rocks may cause considerable environmental stress in the form of elevated sulphate and heavy metal contamination of the environment. Mine draining effects from closed mines may be abated using indigenous and introduced microbial communities for sulphate reduction and metal [...] Read more.
Drainage from metal-sulphide rich rocks may cause considerable environmental stress in the form of elevated sulphate and heavy metal contamination of the environment. Mine draining effects from closed mines may be abated using indigenous and introduced microbial communities for sulphate reduction and metal precipitation at the mining site. Here we characterized the general and sulphate reducing bacterial (SRB) community of Kotalahti Mine (Finland). The mine was flooded after closure and sulphate reduction and metal precipitation was induced by addition of pig manure sludge into the Vehkankuilu shaft. Water was sampled from Vehkankuilu and Ollinkuilu shafts from depths −10, −30, −70 and −100 m 15 years after the treatment. The water in the shafts differed from each other biologically and geochemically. The shafts are not directly connected except by some fracture zones, and the Ollinkuilu shaft is used as a reference for environmental monitoring. The detected bacterial communities from both shafts contained methylotrophic γ-Proteobacteria, hydrogenotrophic and methylotrophic β-Proteobacteria and fermenting bacterial clades. The concentration of SRB was low, at most 4.0 × 103 dsrB genes·mL−1, and the SRB affiliated with Desulfobulbus and Thermoanaerobacteriales clades. Despite the obvious success of the mine as an in situ bioreactor for increasing water pH and removing sulphate and heavy metals by induced sulphate reduction under suboptimal temperature, only a small portion, less than 0.5%, of the bacterial population in the mine water was SRB. Full article
(This article belongs to the Special Issue Advances in Biohydrometallurgy)
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2391 KiB  
Review
The Confluence of Heavy Metal Biooxidation and Heavy Metal Resistance: Implications for Bioleaching by Extreme Thermoacidophiles
by Garrett Wheaton, James Counts, Arpan Mukherjee, Jessica Kruh and Robert Kelly
Minerals 2015, 5(3), 397-451; https://doi.org/10.3390/min5030397 - 7 Jul 2015
Cited by 74 | Viewed by 13878
Abstract
Extreme thermoacidophiles (Topt > 65 °C, pHopt < 3.5) inhabit unique environments fraught with challenges, including extremely high temperatures, low pH, as well as high levels of soluble metal species. In fact, certain members of this group thrive by metabolizing [...] Read more.
Extreme thermoacidophiles (Topt > 65 °C, pHopt < 3.5) inhabit unique environments fraught with challenges, including extremely high temperatures, low pH, as well as high levels of soluble metal species. In fact, certain members of this group thrive by metabolizing heavy metals, creating a dynamic equilibrium between biooxidation to meet bioenergetic needs and mechanisms for tolerating and resisting the toxic effects of solubilized metals. Extremely thermoacidophilic archaea dominate bioleaching operations at elevated temperatures and have been considered for processing certain mineral types (e.g., chalcopyrite), some of which are recalcitrant to their mesophilic counterparts. A key issue to consider, in addition to temperature and pH, is the extent to which solid phase heavy metals are solubilized and the concomitant impact of these mobilized metals on the microorganism’s growth physiology. Here, extreme thermoacidophiles are examined from the perspectives of biodiversity, heavy metal biooxidation, metal resistance mechanisms, microbe-solid interactions, and application of these archaea in biomining operations. Full article
(This article belongs to the Special Issue Advances in Biohydrometallurgy)
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2465 KiB  
Article
Mineralogical and Geochemical Characteristics of Late Permian Coals from the Mahe Mine, Zhaotong Coalfield, Northeastern Yunnan, China
by Xibo Wang, Ruixue Wang, Qiang Wei, Peipei Wang and Jianpeng Wei
Minerals 2015, 5(3), 380-396; https://doi.org/10.3390/min5030380 - 2 Jul 2015
Cited by 17 | Viewed by 5734
Abstract
This paper reports the mineralogical and geochemical compositions of the Late Permian C2, C5a, C5b, C6a, and C6b semianthracite coals from the Mahe mine, northeastern Yunnan, China. Minerals in the coals are mainly made up of quartz, chamosite, kaolinite, mixed-layer illite/smectite (I/S), pyrite, [...] Read more.
This paper reports the mineralogical and geochemical compositions of the Late Permian C2, C5a, C5b, C6a, and C6b semianthracite coals from the Mahe mine, northeastern Yunnan, China. Minerals in the coals are mainly made up of quartz, chamosite, kaolinite, mixed-layer illite/smectite (I/S), pyrite, and calcite; followed by anatase, dolomite, siderite, illite and marcasite. Similar to the Late Permian coals from eastern Yunnan, the authigenic quartz and chamosite were precipitated from the weathering solution of Emeishan basalt, while kaolinite and mixed-layer I/S occurring as lenses or thin beds were related to the weathering residual detrital of Emeishan basalt. However, the euhedral quartz and apatite particles in the Mahe coals were attributed to silicic-rock detrital input. It further indicates that there has been silicic igneous eruption in the northeastern Yunnan. Due to the silicic rock detrital input, the Eu/Eu* value of the Mahe coals is lower than that of the Late Permian coals from eastern Yunnan, where the detrital particles were mainly derived from the basalt. The high contents of Sc, V, Cr, Co, Ni, Cu, Ga, and Sn in the Mahe coals were mainly derived from the Kangdian Upland. Full article
(This article belongs to the Special Issue Minerals in Coal)
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1026 KiB  
Article
Beneficiation of Low-Grade Phosphate Deposits by a Combination of Calcination and Shaking Tables: Southwest Iran
by Shahram Shariati, Aisan Ramadi and Armin Salsani
Minerals 2015, 5(3), 367-379; https://doi.org/10.3390/min5030367 - 25 Jun 2015
Cited by 21 | Viewed by 8556
Abstract
Three quarters of the world’s phosphate deposits are of sedimentary origin and 75%–80% of those include carbonate gangue. In this study, carbonate sedimentary phosphate deposits of the Lar Mountains of southwest Iran are studied. These deposits consist mainly of calcite, fluorapatite, quartz, kaolinite [...] Read more.
Three quarters of the world’s phosphate deposits are of sedimentary origin and 75%–80% of those include carbonate gangue. In this study, carbonate sedimentary phosphate deposits of the Lar Mountains of southwest Iran are studied. These deposits consist mainly of calcite, fluorapatite, quartz, kaolinite and illite, with an average P2O5 grade of 9%–10% (low-grade). Various pre-processing and processing methods have been developed for concentrating low-grade phosphate up to marketable grade and this study aims to select the optimal method to produce an economically viable grade of phosphate concentrate from low-grade ore. Different concentration methods, including calcination and gravity separation, were applied on samples at both a laboratory and semi-industrial scale (pilot scale). Using an integrated method of calcination (performed in a rotary kiln) and shaking table for concentrating the low-grade phosphate ore, the results show promise at producing grades of 30.77% P2O5 with 60.7%–63.2% recovery. Full article
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