http://www.mdpi.com/journal/minerals Latest open access articles published in Minerals at http://www.mdpi.com/journal/minerals http://www.mdpi.com/2075-163X/3/2/192 Documentation of contaminant source and dispersal pathways in riverine environments is essential to mitigate the potentially harmful effects of contaminants on human and ecosystem health, and is required from a legal perspective (particularly where the polluter pays principle is in effect) in assessing site liability. Where multiple natural and/or anthropogenic sources exist, identification of contaminant provenance has proven problematic, and estimated contributions from a specific source are often the subject of judicial debate. The past, current, and future use of geochemical and isotopic tracers in environmental forensic investigations of contaminant provenance, transport, and fate are analyzed herein for sediment-associated trace metals in riverine environments, particularly trace metals derived from mining and refining operations. The utilized methods have evolved significantly over the past four decades. Of primary significance has been the growing integration of geomorphic and stratigraphic techniques with the use of an increasing number of geochemical tracers including stable isotopes. The isotopes of Pb have been particularly well studied, and have been applied to a wide range of environmental media. Advances in analytical chemistry since the early 1990s have allowed for the precise characterization of other non-traditional stable isotopic systems within geological materials. The potential for using these non-traditional isotopes as tracers in river systems has yet to be adequately explored, but a number of these isotopes (e.g., Cd, Cu, Cr, Hg, Sb, and Zn) show considerable promise. Moreover, some of these isotopes (e.g., those of Cu, Cr, and Hg) may provide important insights into biogeochemical cycling processes within aquatic environments. This review suggests that future environmental forensic investigations will be characterized by an interdisciplinary approach that combines the use of multiple geochemical tracers with detailed stratigraphic, geomorphic, and hydrologic data, thereby yielding results that are likely to withstand the scrutiny of judicial review. Minerals 2013-05-16 3 2 Review 10.3390/min3020192 192 246 2075-163X 2013-05-16 doi: 10.3390/min3020192 Jerry Miller http://www.mdpi.com/2075-163X/3/2/165 Extremely Re-rich molybdenite occurs with pyrite in sodic–calcic, sodic–sericitic and sericitic-altered porphyritic stocks of granodioritic–tonalitic and granitic composition in the Sapes–Kirki–Esymi, Melitena and Maronia areas, northeastern Greece. Molybdenite in the Pagoni Rachi and Sapes deposits is spatially associated with rheniite, as well as with intermediate (Mo,Re)S2 and (Re,Mo)S2 phases, with up to 46 wt % Re. Nanodomains and/or microinclusions of rheniite may produce the observed Re enrichment in the intermediate molybdenite–rheniite phases. The extreme Re content in molybdenite and the unique presence of rheniite in porphyry-type mineralization, combined with preliminary geochemical data (Cu/Mo ratio, Au grades) may indicate that these deposits have affinities with Cu–Au deposits, and should be considered potential targets for gold mineralization in the porphyry environment. In the post-subduction tectonic regime of northern Greece, the extreme Re and Te enrichments in the magmatic-hydrothermal systems over a large areal extent are attributed to an anomalous source (e.g., chemical inhomogenities in the mantle-wedge triggered magmatism), although local scale processes cannot be underestimated. Minerals 2013-05-02 3 2 Review 10.3390/min3020165 165 191 2075-163X 2013-05-02 doi: 10.3390/min3020165 Panagiotis Voudouris Vasilios Melfos Paul Spry Luca Bindi Robert Moritz Melissa Ortelli Tamara Kartal http://www.mdpi.com/2075-163X/3/2/145 Whole-body vibration is a significant health risk for between 4% and 7% of the work force in North America. In addition, many factors compound the health risks of heavy machinery operators. For example, twisted trunk and neck postures stiffen the spine and increase the transmission of vibration to the head. Similarly, workers adopt awkward postures in order to gain appropriate lines of sight for machine operations. Although the relative contribution of these various issues can be evaluated in field studies and models, we propose that virtual reality is a powerful medium for investigating issues related to health and safety in mining machine operators. We have collected field data of posture and vibration, as well as visual environment, for a forklift operating in a warehouse. This paper describes the process and outcome of this field data collection, and provides a discussion on the next steps to develop and test the virtual reality model to enable laboratory testing. Our ongoing studies will evaluate the interplay between posture and vibration under conditions replicating routine heavy machinery operations, such as underground mining. Minerals 2013-04-15 3 2 Article 10.3390/min3020145 145 164 2075-163X 2013-04-15 doi: 10.3390/min3020145 James Dickey Tammy Eger Ryan Frayne Giselle Delgado Xiaoxu Ji http://www.mdpi.com/2075-163X/3/2/121 Tungsten mineralization in hydrothermal quartz veins from the Nyakabingo,Gifurwe and Bugarama deposits in central Rwanda occurs as the iron-rich endmember ofthe wolframite solid solution series (ferberite) and in the particular form of reinite, whichrepresents a pseudomorph of ferberite after scheelite. Primary ferberite, reinite and latesecondary ferberite are characterized by their trace element chemistry and rare earthelement patterns. The replacement of scheelite by ferberite is also documented in the traceelement composition. Primary ferberite shows high Mg, Zn, Sc, V, Nb, In and Snconcentrations, but very low Ca, Pb, Sr and Ba contents. Reinite and late secondaryferberite display an uncommon trace element composition containing high concentrationsof Ca, Pb, Sr, Ba, As and Ga, but very low levels in Sn, Zr, Hf, In, Ti, Sc, Nb, Ta, Mg andZn. Late secondary ferberite replacing primary ferberite is characterized by additionalenrichments in Bi, Pb, As and Sb. The rare earth element patterns of reinite and secondaryferberite are also similar to hydrothermal scheelite. The formation of the tungsten depositsin central Rwanda is interpreted to be epigenetic in origin, and the hydrothermalmineralizing fluids are related to the intrusion of the G4-granites. Minerals 2013-04-02 3 2 Article 10.3390/min3020121 121 144 2075-163X 2013-04-02 doi: 10.3390/min3020121 Simon Goldmann Frank Melcher Hans-Eike Gäbler Stijn Dewaele Friso Clercq Philippe Muchez http://www.mdpi.com/2075-163X/3/1/94 Agpaitic nepheline syenites at the Norra Kärr Alkaline Complex, southern Sweden, are rich in zirconium and rare-earth elements (REE), which are mainly accommodated in eudialyte-group minerals (EGM). Norra Kärr hosts three compositionally distinct groups of EGM, which are complex zirconosilicates. Analyses of EGM by electron beam energy-dispersive (SEM-EDS) and wavelength-dispersive (WDS-EMP) X-ray microanalysis are presented and compared, complemented by whole-rock analyses. The SEM-EDS and WDS-EMP methods produce comparable results for most elements. Considering that most SEM instruments have a user-friendly EDS system, it is a useful tool for reconnaissance work in research and especially in exploration-related studies. The EGM evolved markedly from an initial Fe-rich and REE-poor, but HREE-dominated variety, to an intermediate Fe-Mn and HREE-rich one, and to a final Mn- and LREE-rich variety, which occur in rocks classified as lakarpite and grennaite. Based on the Mn/(Fe+Mn) ratios of the EGM, this trend is interpreted as a result of magmatic evolution. The threefold diversity of EGM presented in this work is much broader than has previously been documented. Minerals 2013-03-20 3 1 Article 10.3390/min3010094 94 120 2075-163X 2013-03-20 doi: 10.3390/min3010094 Axel Sjöqvist David Cornell Tom Andersen Muriel Erambert Mattias Ek Magnus Leijd http://www.mdpi.com/2075-163X/3/1/82 Gold has been found in the Cyprus-type volcanogenic massive sulfide ore (VMS) deposits of Corchia ophiolite (Parma province, Italy) in the Cantiere Donnini, Speranza and Pozzo mining sites. At Cantiere Donnini and Speranza, the mineralization occurs at the contact between pillow lava and sedimentary rocks. The Pozzo mineralization is hosted by a serpentinite. Concentrations of gold up to 3070 ppb have been reported for the Cantiere Donnini and up to 6295 ppb in the Pozzo mine. According to the field relationships, gold composition, mineralogical assemblage and sulfur isotope data, we can conclude that two different types of gold mineralization have been recognized in the Corchia ophiolite: (1) formed at low temperature in submarine environment (Cantiere Donnini and Speranza) and (2) formed at high temperature in the oceanic mantle (Pozzo) by segregation of an immiscible sulfide liquid. Minerals 2013-03-05 3 1 Article 10.3390/min3010082 82 93 2075-163X 2013-03-05 doi: 10.3390/min3010082 Zaccarini Federica Giorgio Garuti http://www.mdpi.com/2075-163X/3/1/73 Early stages of sheath formation by Leptothrix sp. strain OUMS1 and its derivative sheathless mutant grown in media with or without Fe were examined by light and electron microscopy. Results showed that the initial parallel arrangement of fibrils excreted from the cells holds a key for subsequent construction of the sheath frame and that aqueous-phase Fe interacts with excreted fibrils whether fibrils are parallel-arranged or simply-intermingled. Minerals 2013-02-22 3 1 Article 10.3390/min3010073 73 81 2075-163X 2013-02-22 doi: 10.3390/min3010073 Hiromichi Ishihara Tomoko Suzuki Hideki Hashimoto Hitoshi Kunoh Jun Takada http://www.mdpi.com/2075-163X/3/1/59 A Safety Maturity Model was developed for use in UK coal mining operations in order to assess the level of compliance and effectiveness with a recently introduced standards based safety management system. The developed model allowed for a “self-assessment” of the maturity to be undertaken by teams from the individual sites. Assessments were undertaken at all sites (surface and underground) and in some cases within each site (e.g., underground operations, surface coal preparation plant). Once the level of maturity was established, improvement plans were developed to improve the maturity of individual standards that were weaker than the average and/or improve the maturity as a whole. The model was likened to a journey as there was a strong focus on continual improvement and effectiveness of the standards, rather than pure compliance. The model has been found to be a practical and useful tool by sites as a means of identifying strengths and weaknesses within their systems, and as a means of assurance with the safety management system standards. Minerals 2013-02-18 3 1 Article 10.3390/min3010059 59 72 2075-163X 2013-02-18 doi: 10.3390/min3010059 Patrick Foster Stuart Hoult http://www.mdpi.com/2075-163X/3/1/49 Biomining, the biotechnology that uses microorganisms to extract metals from ores and concentrates, is currently used exclusively for processing reduced ores and mine wastes. Metals of economic value also occur extensively in oxidized ores, such as nickel laterites. While these are not amenable to oxidative dissolution, the ferric iron minerals they contain can, in theory, be disrupted by iron reduction, causing associated metals to be released. We have harnessed the ability of the facultatively anaerobic, acidophilic bacterium Acidithiobacillus ferroooxidans to couple the oxidation of elemental sulphur to the reduction of ferric iron in the goethite fraction of a limonitic nickel ore at 30 °C. Nickel and other metals (Co, Cr and Mn) were effectively solubilised and maintained in solution due to the low pH (1.8) of the leach liquor. The results highlight the potential for the bioprocessing of oxidized, iron-rich ores using an approach that is energy-saving and environmentally-benign compared with metallurgical processes currently applied to the extraction of Ni from lateritic ores. Minerals 2013-01-30 3 1 Article 10.3390/min3010049 49 58 2075-163X 2013-01-30 doi: 10.3390/min3010049 D. Johnson Barry Grail Kevin Hallberg http://www.mdpi.com/2075-163X/3/1/36 Albitite-type uranium deposits are widely distributed, usually of low grade (<1% U3O8), but are often large and collectively contain over 1 million tonnes of U3O8. Uranium is hosted in a wide range of metamorphic lithologies, whose only common characteristic is that they have been extensively mylonitised. Ore minerals are disseminated and rarely in megascopic veins, within and adjacent to albitised mylonites. Grain size is uniformly fine, generally less than 50 microns. Scanning electron microscopy reveals that spatial association between uranium and various Ti-bearing phases is common. Gangue minerals include albite, carbonates (calcite and dolomite), and sodic pyroxene and amphibole. The ore rarely contains economic metals apart from uranium, phosphorous at Itataia being an exception. There is widespread evidence of hydrothermal zirconium mobility and hydrothermal zircon and other Zr phases are frequent and in some cases abundant gangue minerals. Positive correlations are noted between uranium and various high field strength elements. The group remains poorly described and understood, but a link to iron-oxide copper-gold (IOCG) deposits and/or carbonatite and/or alkaline magmatism is plausible. Minerals 2013-01-17 3 1 Review 10.3390/min3010036 36 48 2075-163X 2013-01-17 doi: 10.3390/min3010036 Andy Wilde http://www.mdpi.com/2075-163X/3/1/16 The purpose of this study was to evaluate health risks to operators of large and small load-haul-dump (LHD) vehicles exposed to whole-body vibration (WBV), based on criteria established in ISO 2631-1, ISO 2631-5, and EU Directive 2002/44 EC. Studies simultaneously evaluating health risks based on all three standards are limited. Operator WBV exposure was measured in accordance with ISO 2631-1 using a tri-axial seat pad accelerometer. According to ISO 2631-1, four of the seven large LHD vehicle operators and three of six small LHD vehicle operators were exposed to WBV above the 8-hour vibration dose value (VDV) health guidance caution zone (HGCZ). According to the EU Directive 2002/44/EC criteria one of the seven large LHD vehicle operators and one of the six small LHD vehicle operators were exposed to WBV above the VDV daily exposure limit. However, health risks predicted by ISO 2631-5 criteria only placed one of seven large LHD vehicle operators and one of the six small LHD vehicle operators in the high probability of an adverse health effect category. Thus, the probability of adverse health effects, associated with WBV exposure during LHD vehicle operation, is suggested to be greatest based on the ISO 2631-1 8-hour VDV HGCZ and lowest based on ISO 2631-5 Sed criterion values. Minerals 2013-01-14 3 1 Article 10.3390/min3010016 16 35 2075-163X 2013-01-14 doi: 10.3390/min3010016 Tammy Eger Aaron Kociolek James Dickey http://www.mdpi.com/2075-163X/3/1/1 It is more common than not, for mineral processing studies to proceed via the examination of model flotation systems with the resulting data often lacking statistical verification. The resultant concentrates and tails may then be subjected to a restricted range of analyses, for diagnosis of the flotation behavior variations observed, that themselves bias the outcomes. For instance surface analysis may be undertaken without reference to solution speciation, or liberation may be studied but surface speciation may not be taken into account. We propose an integrated approach whereby firstly the flotation data are vigorously scrutinized and the mineralogy, liberation, surface and solution speciation are examined in parallel to establish a chemical over view of the system. It is proposed that to make progress in the understanding of flotation systems, in terms of the minerals chemistry, that a multi-dimensional analytical approach is utilized and that the focus shifts towards the analysis of real ores and industrial flotation systems. Minerals 2013-01-08 3 1 Review 10.3390/min3010001 1 15 2075-163X 2013-01-08 doi: 10.3390/min3010001 Andrea Gerson Tim Napier-Munn http://www.mdpi.com/2075-163X/2/4/493 The feasibility of investigating the adsorption of n-octanohydroxamate collector on copper and iron oxide minerals with static secondary ion mass spectrometry has been assessed. Secondary ion mass spectra were determined for abraded surfaces of air-exposed copper metal, malachite, pseudomalachite and magnetite that had been conditioned in aqueous potassium hydrogen n-octanohydroxamate solution, as well as for the corresponding bulk CuII and FeIII complexes. In each case, the chemical species present at the solid/vacuum interface of a similarly prepared surface were established by X-ray photoelectron spectroscopy. The most abundant positive and negative metal-containing fragment ions identified for the bulk complexes were also found to be diagnostic secondary ions for the collector adsorbed on the oxide surfaces. The relative abundances of those diagnostic ions varied with, and could be rationalised by, the monolayer or multilayer coverage of the adsorbed collector. However, the precise mass values for the diagnostic ions were not able to corroborate the different bonding in the copper and iron hydroxamate systems that had been deduced from photoelectron and vibrational spectra. Parent secondary ions were able to provide supporting information on the co-adsorption of hydroxamic acid at each conditioned surface. Minerals 2012-12-10 2 4 Article 10.3390/min2040493 493 515 2075-163X 2012-12-10 doi: 10.3390/min2040493 Alan Buckley John Denman Gregory Hope http://www.mdpi.com/2075-163X/2/4/473 Column-leaching and pilot-scale experiments were conducted to evaluate the use of biosolids (sewage sludges) to control the mobilization of metals from contaminated soils with smelting slags. The pilot-scale experiments using amended soils showed that Cu, Pb and Sb were retained, decreasing their concentrations from 250 mg/L, 80 mg/L and 6 mg/L, respectively in the leachates of contaminated soils, to <20 mg/L, 40 mg/L and 4 mg/L, respectively, in the amended material. Hydrogeochemical modeling of the leachates using Minteq revealed that the degree of complexation of Cu rose 56.3% and 57.6% in leachates of amended soils. Moreover, Cu may be immobilized by biosolids, possibly via adsorption by oxyhydroxides of Fe or sorption by organic matter. The partial retention of Pb coincides with the possible precipitation of chloropyromorphite, which is the most stable mineral phase in the pH-Eh conditions of the leachates from the amended material. The retention of Sb may be associated with the precipitation of Sb2O3, which is the most stable mineral phase in the experimental conditions. The organic amendments used in this study increased some metal and metalloid concentrations in the leachates (Fe, Mn, Ni, As and Se), which suggests that the organic amendments could be used with caution to remediate metal contaminated areas. Minerals 2012-11-28 2 4 Article 10.3390/min2040473 473 492 2075-163X 2012-11-28 doi: 10.3390/min2040473 Andrés Navarro http://www.mdpi.com/2075-163X/2/4/459 The high solubility of copper sulphide minerals is an issue in the cyanidation of gold ores. The objective of this study was to quantify the effect of individual copper sulphide minerals on the Hunt process, which showed advantages over cyanidation. High purity djurleite, bornite and chalcopyrite, with a P70 of 70–74 microns, were mixed with fine quartz and gold powder (3–8 micron) to obtain a copper concentration of 0.3%. The ammonia-cyanide leaching of slurry with djurleite proved to be more effective than cyanidation; producing comparable extraction of gold (99%), while reducing the cyanide consumption from 5.8 to 1.2 kg/t NaCN. Lead nitrate improved the Hunt leaching. The lower cyanide consumption is associated to a significant reduction of copper dissolved. XPS surface analysis of djurleite showed that lead nitrate favored the formation of Cu(OH)2 species. Lead was also detected on the surface (oxide or hydroxide). Sulphide and copper compounds (cyanide and sulphide) were reaction products responsible for inhibiting the dissolution of gold. Lead nitrate added in the Hunt leaching of bornite produced 99% gold extraction. Surface reaction products were similar to djurleite. The cyanide consumption (~4.4 kg/t NaCN) was not reduced by the addition of ammonia. Cyanidation of chalcopyrite showed a lower consumption of cyanide 0.33 kg/t NaCN compared to 0.21 kg/t NaCN for Hunt. No significant interferences were observed in gold leaching with a slurry containing chalcopyrite. Minerals 2012-11-20 2 4 Article 10.3390/min2040459 459 472 2075-163X 2012-11-20 doi: 10.3390/min2040459 Guy Deschênes Hai Guo Chen Xia Allen Pratt Mike Fulton Yeonuk Choi Judith Price http://www.mdpi.com/2075-163X/2/4/435 In this paper we show that the pegmatite-forming processes responsible for the formation of the Malkhan pegmatites started at magmatic temperatures around 720 °C. The primary melts or supercritical fluids were very water- and boron-rich (maximum values of about 10% (g/g) B2O3) and over the temperature interval from 720 to 600 °C formed a pseudobinary solvus, indicated by the coexistence of two types of primary melt inclusions (type-A and type-B) representing a pair of conjugate melts. Due to the high water and boron concentration the pegmatite-forming melts are metastable and can be characterized either as genuine melts or silicate-rich fluids. This statement is underscored by Raman spectroscopic studies. This study suggested that the gel state proposed by some authors cannot represent the main stage of the pegmatite-forming processes in the Malkhan pegmatites, and probably in all others. However there are points in the evolution of the pegmatites where the gel- or gel-like state has left traces in form of real gel inclusions in some mineral in the Malkhan pegmatite, however only in a late, fluid dominated stage. Minerals 2012-11-15 2 4 Article 10.3390/min2040435 435 458 2075-163X 2012-11-15 doi: 10.3390/min2040435 Rainer Thomas Paul Davidson Elena Badanina http://www.mdpi.com/2075-163X/2/4/426 Indium is a typical chalcophile element of the Earth’s crust, with a very low average content that seldom forms specific minerals, occurring mainly as dispersed in polymetallic sulphides. Indium recovery is based primarily on zinc extraction from sphalerite, the prototype of so-called tetrahedral sulphides, wherein metal ions fill half of the available tetrahedral sites within the cubic closest packing of sulphur anions, leaving interstices accessible for further in-filling. Ascertaining the tendency towards the establishment of In-In interactions through an x-ray absorption spectroscopy approach would efficiently contribute to understanding the behavior of indium in the carrier mineral. The successful results of applying such a near-edge absorption (XANES) study at In L3-edge to samples collected at the Lagoa Salgada polymetallic orebody in the Iberian Pyrite Belt (IPB) are described and the crystal chemistry of indium is re-evaluated, disclosing a potential clue for the metal binding state in polymetallic sulphides. Minerals 2012-11-06 2 4 Article 10.3390/min2040426 426 434 2075-163X 2012-11-06 doi: 10.3390/min2040426 Maria-Ondina Figueiredo Teresa Pereira da Silva Daniel de Oliveira Diogo Rosa http://www.mdpi.com/2075-163X/2/4/417 Mining is currently experiencing a rapid growth in the development and uptake of automation and other new technologies (such as collision detection systems); however, they are often developed from a technology-centred perspective that does not explicitly consider the end-user. This paper first presents a review of the technologies currently available (or near-market) and the likely human factors issues associated with them. The second part of the paper presents a potential long term strategy for research and development that aims to maximise the safety and health benefits for operators of such new technologies. The strategy includes a four stage research and development process, this covers: better understanding the needs for technology, user requirements and risk/cost analysis; human element design, procurement and deployment processes; evaluation and verification of the strategy; and dissemination of it to relevant stakeholders (including equipment manufacturers, mine site purchasers and regulators). The paper concludes by stressing the importance of considering the human element with respect to new mining technologies and the likely benefits of adopting the type of strategy proposed here. The overall vision is for mining to become safer and healthier through effective user-centred design and deployment of new technologies that serve both operator needs and the demands of the workplace. Minerals 2012-10-31 2 4 Review 10.3390/min2040417 417 425 2075-163X 2012-10-31 doi: 10.3390/min2040417 Tim Horberry http://www.mdpi.com/2075-163X/2/4/385 The Early Proterozoic (~1.9 Ga) Skellefte mining district in northern Sweden hosts abundant base metal deposits, but there are also gold-only deposits. The Åkerberg gold ore is unusual given the noted lack of alteration, a scarcity of sulfides and gold associated with thin (mm-cm wide) parallel quartz veins hosted in a gabbro. The gold content is positively correlated with the density of quartz veins, but gold often occurs between veins and also in parts of the gabbro where there is no veining. The gabbro is intruded by a granodiorite and associated pegmatite bodies, and U-Pb dating of zircon and baddeleyite suggest that these lithologies developed close in time at around 1.88 Ga ago. There are no primary inclusions in quartz veins, but different types of secondary aqueous inclusions occur. The Åkerberg ore is interpreted as a sheeted vein complex, with veins constrained to tensional cracks induced when a granodioritic magma intruded the competent, sheet-like gabbro intrusion. It is suggested that unmixing of the felsic magma also produced pegmatite bodies and a gel-like melt which invaded fractures in the gabbro and deposited silica. In a comparison, the Åkerberg ore shares many characteristics with the intrusion-related style of gold mineralizations. Minerals 2012-10-31 2 4 Article 10.3390/min2040385 385 416 2075-163X 2012-10-31 doi: 10.3390/min2040385 Kjell Billström Benny Mattson Ulf Söderlund Hans Årebäck Curt Broman http://www.mdpi.com/2075-163X/2/4/365 A variety of platinum-group-minerals (PGM) have been found to occur associated with the chromitite and dunite layers in the Niquelândia igneous complex. Two genetically distinct populations of PGM have been identified corresponding to phases crystallized at high temperatures (primary), and others formed or modified during post-magmatic serpentinization and lateritic weathering (secondary). Primary PGM have been found in moderately serpentinized chromitite and dunite, usually included in fresh chromite grains or partially oxidized interstitial sulfides. Due to topographically controlled lateritic weathering, the silicate rocks are totally transformed to a smectite-kaolinite-garnierite-amorphous silica assemblage, while the chromite is changed into a massive aggregate of a spinel phase having low-Mg and a low Fe3+/Fe2+ ratio, intimately associated with Ti-minerals, amorphous Fe-hydroxides, goethite, hematite and magnetite. The PGM in part survive alteration, and in part are corroded as a result of deep chemical weathering. Laurite is altered to Ru-oxides or re-crystallizes together with secondary Mg-ilmenite. Other PGM, especially the Pt-Fe alloys, re-precipitate within the altered chromite together with kaolinite and Fe-hydroxides. Textural evidence suggests that re-deposition of secondary PGM took place during chromite alteration, controlled by variation of the redox conditions on a microscopic scale. Minerals 2012-10-30 2 4 Article 10.3390/min2040365 365 384 2075-163X 2012-10-30 doi: 10.3390/min2040365 Giorgio Garuti Federica Zaccarini Joaquin Proenza Oskar Thalhammer Nelson Angeli http://www.mdpi.com/2075-163X/2/4/338 Microbial carbonate mineralization is widespread in nature and among microorganisms, and of vast ecological and geological importance. However, our understanding of the mechanisms that trigger and control processes such as calcification, i.e., mineralization of CO2 to calcium carbonate (CaCO3), is limited and literature on cyanobacterial calcification is oftentimes bewildering and occasionally controversial. In cyanobacteria, calcification may be intimately associated with the carbon dioxide-(CO2) concentrating mechanism (CCM), a biochemical system that allows the cells to raise the concentration of CO2 at the site of the carboxylating enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) up to 1000-fold over that in the surrounding medium. A comprehensive understanding of biologically induced carbonate mineralization is important for our ability to assess its role in past, present, and future carbon cycling, interpret paleontological data, and for evaluating the process as a means for biological carbon capture and storage (CCS). In this review we summarize and discuss the metabolic, physiological and structural features of cyanobacteria that may be involved in the reactions leading to mineral formation and precipitation, present a conceptual model of cyanobacterial calcification, and, finally, suggest practical applications for cyanobacterial carbonate mineralization. Minerals 2012-10-29 2 4 Review 10.3390/min2040338 338 364 2075-163X 2012-10-29 doi: 10.3390/min2040338 Nina Kamennaya Caroline Ajo-Franklin Trent Northen Christer Jansson http://www.mdpi.com/2075-163X/2/4/318 In this study, we compare the major- and trace-element compositions of olivine, garnet, and clinopyroxene that occur as single crystals (142 grains), with those derived from xenoliths (51 samples) from six kimberlites in the Lucapa area, northeastern Angola: Tchiuzo, Anomaly 116, Catoca, Alto Cuilo-4, Alto Cuilo-63 and Cucumbi-79. The samples were analyzed using electron probe microanalysis (EPMA) and laser-ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS). The results suggest different paragenetic associations for these kimberlites in the Lucapa area. Compositional overlap in some of the macrocryst and mantle xenolith samples indicates a xenocrystic origin for some of those macrocrysts. The presence of mantle xenocrysts suggests the possibility of finding diamond. Geothermobarometric calculations were carried out using EPMA data from xenoliths by applying the program PTEXL.XLT. Additional well calibrated single-clinopyroxene thermobarometric calculations were also applied. Results indicate the underlying mantle experienced different equilibration conditions. Subsequent metasomatic enrichment events also support a hypothesis of different sources for the kimberlites. These findings contribute to a better understanding of the petrogenetic evolution of the kimberlites in northeastern Angola and have important implications for diamond exploration. Minerals 2012-10-26 2 4 Article 10.3390/min2040318 318 337 2075-163X 2012-10-26 doi: 10.3390/min2040318 Sandra Robles-Cruz Joan Melgarejo Salvador Galí Monica Escayola http://www.mdpi.com/2075-163X/2/4/300 The European Union (EU) is highly dependent on critical and rare metals which are very important for a sustainable development. However, European industry is not able to cover its demands from native sources and it imports commodities from third countries. Greece is one of the EU countries with the most potential for supplying these strategic metallic raw materials in the future, since it hosts a large number of ore deposits. The epithermal- and porphyry-type deposits and the reduced intrusion related systems of the Serbomacedonian and the Rhodope metallogenic provinces in Northeastern Greece are promising targets for a future exploitation and exploration in Sb, Te, Mo, Re, Ga, In, REE and PGE. Greece is the leading producer of Ni and Al in the EU from laterites and bauxites of central and northern Greece. These deposits also contain significant amounts of Co or REE which should be considered in the future plans of the processing industries. REE are found in high contents at the placer deposits between Chalkidiki and Kavala (North Greece) and elevated PGE concentrations are associated with the chromitites of northwestern Greece. Therefore, the mineral wealth of Greece can contribute significantly to a sustainable and a competitive economy of Europe. Minerals 2012-10-19 2 4 Review 10.3390/min2040300 300 317 2075-163X 2012-10-19 doi: 10.3390/min2040300 Vasilios Melfos Panagiotis Ch. Voudouris http://www.mdpi.com/2075-163X/2/4/283 Effective flocculation and dewatering of mineral processing streams containing clays are microstructure dependent in clay-water systems. Initial clay flocculation is crucial in the design and for the development of a new methodology of gas exploitation. Microstructural engineering of clay aggregates using covalent cations and Keggin macromolecules have been monitored using the new state of the art Transmission X-ray Microscope (TXM) with 60 nm tomography resolution installed in a Taiwanese synchrotron. The 3-D reconstructions from TXM images show complex aggregation structures in montmorillonite aqueous suspensions after treatment with Na+, Ca2+ and Al13 Keggin macromolecules. Na-montmorillonite displays elongated, parallel, well-orientated and closed-void cellular networks, 0.5–3 µm in diameter. After treatment by covalent cations, the coagulated structure displays much smaller, randomly orientated and openly connected cells, 300–600 nm in diameter. The average distances measured between montmorillonite sheets was around 450 nm, which is less than half of the cell dimension measured in Na-montmorillonite. The most dramatic structural changes were observed after treatment by Al13 Keggin; aggregates then became arranged in compacted domains of a 300 nm average diameter composed of thick face-to-face oriented sheets, which forms porous aggregates with larger intra-aggregate open and connected voids. Minerals 2012-10-18 2 4 Article 10.3390/min2040283 283 299 2075-163X 2012-10-18 doi: 10.3390/min2040283 Marek S. Żbik Yen-Fang Song Ray L. Frost Chun-Chieh Wang http://www.mdpi.com/2075-163X/2/4/272 Fifteen multi-national mining companies are currently members of the Earth Moving Equipment Safety Round Table (EMESRT). Formed in 2006, EMESRT engages with mining equipment manufacturers with the aim of accelerating improvements in the safe design of mining equipment. An initial stage in this process was to communicate industry understanding of the risks in the form of “design philosophies” that describe potential unwanted events in eight hazard categories. A technique for analysing risks associated with operation and maintenance tasks, the Operability and Maintainability Analysis Technique (OMAT), was subsequently developed and trialed. The next step is the EMESRT Design Evaluation for Equipment Procurement (EDEEP) process. The aims of requesting manufacturers to follow this process are to provide equipment purchasers with a common way of assessing how well the issues in the EMESRT Design Philosophies are addressed in the equipment design; and to provide manufacturers with additional information for use during equipment design. The process involves identifying priority tasks based on frequency and severity of the consequences of potential unwanted events identified in the EMESRT Design Philosophies; undertaking a task-based risk assessment of priority tasks in conjunction with site-based personnel; evaluating the effectiveness of control measures; and providing information about safe design features in a standardised format. Minerals 2012-10-15 2 4 Article 10.3390/min2040272 272 282 2075-163X 2012-10-15 doi: 10.3390/min2040272 Robin Burgess-Limerick Jim Joy Tristan Cooke Tim Horberry http://www.mdpi.com/2075-163X/2/4/258 A flotation bank is a serial arrangement of cells. How to optimally operate a bank remains a challenge. This article reviews three reported strategies: air profiling, mass-pull (froth velocity) profiling and Peak Air Recovery (PAR) profiling. These are all ways of manipulating the recovery profile down a bank, which may be the property being exploited. Mathematical analysis has shown that a flat cell-by-cell recovery profile maximizes the separation of two floatable minerals for a given target bank recovery when the relative floatability is constant down the bank. Available bank survey data are analyzed with respect to recovery profiling. Possible variations on recovery profile to minimize entrainment are discussed. Minerals 2012-10-10 2 4 Article 10.3390/min2040258 258 271 2075-163X 2012-10-10 doi: 10.3390/min2040258 Miguel Maldonado Rodrigo Araya James Finch http://www.mdpi.com/2075-163X/2/3/244 The review presents synthetic approaches to modern rhenium-based catalysts. Creation of an active center is considered as a process of obtaining a nanoparticle or a molecule, immobilized within a matrix of the substrate. Selective chemical routes to preparation of particles of rhenium alloys, rhenium oxides and the molecules of alkyltrioxorhenium, and their insertion into porous structure of zeolites, ordered mesoporous MCM matrices, anodic mesoporous alumina, and porous transition metal oxides are considered. Structure-property relationships are traced for these catalysts in relation to such processes as alkylation and isomerization, olefin metathesis, selective oxidation of olefins, methanol to formaldehyde conversion, etc. Minerals 2012-08-14 2 3 Review 10.3390/min2030244 244 257 2075-163X 2012-08-14 doi: 10.3390/min2030244 Vadim G. Kessler Gulaim A. Seisenbaeva http://www.mdpi.com/2075-163X/2/3/228 Tertiary low sulfidation (LS) epithermal deposits in the western USA often show evidence of the former presence of nanoparticle-sized precious-metal and silica phases in the highest grade (bonanza) ores. Here, nanoparticles are defined to have a size less than ~10−7 m. The ore-mineral textures that formed from aggregation of nanoparticles (or colloids) observed to date in these ores include electrum and naumannite (Ag2Se). Here it is proposed that chalcopyrite also forms nanoparticles in these ores, but sulfide nanoparticles apparently have significantly different physical (surface) properties than the precious-metal phases, and thus exhibit different mineral textures (e.g., no textural evidence of previous chalcopyrite nanoparticles). Textures described here show that nanoparticles of precious-metal phases and silica were episodically and often repeatedly deposited to form the banded bonanza veins typical of many western USA epithermal deposits. Chalcopyrite is the most abundant metal-sulfide mineral in these bonanza ores, and it was also deposited episodically as well, and it appears to replace earlier formed naumannite dendrites. However, this apparent “replacement” texture may just be the result of naumannite dendrite limbs trapping chalcopyrite nanoparticles that later recrystallized to the apparent replacement texture. The episodic and repetitive nature of the metal-depositing events may record periodic “degassing” of magma chambers at depth, where metals are repeatedly delivered to the shallow epithermal environment by “vapor-phase” metal (loid) transport. Minerals 2012-08-14 2 3 Review 10.3390/min2030228 228 243 2075-163X 2012-08-14 doi: 10.3390/min2030228 James A. Saunders http://www.mdpi.com/2075-163X/2/3/208 Frothers are surfactants commonly used to reduce bubble size in mineral flotation. This paper describes a methodology to characterize frothers by relating impact on bubble size reduction represented by CCC (critical coalescence concentration) to frother structure represented by HLB (hydrophile-lipophile balance). Thirty-six surfactants were tested from three frother families: Aliphatic Alcohols, Polypropylene Glycol Alkyl Ethers and Polypropylene Glycols, covering a range in alkyl groups (represented by n, the number of carbon atoms) and number of Propylene Oxide groups (represented by m). The Sauter mean size (D32) was derived from bubble size distribution measured in a 0.8 m3 mechanical flotation cell. The D32 vs. concentration data were fitted to a 3-parameter model to determine CCC95, the concentration giving 95% reduction in bubble size compared to water only. It was shown that each family exhibits a unique CCC95-HLB relationship dependent on n and m. Empirical models were developed to predict CCC95 either from HLB or directly from n and m. Commercial frothers of known family were shown to fit the relationships. Use of the model to predict D32 is illustrated. Minerals 2012-08-13 2 3 Article 10.3390/min2030208 208 227 2075-163X 2012-08-13 doi: 10.3390/min2030208 Wei Zhang Jan E. Nesset Ramachandra Rao James A. Finch http://www.mdpi.com/2075-163X/2/3/169 The epigenetic Zn-Pb deposits in the Lycksele-Storuman ore district, northern Sweden, are hosted by Paleoproterozoic basement near the margin of the Caledonian mountains. A paleogeographic reconstruction suggests that platform sediments, including Cambrian shales, overlaid the mineralised basement. The mineralisation type, containing sphalerite, galena, calcite and fluorite, is confined to veins and breccias and interpreted to be of Mississippi Valley Type (MVT) style. There is no appreciable wall rock alteration. Fluid inclusion work reveals coexisting aqueous and hydrocarbon fluids. Ore deposition is interpreted to have occurred during mixing of two fluids; a cool ( Minerals 2012-06-29 2 3 Article 10.3390/min2030169 169 207 2075-163X 2012-06-29 doi: 10.3390/min2030169 Kjell Billström Curt Broman Jens Schneider Warren Pratt Göran Skogsmo http://www.mdpi.com/2075-163X/2/2/129 This paper draws on research conducted in the past two decades examining issues related to the human element in mine disasters. While much of the emergency response community employs a systems approach that takes into account psychosocial issues as they impact all aspects of an emergency, the mining industry has lagged behind in integrating this critical element. It is only within the past few years that behavioral interventions have begun to be seen as a part of disaster readiness and resiliency in the industry. The authors discuss the potential applications of psychosocial studies and suggest ways to improve mine emergency planning, psychological support, and decision-making during a response, as well as actions in the aftermath of incidents. Topics covered, among others, include an economic rationale for including such studies in planning a mine emergency response, sociological issues as they impact such things as leadership and rescue team dynamics, and psychological issues that have an effect on individual capacity to function under stress such as during escape, in refuge alternatives, and in body recovery. This information is intended to influence the mine emergency escape curriculum and impact actions and decision-making during and after a mine emergency. The ultimate goal is to mitigate the trauma experienced by individuals, the organization, and the community. Minerals 2012-06-11 2 2 Article 10.3390/min2020129 129 168 2075-163X 2012-06-11 doi: 10.3390/min2020129 Kathleen M. Kowalski-Trakofler Charles Vaught http://www.mdpi.com/2075-163X/2/2/118 Although some strains of Leptothrix spp. isolated from aquatic environments have been characterized by culturing them in laboratory conditions, they often show morphological and chemical features distinct from those found in natural environments. To resolve this discrepancy, a novel cultivation method was devised for culturing such strains in natural groundwater. Leptothrix sp. strain OUMS1 was pre-cultured in a medium lacking Fe for 2 days, and then injected into a small dialysis tube bag and immersed in a container with continuously flowing groundwater for 1–3 and 14 days. Microscopic analysis of the initial phase of sheath formation and arbitrary comparisons with medium cultures revealed that in groundwater the surface coat of the sheath comprised much thinner fibrils, and an inner sheath wall that was much thinner and more indistinct compared with medium cultures. These differences were probably attributable to poorer secretion from the cell surface in groundwater conditions. A nutrient-rich medium likely activates cell metabolism and promotes secretion, resulting in a thicker inner sheath wall and thicker outer coat fibrils. Aqueous-phase Fe was deposited on immature sheaths in a similar manner in both cultures. These results indicate that laboratory culture of isolated microbes does not always reflect their characteristics in natural environments. Minerals 2012-05-23 2 2 Article 10.3390/min2020118 118 128 2075-163X 2012-05-23 doi: 10.3390/min2020118 Tomoko Suzuki Hiromichi Ishihara Mitsuaki Furutani Tomonori Shiraishi Hitoshi Kunoh Jun Takada http://www.mdpi.com/2075-163X/2/2/100 The recent definitive deuterium solid state NMR spectroscopic evidence for structural water in fluor- and hydroxylapatites has prompted our study of the conditions necessary for the removal and reincorporation of this important structural feature of apatites. Thermal gravimetric analysis of 20 synthetic carbonated calcium hydroxylapatite (CCaApOH) samples and nine carbonated calcium fluorapatite (CCaApF) samples has been used to determine the amount of structural and adsorbed water in each sample. No correlation between the weight percent and number of moles of structural water and the weight percent carbonate in CCaApOH and CCaApF has been found. In contrast, there appears to be a relationship between the amount of adsorbed water and the carbonate concentration in the fluorapatites prepared with a two hour digestion time, as well as in the hydroxylapatites prepared with one hour digestion periods, presumably due to the effect of carbonate on crystallite size. Structural water can be removed from the apatite lattice, primarily above 200 °C, but heating to over 550 °C is required for complete removal. This water can be partly reincorporated through an apparently kinetically-controlled process that is enhanced by an increase in time and/or temperature. We speculate that the incorporation of structural water occurs at the beginning of the formation of the apatite structure, approximately coincident with the incorporation of carbonate. We also speculate that water is both removed and reincorporated by proton transfers from water molecules to hydroxide ions. Minerals 2012-03-30 2 2 Article 10.3390/min2020100 100 117 2075-163X 2012-03-30 doi: 10.3390/min2020100 Claude Yoder Jill Pasteris Kimberly Worcester Demetra Schermerhorn Mitchell Sternlieb Jennifer Goldenberg Zachary Wilt http://www.mdpi.com/2075-163X/2/2/85 Nerita undata is a marine gastropod, the shell of which consists of an external layer composed of very fine, long and undulating calcite prisms, and of an internal aragonite crossed-lamellar layer. As for any Ca-carbonate shell, both layers are composite materials, resulting from the sub-micrometric association of organic macromolecules with the mineral phase. But at the transition between the two layers, in situ synchrotron-based mapping using μ-XANES spectroscopy performed at the S K-edge and SR-FTIR spectroscopy reveals that biochemical compositions change correlatively with the mineral phase, such as displayed by the distribution of sulfur-containing organic compounds (S-polysaccharides or S-amino acids) and organic molecular groups (amide I and II bands). These results highlight the complex change of secretory activity operated by the mineralizing tissue (the mollusk mantle) between these two parts of the shell, which is suspected to minutely control the setting-up of the crossed-lamellar microstructural pattern over the calcite prisms—A not so straightforward feature. Minerals 2012-03-29 2 2 Article 10.3390/min2020085 85 99 2075-163X 2012-03-29 doi: 10.3390/min2020085 Julius Nouet Marine Cotte Jean-Pierre Cuif Yannicke Dauphin Murielle Salomé http://www.mdpi.com/2075-163X/2/1/65 This paper critically assesses if accessible lithium resources are sufficient for expanded demand due to lithium battery electric vehicles. The ultimately recoverable resources (URR) of lithium globally were estimated at between 19.3 (Case 1) and 55.0 (Case 3) Mt Li; Best Estimate (BE) was 23.6 Mt Li. The Mohr 2010 model was modified to project lithium supply. The Case 1 URR scenario indicates sufficient lithium for a 77% maximum penetration of lithium battery electric vehicles in 2080 whereas supply is adequate to beyond 2200 in the Case 3 URR scenario. Global lithium demand approached a maximum of 857 kt Li/y, with a 100% penetration of lithium vehicles, 3.5 people per car and 10 billion population. Minerals 2012-03-19 2 1 Article 10.3390/min2010065 65 84 2075-163X 2012-03-19 doi: 10.3390/min2010065 Steve H. Mohr GavinM. Mudd Damien Giurco http://www.mdpi.com/2075-163X/2/1/55 Nacre, or mother of pearl, is composed of aragonite tablets and is produced by some mollusks. Because of the highly organized internal structure, chemical complexity, mechanical properties and optical effects of nacre, its formation is among the best-studied examples of calcium carbonate biomineralization. The pearl oyster Pinctada margaritifera is harvested in French Polynesia for pearl farming. The quality of the pearl depends on the quality of the nacre on its surface and its iridescent colors are affected by the thickness of the layers. Here we report on an experimental study conducted to influence the shape and the thickness of nacre tablets by keeping pearl oysters at four different depths (7, 20, 30 and 39 m) for one week. Scanning electron microscopy was used to measure the thickness of the nacre tablets and to analyze their final shape. The shape of the tablets changed from hexagonal to rhomboid at a depth of 39 m. The change in shape led to a change in size. The thickness of the tablets was reduced by between 16 and 30% on average. We also measured the oxygen isotopic composition using Secondary Ion Mass Spectrometry. In this study, we demonstrated that depth can modify the size, shape and thickness of nacre tablets, but not the d18O. This environmental modification is important for the biomineralization of the shell of the pearl oyster Pinctada margaritifera. Minerals 2012-03-19 2 1 Article 10.3390/min2010055 55 64 2075-163X 2012-03-19 doi: 10.3390/min2010055 Marthe Rousseau Claire Rollion-Bard http://www.mdpi.com/2075-163X/2/1/40 Mollusk shells, especially the nacre, are of commercial interest as well as palaeoenvironmental proxies. They are also investigated as biomaterials for medical purposes and biomimetics. Although the mineralogy is well-known and unique (aragonite tablets), the organic components are various. However, determination of the precise composition of the soluble organic matrix (SOM) of the nacreous layer is difficult. Among the range of possible techniques, 1D electrophoresis and High-performance liquid chromatography (HPLC) have previously been applied separately to differentiate pI and molecular weights. To date, no clear correlation has been established between the two parameters obtained in such conditions. Here, we report the use of preparative electrophoresis, coupled with HPLC, to determine the molecular weights of the pI fractions. The results are compared with 2D gel electrophoresis. It is shown that both methods have drawbacks and advantages, and are not redundant. The complexity of the composition of the nacreous tablet shown by scanning electron microscope (SEM) and Atomic Force Microscope (AFM) observations is also evidenced by electrophoresis and HPLC. Minerals 2012-02-27 2 1 Article 10.3390/min2010040 40 54 2075-163X 2012-02-27 doi: 10.3390/min2010040 Yannicke Dauphin Julius Nouet http://www.mdpi.com/2075-163X/2/1/11 In several recent models of invertebrate skeletogenesis, Ca-carbonate crystallization occurs within a liquid-filled chamber. No explanation is given neither for the simultaneous occurrence of distinct polymorphs of Ca-carbonate within these liquid volumes, nor for the spatial arrangement of the mineral units which are always organized in species-specific structural sequences. Results of a series of physical characterizations applied to reference skeletal materials reveal the inadequacy of this liquid-filled chamber model to account for structural and chemical properties of the shell building units. Simultaneously, these data provide convergent pieces of evidence for a specific mode of crystallization developed throughout various invertebrate phyla, supporting the hypothesized “common strategy” based on a multi-scaled control exerted on formation of their calcareous hard parts. Minerals 2012-02-27 2 1 Review 10.3390/min2010011 11 39 2075-163X 2012-02-27 doi: 10.3390/min2010011 Jean-Pierre Cuif Yannicke Dauphin Gernot Nehrke Julius Nouet Alberto Perez-Huerta http://www.mdpi.com/2075-163X/2/1/1 Oxidation of iron sulfides in waste rock dumps and tailings deposits may result in formation of acid rock drainage (ARD), which often is a challenging problem at mine sites. Therefore, integrating an ARD management plan into the actual mine operations in the early phases of exploration, continuing through the mine life until final closure might be successful and decrease the environmental impact. A thorough characterization of ore and waste should be performed at an early stage. A detailed knowledge of mineralogical composition, chemical composition and physical properties such as grain size, porosity and hydraulic conductivity of the different waste types is necessary for reliable predictions of ARD formation and efficiency of mitigation measures. Different approaches to prevent and mitigate ARD are discussed. Another key element of successfully planning to prevent ARD and to close a mining operation sustainably is to engage the mine stakeholders (regulators, community and government leaders, non-governmental organization (NGOs) and lenders) in helping develop and implement the ARD management plan. Minerals 2012-02-08 2 1 Review 10.3390/min2010001 1 10 2075-163X 2012-02-08 doi: 10.3390/min2010001 Björn Öhlander Terrence Chatwin Lena Alakangas http://www.mdpi.com/2075-163X/1/1/157 In an aquatic environment, the genus Leptothrix produces an extracellular Fe- or Mn-encrusted tubular sheath composed of a complex hybrid of bacterial exopolymers and aqueous-phase inorganic elements. This ultrastructural study investigated initial assemblage of bacterial saccharic fibrils and subsequent deposition of aqueous-phase inorganic elements to form the immature sheath skeleton of cultured Leptothrix sp. strain OUMS1. After one day of culture, a globular and/or thread-like secretion was observed on the surface of the bacterial cell envelope, and secreted bodies were transported across the intervening space away from the cell to form an immature sheath skeleton comprising assembled and intermingled fibrils. Energy dispersive X-ray microanalysis and specific Bi-staining detected a distinguishable level of P, trace Si, and a notable amount of carbohydrates in the skeleton, but not Fe. By the second day, the skeleton was prominently thickened with an inner layer of almost parallel aligned fibrils, along with low level of Fe deposition, whereas an outer intermingled fibrous layer exhibited heavy deposition of Fe along with significant deposition of P and Si. These results indicate that basic sheath-construction proceeds in two steps under culture conditions: an initial assemblage of bacterial saccharic fibrils originated from the cell envelope and the subsequent deposition of aqueous-phase Fe, P, and Si. Minerals 2011-12-14 1 1 Article 10.3390/min1010157 157 166 2075-163X 2011-12-14 doi: 10.3390/min1010157 Mitsuaki Furutani Tomoko Suzuki Hiromichi Ishihara Hideki Hashimoto Hitoshi Kunoh Jun Takada http://www.mdpi.com/2075-163X/1/1/144 The bulk minerals iron ore and bauxite cause significant greenhouse emissions in their processing to steel and aluminum respectively. The level of these emissions is highly dependent on the source of electrical and thermal energy. However, they also cause significant greenhouse gas emissions from their transportation across the globe for processing. This study examines these minerals from the perspective of greenhouse gas avoidance, examining the location of processing as an option for reducing transportation-based and process-based emissions. The analysis proposes a “radius of reduction” to define the potential for transporting ore to reduce emissions by offshore processing. Overall scenarios for localized steel production indicate potential for 85% reduction of transport emissions in the steel industry and 14% of overall industry emissions. Local high-carbon electricity grids and inefficient production mean that the benefit of reduced transportation is partially counteracted by increased processing emissions. The transportation of all global bauxite to Norway and other nations with low-emissions electricity for production of aluminum could result in an overall reduction of industry emissions of up to 44%. Minerals 2011-12-12 1 1 Article 10.3390/min1010144 144 156 2075-163X 2011-12-12 doi: 10.3390/min1010144 Benjamin C. McLellan http://www.mdpi.com/2075-163X/1/1/122 Objectives: In artisanal small-scale gold mining (ASGM) areas in many developing countries, mercury (Hg) is used to extract gold from ore. Data of 1250 participants from Indonesia, Mongolia, Philippines, Tanzania, and Zimbabwe were combined to analyze the relation between exposure in ASGM areas and body burden. Methods: Four groups were selected relating to their intensity of contact with mercury: (i) a non-exposed control group; (ii) a low exposed group with participants only living in mining areas, but not working as miners; (iii) a medium exposed group, miners living in exposed areas and working with mercury without smelting amalgam; and (iv) a high exposed group, miners living in exposed areas and smelting amalgam. Results: Compared to the non-exposed control group, participants living and/ or miners working in highly exposed areas have significantly higher concentration of total mercury in urine, hair and blood (p-value < 0.001). The median mercury value in urine in the control group is < 0.2 µg/L. In the high exposed group of amalgam smelters, the median in urine is 12.0 µg/L. The median in blood in the control group is < 0.93 µg/L. The median level in blood of the high exposed group is 7.56 µg/L. The median for mercury in hair samples from the control group is 0.21 µg/g. In the high exposed group the median hair concentration is 2.4 µg/g hair. Mercury levels also differ considerably between the countries, reflecting a diverse background burden due to different fish eating habits and different work place methods. Conclusions: A high percentage of exposed individuals had levels above threshold values. These high levels of mercury are likely to be related with serious health problems. Minerals 2011-11-30 1 1 Article 10.3390/min1010122 122 143 2075-163X 2011-11-30 doi: 10.3390/min1010122 Jennifer Baeuml Stephan Bose-O’Reilly Raffaella Matteucci Gothe Beate Lettmeier Gabriele Roider Gustav Drasch Uwe Siebert http://www.mdpi.com/2075-163X/1/1/109 Same level falls continue to contribute to an alarming number of slip/trip/fall injuries in the mining workforce. The objective of this study was to investigate how walking on different surface types and transverse slopes influences gait parameters that may be associated with a trip event. Gait analysis was performed for ten subjects on two orientations (level and sloped) on smooth, hard surface (control) and irregular (gravel, larger rocks) surfaces. Walking on irregular surfaces significantly increased toe clearance compared to walking on the smooth surface. There was a significant (p < 0.05) decrease in cadence (steps/min), stride length (m), and speed (m/s) from control to gravel to larger rocks. Significant changes in external rotation and increased knee flexion while walking on irregular surfaces were observed. Toe and heel clearance requirements increased on irregular surfaces, which may provide an explanation for trip-induced falls; however, the gait alterations observed in the experienced workers used as subjects would likely improve stability and recovery from a trip. Minerals 2011-11-23 1 1 Article 10.3390/min1010109 109 121 2075-163X 2011-11-23 doi: 10.3390/min1010109 Andrew Merryweather Byungju Yoo Donald Bloswick http://www.mdpi.com/2075-163X/1/1/73 The characterization, evaluation and remediation of polluted soils is one of the present environmental challenges to be addressed in the coming years. The origin of trace elements in soils can be either geogenic or anthropogenic, but only the latter is interesting from a legal point of view. The hazard of the pollutants in the soils not only depends on their total concentration, but particularly on their availability. The mobility of the trace elements depends on their speciation, and it is also affected by several soil parameters. Mining activity is one of the most important anthropogenic causes of soil pollution. As a case study, this work is focused in the Riotinto mining area (Iberian Pyrite Belt, IPB, SW Spain). The IPB is one of the most important metallogenic provinces in the world and it has been exploited for thousands of years. The disposal of mining residues has produced important sources of contamination by trace elements and acidic waters affecting soils and rivers. In addition to these problems, the closure of mines in the Pyrite Belt at the end of the 20th Century has led to a great loss of employment, which has caused the development of an intensive agriculture of citrus fruits as a new source of income. The intensive growing of citrus fruits and the traditional subsistence agriculture have been developed surrounding the mining areas and on floodplains near to mining sites. The level of soil pollution has not been taken into account in these cases, nor has its impact on the health of the inhabitants of these areas. Therefore, it is of great interest to study the current state of the cultivated soils and the sources and types of contaminants derived from mining activity in order to program its decontamination, where appropriate, according to legislation. In order to know the present and future hazard posed by the soils chemical and mineralogical speciation has been carried out, given that the availability of a metal depends on the phase in which it is found. The results showed that mining activity has caused high levels of As, Cu, Pb and Zn in several cultivated soils. Moreover, Cu, Pb and Zn showed a high bioavailability. This suggests that at least other studies are necessary to preserve health in the inhabitants of this area. The methodology carried out in this work allowed to select potentially polluted areas where agricultural activities are not recommended. Minerals 2011-11-07 1 1 Article 10.3390/min1010073 73 108 2075-163X 2011-11-07 doi: 10.3390/min1010073 Isabel González Emilio Galán Antonio Romero http://www.mdpi.com/2075-163X/1/1/49 This review describes some of the literature pertaining to sleep deprivation, shift working, and heat exposure. Consequences of each on human cognitive function, particularly with respect to vigilance and attentional capacity are reviewed. Individually, each of these factors is known to impair human cognition; however, we propose the possibility that for miners working in hot underground environments and who are assigned to rotating shifts, the combination may leave miners with significant degrees of fatigue and decreased ability to focus on tasks. We suggest that such decreased capacity for vigilance is a source of concern in an occupational health and safety context. Minerals 2011-11-02 1 1 Review 10.3390/min1010049 49 72 2075-163X 2011-11-02 doi: 10.3390/min1010049 Glenn Legault http://www.mdpi.com/2075-163X/1/1/30 The purpose of this study was to investigate the relationship between community-level exposure to changes in economic conditions and the incidence and prevalence of mental disorders and cardiovascular disease in 29 resource-based communities (with a focus on mining communities) in British Columbia (BC) during a period of time marked by an economic downturn (1991–2002) The investigation relied on Labour Force Survey (LFS) and Statistics Canada Census data, and health records from the British Columbia Ministry of Health (MoH). Age and sex adjusted prevalence and incidence rates were calculated for each community from 1991 to 2002 and the development of an economic change indicator defined using Census data and industry/government documents allowed for yearly assessment of community-level exposure to economic conditions. The relationship between exposure to economic change and rates of acute and chronic cardiovascular disease and mental disorders across the 29 study communities was investigated using a generalized linear model (stratified by type of community, and adjusted for the effect of the community). Findings indicate an impact on the prevalence rates for acute cardiovascular disease (CVD) during periods of economic decline (rate increased by 13.1 cases per 1,000 population, p < 0.0001 as compared with stable periods) and bust conditions (rate increased by 30.1 cases per 1,000 population, p < 0.0001 as compared with stable conditions) and mental disorders (rate increased by 13.2 cases per 1,000 population, p = 0.0001) in mining communities during declining economic conditions as compared to steady periods of mining employment. This is not observed in other resource-based communities. The paper concludes by highlighting implications for the mining industry to consider as they begin to recognize and commit to mining community health. Minerals 2011-10-28 1 1 Article 10.3390/min1010030 30 48 2075-163X 2011-10-28 doi: 10.3390/min1010030 Janis Shandro Mieke Koehoorn Malcolm Scoble Aleck Ostry Nancy Gibson Marcello Veiga http://www.mdpi.com/2075-163X/1/1/3 Despite undeniable progress, the mining industry remains the scene of serious accidents revealing disregard for occupational health and safety (OHS) and leaving open the debate regarding the safety of its employees. The San José mine last collapse near Copiapó, Chile on 5 August 2010 and the 69-day rescue operation that followed in order to save 33 miners trapped underground show the serious consequences of neglecting worker health and safety. The aim of this study was to validate a new approach to integrating OHS into risk management in the context of a new open-pit mining project in Quebec, based on analysis of incident and accident reports, semi-structured interviews, questionnaires and collaborative field observations. We propose a new concept, called hazard concentration, based on the number of hazards and their influence. This concept represents the weighted fraction of each category of hazards related to an undesirable event. The weight of each category of hazards is calculated by AHP, a multicriteria method. The proposed approach included the creation of an OHS database for facilitating expert risk management. Reinforcing effects between hazard categories were identified and all potential risks were prioritized. The results provided the company with a rational basis for choosing a suitable accident prevention strategy for its operational activities. Minerals 2011-09-22 1 1 Article 10.3390/min1010003 3 29 2075-163X 2011-09-22 doi: 10.3390/min1010003 Adel Badri Sylvie Nadeau André Gbodossou http://www.mdpi.com/2075-163X/1/1/1 In recent decades, excellent progress has been made globally in finding mineral resources, extracting them efficiently and effectively, dramatically reducing environmental degradation, and preventing adverse health and safety impacts on workers and stakeholders. The industry has realized tremendous advances in technology and applied science; has met changing and more stringent environmental performance criteria; has made remarkable reductions in fatality, illness, and lost-time accident rates; and has connected better than ever before with the communities in which mining, milling, and smelting are housed. A new era focused on continuous improvement in tackling key sustainable development parameters has come and is intensifying [1].  In order to maintain the social licenses needed to enlist broad public support for mining businesses, continued progress must be visible to national, provincial, and local governments as well as the people who live in the areas blessed with the mineral resources that the global economy and growing population will demand. [...] Minerals 2010-10-12 1 1 Editorial 10.3390/min1010001 1 2 2075-163X 2010-10-12 doi: 10.3390/min1010001 R. Larry Grayson