THE CRYSTAL STRUCTURE OF A MICROLITE-GROUP MINERAL WITH A FORMULA NEAR NaCaTa(2)O(6)F FROM THE MORRO REDONDO MINE, CORONEL MURTA, MINAS GERAIS, BRAZIL

We present electron-microprobe and single-crystal X-ray-diffraction data for a microlite-group mineral with a formula near NaCaTa(2)O(6)F from the Morro Redondo mine, Coronel Murta, Minas Gerais, Brazil. On the basis of these data, the formula is A(Na(0.88)Ca(0.88)Pb(0.02)square(0.22))(Sigma 2.00) (B)(Ta(1.70)Nb(0.14)Si(0.12)As(0.04))(Sigma 2.00) (X)[(O(5.75)(OH)(0.25)](Sigma 6.00) (Y)(F(0.73)square(0.27))(Sigma 1.00). According to the new nomenclature for the pyrochlore-supergroup minerals, it is intermediate between fluornatromicrolite and "" fluorcalciomicrolite"". The crystal structure, F (d3) over barm, a = 10.4396(12) angstrom, has been refined to an R(1) value of 0.0258 (wR(2) = 0.0715) for 107 reflections (MoK alpha radiation). There is a scarcity of crystal-chemical data for pyrochlore-supergroup minerals in the literature. A compilation of these data is presented here.

Mineralogy and trace-element geochemistry of the high-grade iron ores of the Aguas Claras Mine and comparison with the Capao Xavier and Tamandua iron ore deposits, Quadrilahero Ferrifero, Brazil

Several major iron deposits occur in the Quadrilatero Ferrifero (QF), southeastern region of Brazil, where metamorphosed and heterogeneously deformed banded iron formation (BIF) of the Caue Formation, regionally called itabirite, was transformed into high- (Fe >64%) and lowgrade (30%mineralogical composition, three major types of itabirites occur in the QF: siliceous, dolomitic, and amphibolitic itabirite. Unlike other mines in the QF, the Aguas Claras Mine contained mainly high-grade ores hosted within dolomitic itabirite. Two distinct types of high-grade ore occurred at the mine: soft and hard. The soft ore was the most abundant and represented more than 85% of the total ore mined until it was mined out in 2002. Soft and hard ores consist essentially of hematite, occurring as martite, anhedral to granular/tabular hematite and, locally, specularite. Gangue minerals are rare, consisting of dolomite, sericite, chlorite, and apatite in the hard and soft ores, and Mn-oxides and ferrihydrite in the soft ore where they are concentrated within porous bands. Chemical analyses show that hard and soft ores consist almost entirely of Fe(2)O(3), with a higher amount of detrimental impurities, especially MnO, in the soft ore. Both hard and soft ores are depleted in trace elements. The high-grade ores at the Aguas Claras Mine have at least a dual origin, involving hypogene and supergene processes. The occurrence of the hard, massive high-grade ore within ""fresh"" dolomitic itabirite is evidence of its hypogene origin. Despite the contention about the origin of the dolomitic itabirite (if this rock is a carbonate-rich facies of the Caue Formation or a hematite-carbonate precursor of the soft high-grade ore), mineralogical and geochemical features of the soft high-grade ore indicate that it was formed by leaching of dolomite from the dolomitic itabirite by meteoric water. The comparison of the Aguas Claras, Capao Xavier and Tamandua orebodies shows that the original composition of the itabiritic protore plays a major role in the genesis of high- and low-grade soft ores in the QF. Under the same weathering and structural conditions, the dolomitic itabirite is the more favorable to form high-grade deposits than siliceous itabirite. Field relations at the Aguas Claras and Capao Xavier deposits suggest that it is not possible to form huge soft high-grade supergene deposits from siliceous itabirite, unless another control, such as impermeable barriers, had played an important role. The occurrence in the Tamandua Mine of a large, soft, high-grade orebody formed from siliceous itabirite and closely associated with hypogene hard ore suggests that large, soft, high-grade orebodies of the Quadrilatero Ferrifero, which occur within siliceous itabirite, have a hypogene contribution in their formation.

Guides of the Falu Mine : Perceptions of Differences and Similarities onDomestic and International Visitors

Industrial heritage tourism has been in focus for many academic studies and tourism is an alternative developmental tool for mines and contributes to their economic success. This thesis is about the Falu Mine in Dalarna, Sweden, which has World Heritage status since 2001 and is one of the biggest attractions in the region. Its history and cultural importance are reasons for the importance of preserving the heritage. The Falu Mine is under the management of the Great Copper Mountain Trust and one of their ambitions is to ensure the continuous popularity among domestic and international visitors. In order to gain a better understanding of the visitors and to find strategies to improve performance, a visitor survey has been conducted in the summer of 2011. It is the authors believe that the guides of the Falu Mine have the best available insight and that their perceptions help to add to the understanding about the visitors. Therefore, this thesis aims to explore the perceptions of the guides about their visitors, to investigate how the perceptions correspond to the statistical results and to study if there are any differences between domestic and international visitors. The mixed methods approach will increase the depth and accuracy of the results, by linking qualitative with quantitative data. The results show that differences between domestic and international visitors exist, both proven by interviews with the guides and the visitor survey. These differences occur in the factors, such as level of education of the visitors, group size and number of children in the group, knowledge of the visitors prior to and after the visit, sources of information and the fulfillment of the visitor expectations. The perceptions emphasize how these differences impact the guided tours. The guides of the Falu Mine have to be aware of those differences in order to adjust the tour accordingly, as well as the management of the Falu Mine can use this knowledge in order to identify strategies for improving performance.

Winning the Accreditation Game: The Library as Key Player and Hidden Gold Mine

Libraries are a central hub of information resources supporting college and university curricula. Several library strategies, cross-campus collaborations, and philosophical considerations of electronic and print offerings led to successful accreditations in business and engineering programs.

Removal of radionuclides from acid mine waters by retention on adsorbing materials

This study proposes a method for decontamination of acid drainage water from a uranium mine, as an alternative process to lime treatment. The research embodied the recovery of uranium with an ion-exchange resin, treatment of effluent resin with lime, or with inorganic adsorbents and biosorbents. The uranium decontamination level using the resin process was 94% and allowed the recovery of this element as a commercial product. Among the inorganic adsorbents studied, phosphogypsum was effective for Ra-226, Ra-228, and Pb-210 removal. Among the biosorbents, Sargassum sp.was superior in relation to its specific capacity to accumulate and remove Ra-226.

Molecular characterization of Acidithiobacillus ferrooxidans and A-thiooxidans strains isolated from mine wastes in Brazil

Nineteen strains of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans, including 12 strains isolated from coal, copper, gold and uranium mines in Brazil, strains isolated from similar sources in other countries and the type strains of the two species were characterized together with the type strain of A. caldus by using a combination of molecular systematic methods, namely ribotyping, BOX- and ERIC-PCR and DNA-DNA hybridization assays. Data derived from the molecular fingerprinting analyses showed that the tested strains encompassed a high degree of genetic variability. Two of the Brazilian A. ferrooxidans organisms (strains SSP and PCE) isolated from acid coal mine waste and uranium mine effluent, respectively, and A. thiooxidans strain DAMS, isolated from uranium mine effluent, were the most genetically divergent organisms. The DNA-DNA hybridization data did not support the allocation of Acidithiobacillus strain SSP to the A. ferrooxidans genomic species, as it shared only just over 40% DNA relatedness with the type strain of the species. Acidithiobacillus strain SSP was not clearly related to A. ferrooxidans in the 16S rDNA tree.

Geochemical Study of the Itabirite Iron Ores of the Alegria Mine - Quadrilátero Ferrífero, Minas Gerais, Brazil

The iron ores of Alegria mine are composed of itabirites enclosing minor bodies of high-grade ores. The itabirites are classified according to mineralogical composition in five types: martite-rich, goethite-rich, specularite-rich, magnetite-rich and anphibolite-rich ores. The hematites are martite-rich, magnetite-rich, specularite-rich and more rarely, amphibolite-rich. Other classification criteria of the ores are based on the physical properties and the degree of compaction. As such, the itabirites and hematites can be classified as hard, friable and soft types. The mineralogical/textural evolution of the ores is linked to the pressure and temperature conditions that accompanied the tectonic processes in anphibolite facies and the different degrees of subsequent surficial weathering processes. Petrographic and microstructural studies indicate that the magnetite and amphibole bearing itabirites represent the parent rocks that created the other itabirites and that the specularite itabirites and the hard martite types are related to silica dissolution and redeposition in zones of high and low strain. Most of itabirites ores correspond to chert oxide facies banded iron formation, except the goethite and amphibole bearing itabirite that resemble a silicate or oxide-silicate facies with minor carbonate impurities. The great mass and pods of soft martite itabirites are probably shaley oxide facies BIFs with little volcanic contribution. Trace element contents of the Alegria's itabirites show strong dissimilarities with BIFs associated with volcanism (Algoma type), but closely ressemble to the Lake Superior type, with high content in Cr, Co and low V, Ni, Cu and Zn. Although the absolute contents of REE present in the Alegria's itabirites are, in general very low, the pattern when normalised by NASC is similar to the great majority of the Archean and Paleoproterozoic BIFs elsewhere in the world, and characterised by positive Eu anomaly.

Leaching of Ni and Cu from mine wastes (tailings and slags) using acid solutions and A. ferrooxidans

The objective of this work is to evaluate the acidic and biological leaching of tailings containing Ni/Cu from a flotation and smelting plant. Acidithiobacillus ferrooxidans, strain LR, was used for bioleaching at pH 1.8 and chemical controls were run parallel to that. The acidic leaching was done within 48 hours at pH 0.5 and 1.0. In the slag inoculated flasks the redox potential was high (600 mV), thus indicating oxidative bacterial activity, however, the obtained results after 15 days showed only around 13% Ni and 8% Cu extractions, which were not different to those of the controls. For the flotation tailings bioleaching extractions were approximately 45% for Ni and 16% for Cu while differing figures were obtained for the chemical controls. These were 30% and 12% respectively. Here we could observe that the presence of bacterial activity led to a higher solubility of Ni. Acid leaching of slag showed higher nickel and copper extractions: 56% and 24% respectively at pH 0.5 and 21% and 11% at pH 1.0. However, the acid consumption was 320 and 150 Kg/ton of slag, respectively, both much higher than in bacterial assays. These results indicated that Ni and Cu solubilization from the slag is acid dependent no matter the redox potential or ferric iron concentration of the leaching solution. For flotation tailings, acid treatment showed extractions of 23% for Ni and 16% for copper at pH 0.5 and 22% and 28%, respectively at pH 1.0. The acid consumption was also higher: 220 and 120 Kg/ton, at pH 0.5 and 1.0, respectively. Based on own findings we could observe that acid leaching is found to be more effective for slag, though the acid consumption is much higher, while for the flotation tailings, bacterial leaching seems to be the best alternative. © (2009) Trans Tech Publications.

Determination of in situ speciation of manganese in treated acid mine drainage water by using multiple diffusive gradients in thin films devices

Acid mine drainage (AMD) is a serious environmental problem that creates acidic solution with high Mn concentrations. The speciation of residual Mn from AMD after an active treatment involving the addition of a neutralizing agent can reliably evaluate the treatment efficiency and provide knowledge of the Mn species being inputted into the environment. The aim of this study was to evaluate the in situ lability and speciation of Mn using the diffusive gradients in thin films (DGT) technique with treated drainage water from a uranium mine (TAMD). DGT devices with different binding phases (Chelex-100 and P81 and DE81membranes) were used to perform the in situ speciation of Mn. A comparison of the results from deploying DGT in the laboratory and in situ shows that the speciation of Mn in TAMD should be performed in situ. Linear deployment curves (from in situ experiments) indicate that the DGT device containing the Chelex-100 binding phase can be used to evaluate Mn lability in TAMD. The labile Mn fraction (from in situ measurements) obtained using the device containing the Chelex-100 resin ranged from 63 to 81% of the total Mn concentration and, when compared to the speciation obtained using the CHEAQS software, indicated that this device was capable of uptaking the free Mn2+ and a portion of the MnSO4(aq). The values obtained using the DGT technique were compared to those from on site solid phase extraction, and a good agreement was found between the results. The amount of negative Mn species sampled by DE81 device was insignificant (<1.5%) for all of the sites. Sites containing a relatively small amount of Ca (<40mgL-1) and measured using devices containing the P81 membrane agreed with the concentration predicted by the CHEAQS software for positive Mn species (Mn2+ and Mn(OH)+). Nevertheless, the speciation obtained using the CHEAQS software indicated that the concentrations of positive Mn species were underestimated for sites with relatively high Ca concentrations (>150mgL-1), which take place due to the saturation of binding sites in the P81 membrane. © 2013 Elsevier B.V.

Copper ore type definition from Sossego Mine using X-ray diffraction and cluster analysis technique

This paper presents the classification of 110 copper ore samples from Sossego Mine, based on X-ray diffraction and cluster analysis. The comparison based on the position and the intensity of the diffracted peaks allowed the distinction of seven ore types, whose differences refer to the proportion of major minerals: quartz, feldspar, actinolite, iron oxides, mica and chlorite. There was a strong correlation between the grouping and the location of the samples in Sequeirinho and Sossego orebodies. This relationship is due to different types and intensities of hydrothermal alteration prevailing in each body, which reflect the mineralogical composition and thus the X-ray diffractograms of samples.

Different lead sources in an abandoned uranium mine (Urgeirica - Central Portugal) and its environment impact - isotopic evidence

Different lead sources were identified in a large uranium tailings deposit (5Mton) in the Central Region of Portugal using lead isotopic ratios obtained by ICP-QMS. These ratios helped to clarify the different sources of Pb within the tailings deposit and the impact of the tailings on the surroundings. Ten depth profiles were used for isotopic characterization of the tailings deposit; the lead background signature was evaluated in seven regional rocks (granites) and was defined as being 28 +/- 1 mg kg(-1) for Pb bulk concentration and with isotopic ratios of 1.264(2) for Pb-206/Pb-207 and 1.962(7) for Pb-208/Pb-206. In order to understand Pb isotope distribution within the tailings deposit, simple mixing/mass balance models were used to fit experimental data, involving: (1) the background component; (2) uranium ores (pitchblende) characterized by the ratios Pb-206/Pb-207 of 1.914(3) and Pb-208/Pb-206 of 1.235(2); and (3) an unknown Pb source (named 'Fonte 5') characterized by the ratios Pb-206/Pb-207 of 3.079(7) and Pb-208/Pb-206 of 0.715(1). This unknown source showed high radiogenic ratios found in the water of some tailings depth profiles located in a very specific position in the dump. In terms of isotopic characterization, 69% of the deposit material resulted from the background source, 25% from uranium minerals and only 6% from other uranium mines in the region. Finally, the environment impact revealed that the pollution was focused only in the beginning of the stream and not in the surroundings, nor in the groundwater system. The lead in the water was found only in colloidal form with a clear pitchblende signature. Those data revealed possible remobilization phenomena along the bedside and margins of the watercourse.

Assessment of a UASB reactor for the removal of sulfate from acid mine water

A bench-scale Upflow Anaerobic Sludge Blanket (UASB) reactor was used to study the treatment of acid mine drainage through the biological reduction of sulfate. The reactor was fed with acid mine drainage collected at the Osamu Utsumi uranium mine (Caldas, MG, Brazil) and supplemented with ethanol as an external carbon source. Anaerobic granular sludge originating from a reactor treating poultry slaughterhouse wastewater was used as the inoculum. The reactor's performance was studied according to variations in the chemical oxygen demand (COD)/SO42- ratio, influent dilution and liquid-phase recirculation. The digestion of a dilution of the acid mine drainage resulted in a 46.3% removal of the sulfate and an increase in the effluent pH (COD/SO42- = 0.67). An increase in the COD/SO42- ratio to 1.0 resulted in an 85.6% sulfate reduction. The reduction of sulfate through complete oxidation of the ethanol was the predominant path in the reactor, although the removal of COD was not greater than 68% in any of the operational stages. The replenishment of the liquid phase with tap water positively affected the reactor, whereas the recirculation of treated effluent caused disequilibrium and decreased efficiency. (C) 2012 Elsevier Ltd. All rights reserved.

Intracellular biosynthesis and removal of copper nanoparticles by dead biomass of yeast isolated from the wastewater of a mine in the brazilian Amazonia

In this study was developed a natural process using a biological system for the biosynthesis of nanoparticles (NPs) and possible removal of copper from wastewater by dead biomass of the yeast Rhodotorula mucilaginosa. Dead and live biomass of Rhodotorula mucilaginosa was used to analyze the equilibrium and kinetics of copper biosorption by the yeast in function of the initial metal concentration, contact time, pH, temperature, agitation and inoculum volume. Dead biomass exhibited the highest biosorption capacity of copper, 26.2 mg g(-1), which was achieved within 60 min of contact, at pH 5.0, temperature of 30°C, and agitation speed of 150 rpm. The equilibrium data were best described by the Langmuir isotherm and Kinetic analysis indicated a pseudo-second-order model. The average size, morphology and location of NPs biosynthesized by the yeast were determined by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM). The shape of the intracellularly synthesized NPs was mainly spherical, with an average size of 10.5 nm. The X-ray photoelectron spectroscopy (XPS) analysis of the copper NPs confirmed the formation of metallic copper. The dead biomass of Rhodotorula mucilaginosa may be considered an efficiently bioprocess, being fast and low-cost to production of copper nanoparticles and also a probably nano-adsorbent of this metal ion in wastewater in bioremediation process

Biosynthesis and uptake of copper nanoparticles by dead biomass of Hypocrea lixii isolated from the metal mine in the Brazilian Amazon Region

A biological system for the biosynthesis of nanoparticles (NPs) and uptake of copper from wastewater, using dead biomass of Hypocrea lixii was analyzed and described for the first time. The equilibrium and kinetics investigation of the biosorption of copper onto dead, dried and live biomass of fungus were performed as a function of initial metal concentration, pH, temperature, agitation and inoculum volume. The high biosorption capacity was observed for dead biomass, completed within 60 min of contact, at pH 5.0, temperature of 40 °C and agitation speed of 150 rpm with a maximum copper biosorption of 19.0 mg g(-1). The equilibrium data were better described using the Langmuir isotherm and kinetic analysis indicated that copper biosorption follows a pseudo-second-order model. The average size, morphology and location of NPs biosynthesized by the fungus were determined by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM). NPs were mainly spherical, with an average size of 24.5 nm, and were synthesized extracellularly. The X-ray diffraction (XRD) analysis confirms the presence of metallic copper particles. Infrared spectroscopy (FTIR) study revealed that the amide groups interact with the particles, which was accountable for the stability of NPs. This method further confirmed the presence of proteins as stabilizing and capping agents surrounding the copper NPs. These studies demonstrate that dead biomass of Hypocrea lixii provides an economic and technically feasible option for bioremediation of wastewater and is a potential candidate for industrial-scale production of copper NPs.