Major Minerals Research Articles

Thermal-Infrared Spectral Feature Analysis and Spectral Identification of Monzonite Using Feature-Oriented Principal Component Analysis

Rock spectral analysis is an important research field in hyperspectral remote sensing information processing. Compared with the spectra in the short-wave infrared and visible–near-infrared regions, the emittance spectrum of rocks in the thermal infrared (TIR) region is highly significant for identifying some major rock-forming minerals, including feldspar, biotite, pyroxene and hornblende. Even for the same rock type, slight differences in mineral composition generally result in varying spectral signatures, undoubtedly increasing the difficulty in discriminating rock types on the Earth’s surface via TIR spectroscopy. In this study, amounts of monzonite samples from different regions were collected in the central part of Hunan Province, China, and emission spectra at 8–14 μm were measured using a portable thermal infrared spectrometer. The experimental result illustrates 13 remarkable feature positions for all the monzonite samples from different geological environments. Furthermore, by combining the extracted features with the principal component analysis (PCA) method, feature-oriented PCA was applied to establish a model for identifying monzonite accurately and quickly without performing spectral library matching and spectral deconvolution. This study provides an important method for rock type identification in the TIR region that is helpful for the rock spectral analysis, geological mapping and pixel unmixing of remote sensing images.

Technology, geography, and diversification in a small mineral economy

When should a policymaker promote economic diversification in resource-rich regions? What are the necessary structural economic conditions for such policies to work? How compatible are regional and national strategies of diversification? This study focuses on the general equilibrium properties of policies that aim to diversify the economic structure of regions through productive linkages with the resource sector. Using Chile, a major mineral exporter, as a case study, and exploiting variation induced by the expansion of the mining industry and the commodity prices super-cycle, we analyze how a shock in the resource sector affects other sectors and regions through productive linkages. The results are utilized in simulating the economic conditions under which regional diversification is an optimal strategy for resource-based economic development. Our results support the need for a multiscalar approach for resource-driven economic development policies by showing that optimal outcomes of diversification policies on economic growth are found when policies combine regional, sectoral, and national strategies for development.

Integrative Study of Coastal Land-Based Pollution and Effects: Focus on Soil Properties

The discharge and dumping of untreated domestic and industrial wastes into estuaries, rivers, and nearshore waters are the principal sources of coastal pollution in the current study area. Ten soil samples were collected near the industry pollutant exit point near the seashore and towards Mangalore city and were undergo chemical and physical analysis. Also, both distilled water and seawater were used to determine the strength characteristics of the samples. SEM, XRD and EDS were used to determine the surface morphology, chemical compositions of samples. From the results, it was found that most of the samples collected were more or less not met the sufficient range for the agricultural activities. When soil samples undergo Compaction and UCS tests in the presence of seawater and distilled water, MDD and UCS values were decreased in the presence of seawater. From the SEM study, the majority of samples have crystalline texture. Carbon, Oxygen, Aluminium, Silicon, Iron and Mercury were major elements abundantly found in the collected soil samples when it undergoes EDS Analysis. From the XRD analysis, it was known that Quartz, illite, kaolinite, orthoclase, mica, halloysite are the major mineral compounds found in the collected soil samples.

Saharan Dust Deposition in Central Europe in 2016—A Representative Year of the Increased North African Dust Removal Over the Last Decade

Changes in circulation patterns associated with climate change have led to an increase in the frequency and intensity of Saharan dust events (SDEs) in the Carpathian Basin. The annual number of dust events was 4.2 on average between 1979 and 2010, while in the period of 2011–2018, it has increased to 10.3. This study presents a quantitative assessment of wet deposition of dust particles to Lake Balaton (Central Europe) with mineralogical and particle size distribution measurements. In addition to a comprehensive, systematic SDE identification process, rainwater samples were collected in 2016, and the particles on the filters were characterised using a range of analytical techniques. The atmospheric transport of particulates and moisture was evaluated using HYSPLIT Lagrangian trajectory model. XRD measurements revealed that during these events, the major minerals were quartz, kaolinite and 10-Å phyllosilicates. In addition, mineralogical source markers of arid dust (palygorskite and smectite) were also identified in majority of the analysed samples. Based on the results, wet deposition fluxes of dust particles were estimated for the region. 2016 was a typical and representative year for the decade, with twelve identified dust episodes. The synoptic patterns of the events fit well with the typical meteorological character of the North African dust intrusions with enhanced atmospheric meridionality described earlier. From the twelve episodes of 2016, seven were depositional events when wet deposition could be observed at ground level. Dust material of five episodes was analysed in detail, while particles of the two February wet deposition episodes were only granulometrically characterised. General uncertainties that hinder the characterisation of mineral dust in climate models were also observed in the granulometric and dust flux data of the sampled material. The particle size of the deposited dust was coarser than the upper cut-off level of grain size of the models. In addition, the discrepancies between measured and simulated deposition values clearly demonstrated the incorrect representation of dust flux in numerical simulations (partly due to inaccurate grain size data in the models).

Mineralogical Characteristic and Beneficiation Evaluation of a Ta-Nb-Li-Rb Deposit

In order to rationally develop and utilize a Ta–Nb–Li–Rb rare metal deposit in Jiangxi Province, the mineralogical characteristics of the ore, such as chemical composition, mineral composition, modes of occurrence of major elements, and dissemination characteristics of major minerals, were investigated in detail based on optical microscopy analysis, chemical analysis, X-ray diffraction analysis, artificial panning, mineral liberation analysis, and electron probe microanalysis. The results reveal that the main useful elements in the ore are tantalum, niobium, lithium, and rubidium. Niobium and tantalum are mainly found in the mineral form of columbite. Columbite has particle sizes ranging from 0.5 mm to 0.012 mm, with the most common sizes being 0.3 to 0.044 mm. Intergranular dispersion accounts for 73.92% of the embedding in columbite, whereas inclusions account for 26.08%. Lithium is found mostly in zinnwaldite, while rubidium is found primarily in feldspar and zinnwaldite, both in a homogenous distribution. The beneficiation evaluation of this ore was conducted based on the mineralogical characteristic, and it indicates that the tantalum-niobium–lithium–rubidium rare metal resources, as well as the feldspar and quartz non-metallic resources in the ore, can be effectively and comprehensively recovered using gravity, magnetic, and flotation separation methods. A staged grinding and separating process was adopted which could produce tantalum–niobium mineral concentrates (18.34% Ta2O5 at a recovery of 47.65% and 41.33% Nb2O5 at a recovery of 69.96%), zinnwaldite concentrate (2.41% Li2O and 0.80% Rb2O at a recovery of 81.82%) and other concentrates such as cassiterite, topaz, galena, sphalerite, and feldspar. This study provides suggestions for the rational development and utilization of the deposit and provides a reasonable level of recovery prediction.

Genesis and possible applications of Lwamondo and Zebediela Kaolins, Limpopo Province, South Africa

ABSTRACT The genesis and potential industrial applications of Lwamondo and Zebediela Kaolins in South Africa were determined. Selected physico-chemical characteristics were determined. Mineralogical characteristics were determined using XRD and SEM; and geochemical characteristics were determined using XRF and LA-ICP-MS. Kaolin colours were generally light (Lwamondo) and brown (Zebediela). Both kaolins had low pH (<6.5) and EC (<50 µS/cm). The texture of Lwamondo Kaolin was generally loam and clay loam, whereas that of Zebediela was clayey, silty and loamy. Major mineral phases were kaolinite, smectite and plagioclase in Lwamondo Kaolin, and kaolinite in Zebediela Kaolin. The morphology of the kaolins consisted mainly of stacks of kaolinite flakes. The most dominant major oxides were SiO2, Al2O3 and Fe2O3, and the kaolins were slightly depleted in light rare earth elements. The studied characteristics indicated that the kaolins (i) formed in a supergene environment and (ii) are suitable for hollow bricks.

Comparison of Phytochemicals in Sesame and Perilla (Seeds and Oils) Grown at Mae Hong Son Thailand

Abstract Sesame and perilla seeds were analyzed for fat, protein, moisture and ash. Their mineral contents, lignan, γ-tocopherol and fatty acid profiles were also determined. The results showed that sesame seeds had higher protein, lipid and mineral contents but lower fiber contents than perilla seeds, accounting for 17.38-20.76%, 42.70-46.18%, 3.07-6.47%, 18.00-21.88%, respectively. Major minerals in the seed were 0.26-0.95% calcium and 0.11-0.23% magnesium. Perilla oil showed lower pH than sesame oil giving it higher acid value. Most lignans were more concentrated in sesame than perilla. Sesamin was the predominant lignin, followed by sesamolin. The sesamin and sesamolin contents in sesame were ranged for 148.30-183.68 mg/100g and 33.96-43.54 mg/100g, respectively. Although black sesame oil had low content of sesamin and sesamolin, it performed high physiological functions due to its high contents of γ-tocopherol and unsaturated fatty acid. Gamma tocopherol of the oils was ranged from 35.81 to 51.64 mg/100g, and perilla oil showed the highest γ-tocopherol content. Fatty acid profiles revealed that the major fatty acids in sesame oils were 44.43-47.21% linoleic followed by 36.40-38.39% oleic, 7.07-9.64% palmitic and 5.09-7.72% stearic acids, giving them high polyunsaturated fatty acids (PUFA), followed by monounsaturated fatty acids (MUFA) and saturated fatty acids (SFA). White sesame oil had higher linoleic acid but lower oleic acid than other sesame oils. Perilla oil contained high amounts of 55.27% α-linolenic followed by 19.75% linoleic, 12.70% oleic and 7.38% plamitic acids, giving it high PUFA, but low SFA and MUFA. Keywords: Chemical composition, Minerals, Fatty acid profiles, Lignans, Gamma-tocopherol

Mneralogy of the Vorontsovskoe gold deposit (Northern Urals)

The Vorontsovskoe gold deposit (Northern Urals) is unique in both Russia and the world because of the diverse and original Tl–Hg–Mn–As–Sb–S mineralization. Based on the available literature and our data, we present a list of 210 minerals found at this deposit. Eight of them are new minerals discovered by the authors: vorontsovite, ferrovorontsovite, tsygankoite, gladkovskyite, luboržákite, pokhodyashinite, gungerite, and auerbakhite. In addition, 41 minerals are found for the frst time in the Russian Federation and 89 minerals are new for the deposit. We defned nine major ore mineral assemblages, including seven ones related to carbonate breccias. They contain more than 70 rare sulfdes, tellurides and sulfosalts, including 31, 12, and 9 minerals with Tl, Hg and Mn, respectively, as species-defning elements. The paper also describes these mineral assemblages and minerals of the Vorontsovskoe deposit. Keywords: Vorontsovskoe deposit, Northern Urals, ore mineral assemblage, carbonate breccia, Tl-Hg-Mn sulfosalt, new mineral, frst fnd in Russia.

Bioactive components, antibacterial and antiradical properties of home-made apple and grape vinegar

The present study aimed to investigate major volatile compounds, organic acid, phenolic and mineral contents, and antiradical and antimicrobial properties of home-made apple/grape vinegar. Grape vinegar showed higher total acidity, organic acid content, total phenolic content (TPC), antiradical activity and lower minimum inhibitory concentration (MIC) values compared to apple vinegar. While acetic and tartaric acids were the most abundant organic acids in grape vinegar, acetic and succinic acids were the most abundant organic acids in apple vinegar. The most abundant phenolic compound was gallic acid in both grape and apple vinegar. A total of 18 and 9 volatile compounds were determined in grape vinegar samples and apple vinegar samples, respectively. The most abundant volatile compounds were acetic acid and acetoin in grape vinegar, acetic acid, ethyl acetate and 2,4,5-trimethyl-1,3-dioxolane in apple vinegar. K, Ca and Na were common minerals in both vinegar and more in the grape vinegar compared to apple vinegar. Although MIC value for grape vinegar was at 6.25% with minimum bactericidal concentration (MBC) values ranged from 6.25% to 12.50%, MIC value for apple vinegar was at 12.50% with MBC values ranged from 12.50% to 25.00% for all test bacteria. The antiradical and antibacterial activities of the vinegar samples were correlated with their TPC and organic acid contents.

Rate and capacity of cation release from ultramafic mine tailings for carbon capture and storage

Solid wastes produced during hard-rock mining have capacity to capture and store atmospheric CO2 via dissolution and precipitation of Mg-bearing carbonate minerals. However, there is a discrepancy in our understanding of weathering and dissolution in these wastes, with dissolution and reaction rates in field studies exceeding those predicted by experiments under far-from-equilibrium conditions. To reconcile these differences, a series of flow-through dissolution experiments at 25 °C and 1atm were performed to investigate the short-term dissolution kinetics of ultramafic tailings and minerals. Results show that mineral and tailings samples have two stages of dissolution: a fast, transient (or labile) stage, and a slow, stoichiometric stage. Fast releasing labile cations (i.e. labile Mg2+) are sourced from trace minerals with a high reaction rate (e.g. brucite) and from non-stoichiometric surface reaction processes of major minerals (e.g. serpentine). These cations are missing from most geochemical models for mineral weathering. The implication of these results is that the initial transient dissolution of minerals, which is typically ignored during geochemical investigations into bulk dissolution rates, is the missing ingredient for understanding dissolution of mine tailings. Labile cations released during the initial transient dissolution process have value for rapid and low-cost carbon capture and storage techniques as they represent reactivity, capacity, and the best opportunities to deploy low-cost carbon sequestration techniques using mine tailings and other industrial wastes. The presence of labile cations and changing reaction rates over time may also suggest that short-term reactivity examined during field tests may overestimate long-term carbon capture potential of some sites.

Zoisite in cratonic eclogite xenoliths - Implications for water in the upper mantle

A significant portion of the Earth's water is found at trace levels in nominally anhydrous rock forming minerals in the crust and mantle. Its distribution has far-reaching implications in melt-generating processes, mantle rheology and the stability of the lithosphere. We report petrographic, major and trace element, Fourier transform infrared spectroscopy and secondary ion mass spectrometry data on four eclogite xenoliths from the Obnazhennaya kimberlite, Siberia that contain hydrous minerals at upper mantle conditions. Al-rich (>9.9 wt% Al2O3) omphacitic clinopyroxene, a major mineral of eclogites, contains crystallographically controlled exsolutions of CaO-rich (up to 23.6 wt%) garnet (coronae, lenses), garnet-zoisite (lamellae) or amphiboles (needle/blade-like exsolutions). The omphacite hosting the exsolved lamellae shows enrichment or depletion in major (Al, Si, Mg) and trace (e.g., HREE) elements compatible with garnet and zoisite, proportional to the abundance of exsolutions.We argue that zoisite likely formed concomitantly with garnet exsolution from a water- and Al-rich precursory omphacite, without any fluid addition. The compositional gradients are consistent with diffusion-controlled partitioning in a closed system, and their preservation indicates the exsolution likely took place shortly prior to eclogite entrapment by the kimberlite. Large, non-exsolved, omphacite grains contain minimum ~870–1500 ppm wt. H2O (determined as OH). We infer that intertwined lamellae of hydrous garnet (600–960 ppm wt. H2O) and minor (<1%) zoisite (2 wt% H2O) formed at mantle conditions due to progressive exsolution, without external fluids. Recalculated whole rock water contents range from ~320 to 970 ppm wt. H2O. These estimates exceed by far those for the surrounding peridotitic mantle and suggest that, although a minor component, eclogites may locally be an important water reservoir in the cratonic mantle.

Analysis and experimental investigation of Apollo sample 12032,366‐18, a chemically evolved basalt from the Moon

Abstract Sample 12032,366‐18 is a 41.2 mg basaltic rock fragment collected during the Apollo 12 mission to the Moon. It is enriched in incompatible trace elements (e.g., 7 ppm Th), but does not have a bulk composition that would be considered a KREEP (enriched in potassium, rare earth elements, and phosphorous) basalt. The sample is of particular interest because it may be representative of some of the mare basalts within Oceanus Procellarum that are inferred to be Th‐rich, based on remote sensing data. The major mineral assemblage of 12032,366‐18 is pyroxene, plagioclase, olivine, and ilmenite, and the bulk composition has 4.2 wt% TiO2, 11.7 wt% Al2O3, and 0.25 wt% K2O. The sample contains regions of late‐stage crystallized minerals and glass (collectively termed mesostasis), including K‐feldspar, apatite, rare earth (RE) merrillite, ilmenite, troilite, silica, and relatively sodic plagioclase adjacent to ferroan pyroxene. The mesostasis also occurs in several areas that are highly enriched in silica and intergrown with K‐feldspar and very fine‐grained, high‐mean‐atomic‐number phases. We explore the petrology of this sample, including the origin of the Si‐K‐rich mesostasis to assess whether the mesostasis had formed by silicate liquid immiscibility (SLI). We used experiments to determine if the bulk composition of 12032,366‐18 is representative of a bulk liquid composition, how the residual liquid evolves, and to investigate the partitioning of elements between phases as the melt evolves. Experiments support that the mesostasis formed by SLI after crystallization of minerals closely matches the major‐mineral assemblage of 12032,366‐18. Experiments bracket the onset of SLI and merrillite saturation between 1024 and 1002 °C. Some high field strength elements, such as Zr and P, partition preferentially into the Fe‐rich liquid. From the experiments, we infer that the bulk composition of 12032,366‐18 represents the magma from which it crystallized. Based on the Th‐rich and KREEP‐bearing chemistry of this sample, along with experimental evidence showing that the sample is representative of a bulk liquid composition and not a cumulate, we conclude that basalt fragment 12032,366‐18 was delivered to the Apollo 12 landing site as ejecta from a distant impact and could represent an Oceanus Procellarum basalt. Missions to Oceanus Procellarum, such as Chang’E 5, have the potential to confirm whether some of those basalts are indeed enriched in Th and other incompatible trace elements as indicated by remote sensing.

High thermal conductivity of stishovite promotes rapid warming of a sinking slab in Earth's mantle

Thermal transport in subducted slabs and mantle critically influences their thermo-chemical evolution and dynamics, where the thermal conductivity controls the magnitude of conductive heat transfer. Here we investigate high-pressure thermal conductivities of stishovite and new-hexagonal-aluminous (NAL) phase, two major slab minerals in the shallow lower mantle, and their impacts on slab dynamics. Pure and Al-bearing stishovite exhibit conductivities of 60–70 and 30–40 Wm−1K−1, respectively, at 25–60 GPa and 300 K, much higher than the Fe-bearing NAL, 10–33 Wm−1K−1, and assemblage of a pyrolitic mantle or subducted basaltic crust. Numerical simulations indicate that subducted crustal materials particularly with local silica-enrichment would have efficient thermal conduction which promotes faster warming of a sinking slab, altering dynamic stability of slab materials and leading to slab stagnation and crust detachment in the shallow lower mantle. Conductive heat transfer in silica-enriched regions along subducted slabs in the shallow lower mantle can be more influential on mantle dynamics than previously thought.

Applications of Radial Basis Functional Link Networks in the Exploration for Lala Copper Deposits in Sichuan Province, China

The Lala copper area in Huili County, Sichuan Province, China, is favored by superior regional metallogenic geological conditions due to its location in an extremely important copper–iron metallogenic belt in southwest China, and it has witnessed the formation of a series of unique iron–copper deposits following the superposition of multiple tectonic events. In recent years, major mineral exploration breakthroughs have been achieved in the deep and peripheral zones of this area. Using the Lala copper mining area in Sichuan as an example, this paper describes metallogenic prediction research carried out based on multivariate geoscience information (geological information, geophysics, geochemistry, and remote sensing data) and the application of geographic information system (GIS) technology and the radial basis function neural network (RBFLN) model. The five specific aspects covered in this paper are as follows: (1) we collected geology–geophysics–geochemistry remote sensing data and other information, adopted GIS technology to extract multivariate geoscience ore-forming anomaly information, and established a geoscience prospecting information database; (2) we applied the RBFLN algorithm for information on integrated analysis of ore-forming anomalies in the study area; (3) we applied a statistical method to divide the threshold value to delineate favorable ore-prospecting target areas; (4) we applied three-dimensional (3D) visualization technology, through which sample assistance was verified, to evaluate the performance of the RBFLN model; and (5) the results revealed that the RBFLN model can integrate multivariate and multi-type geoscience information and effectively predict metallogenic prospective areas and delineate favorable target areas. The metallogenic prediction method based on RBFLN technology provides a scientific basis for the exploration and deployment of minerals in the study area. It is obvious that the methods to predict and evaluate mineral resources are developing towards model integration and information intelligent analysis.

Requirement, Dietary Sources, and Efficiency of Absorption of Major Minerals by Farm Animals: From an Educational Perspective

The necessity of the inclusion of major minerals in the diet of farm animals cannot be overemphasized. The production of the much-needed animal protein can be severely hampered when unrecognized conditions of deficiency, oversupply, or in-balance of minerals exist and interfere with the intensification of livestock production. Here, the purpose of this study was to explain this matter based on an educational perspective. This paper is a literature survey. This paper is important to make farmers understand the requirement, dietary sources, and efficiency of absorption of major minerals by farm animals. For the best production of any livestock, the requirement for each mineral must be known. Lack of adequate minerals in the diet of farm animals is associated with late maturity, prolonged breeding period, reproductive disorders, poor growth, anemia, and a high rate of mortality.

Improvement towards Prediction Accuracy of Principle Mineral Resources Using Threshold

The production data of mineral resources are noisy, nonstationary, and nonlinear. Therefore, some techniques are required to address the problem of nonstationarity and complexity of noises in it. In this paper, two hybrid models (EMD-CEEMDAN-EBT-MM and WA-CEEMDAN-EBT-MM) flourish to improve mineral production prediction. First, we use empirical mode decomposition (EMD) and wavelet analysis (WA) to denoise the data. Second, ensemble empirical mode decomposition (EEMD) and complete ensemble empirical mode decomposition (CEEMDAN) are used for the decomposition of nonstationary data into intrinsic mode function (IMF). Then, empirical Bayesian threshold (EBT) is applied on noise dominant IMFs to consolidate noises, which are further used as input in the data-driven model. Next, other noise-free IMFs are used in the stochastic model as input for the prediction of minerals. At last, the predicted IMFs are ensemble for final prediction. The proposed strategy is exemplified using Pakistan's four major mineral resources. To measure the prediction performance of all the models, three methods, that is, mean relative error, mean square error, and mean absolute percentage error, are used. Our proposed framework WA-CEEMDAN-EBT-MM has shown improvement with minimum mean absolute percentage error value compared to other existing models in prediction accuracy for all four minerals. Therefore, our proposed strategy can predict the noisy and nonstationary time-series data with an efficient mechanism. Hence, it will be helpful to the policymakers for making policies and planning in mineral resource management.

A comprehensive and internally consistent mineral dissolution rate database: Part I: Primary silicate minerals and glasses

Mineral dissolution rates control the temporal evolution of many natural processes on the surface and upper crust of the Earth. This is the first of a series of papers describing the development and implementation of a comprehensive and internally consistent database of the dissolution rates of the major rock-forming minerals. In this paper, we describe the retrieval and regression of the dissolution rates of the primary rock-forming silicates, including quartz and other SiO2 polymorphs, feldspars, pyroxenes, amphiboles, micas, volcanic glass, and olivines. Owing to the limited fluid chemistry data available for many of the published experimental studies, BET surface area normalized mineral and most glass dissolution rates (r) were regressed usingr=∑iAiaH+nieEaiRT1−exp−AσRTwhere Ai stands for pre-exponential factors, aH+ corresponds to the hydrogen ion activity, ni refers to reaction orders, T designates absolute temperature, R denotes the gas constant, Eai represents activation energies, σ stands for Temkin's average stoichiometric number, and A denotes the chemical affinity of the dissolution reaction. Where relevant data were lacking, rates were extrapolated assuming that mineral dissolution follows similar trends within the same mineral group. Regression was performed using least-squares algorithms. The average difference between calculated and measured rates ranged from 0.1 to 0.7 log units depending on the mineral. The obtained rate equations were implemented into the carbfix.dat database for direct use in the PHREEQC software but can be extended to other geochemical modeling software, such as TOUGHREACT.

Antimicrobial potential of four mica drugs and their chemical and mineralogical properties

BackgroundMica drugs, a group of herbo-metallic traditional preparations comprising biotite mica as the major mineral ingredient, are prescribed for skin disorders and respiratory ailments and other chronic conditions in South Asian countries, particularly India and Sri Lanka. Mica-based drugs (Abhrak drugs) are subjected to unique and varied preparation procedures and the bioactivity of the drugs can be affected by drug-processing conditions, the ingredients used and the mica composition. The current study aimed to evaluate and compare, on the basis of their physical and chemical characteristics, the antimicrobial potential of two commercial mica drugs AbBb (Abhrak bhashma) and AbCh (Abhrak Chenhuram) and two mica drugs ABL1 (Abhrak Bhasma Laboratory Prepared 1) and ABL2 (Abhrak Bhasma Laboratory Prepared 2) prepared in the laboratory under different conditions.MethodsAntimicrobial activity of all four drugs was assessed at 10 mg/ml concentration against Pseudomonas aeruginosa, Escherischia coli, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA) and Candida albicans using well diffusion assay, agar dilution assay and Miles and Misra method. Major and trace metal constituents of the drug samples were measured using atomic absorption spectrometry. Mineralogical properties, bacteria-mineral interactions, morphological changes in microbes and the surface characteristics of the drugs were determined using X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM).ResultsThe drugs ABL1, ABL2 and AbBh exhibited antimicrobial activity against only Gram-positive organisms (S. aureus and MRSA) when tested with Miles and Misra method (broth method). Mineralogical studies (XRD) revealed that biotite mica was altered into secondary clay minerals and iron oxides in the commercial drug AbCh while the other three drugs had altered mica and iron oxide phases. The essential elements (Na, K, Ca and Mg) required for microbial functions were present in varying extents in all four drugs while they were present in exceedingly high amounts in AbCh having comparatively high cation-exchange capacity, consistent with the observation that AbCh was inactive against all the microbes tested. The three drugs (ABL1, ABL2 and AbBh) showing antimicrobial activity contained comparatively high amounts of Fe, Zn and Cu that are known to display antimicrobial properties at high concentrations. SEM studies revealed that the drug particles adhered and entrapped the bacterial species, presumably modifying the physiochemical characteristics of the bacteria and eventually causing lethality.ConclusionThree of the four mica drugs inhibited the tested Gram-negative bacteria and the antibacterial activity of the mica drugs depends on their constituents and the methods of preparation.

Resource Assessment and Possible Industrial Applications of Bauxite Occurrences in Parts of the Mambila Plateau, NE Nigeria

Bauxites are normally formed from underlying aluminosilicate rocks as a result of tropical weathering. In our previous 2 papers, we presented the Geology, possible host, mineralogy, and geochemistry of the bauxites of Mambila Plateau, NE Nigeria. The bauxite was formed from residual chemical weathering of trachyte and occurs as a blanket cover over saprolite. XRD results showed gibbsite as the major mineral with small amounts of hematite, kaolinite, and quartz. Geochemistry of the bauxite ore is characterized by enriched Al2O3 (39.50-78.20.0%), erratic amounts of SiO2 (2.89-5.13%) and Fe2O3 (5.98-21.96%). In this study, the resources of Mambilla Bauxite Deposits (Block I and Block II) have been estimated to be 7,529,312.5 metric tons using block method of vertical geological cross-section bearing in mind that the Mambilla Bauxite Deposits have been explored by pitting on a regular grid pattern of 100 m×100 m. The bauxite deposit in Block II has met the requirement for metallurgical grade bauxite as standard specification (IS: 5953-1985, Reaffirmed [1]). While, Block I deposit has not met such specifications. Sustained investment in bauxite exploration is required to upgrade the ore reserves for sustainable development of a mining enterprise.

Mineralogy of beach sand in Jumundo, Korea and recovery of heavy minerals using Humphreys spiral concentrator and shaking table followed by magnetic separation process

ABSTRACT The mineralogy of beach sand, which was sampled from an island, Jumundo of South Korea, was investigated and beneficiated using gravity and magnetic separation processes. Ilmenite was determined to be a major heavy mineral and, as minor heavy minerals, zircon, monazite, and sphene were observed. Quartz, biotite, microcline, kaolinite, hornblende, and chlorite were present as gangue minerals. The Ilmenite was concentrated with a Humphrey spiral concentrator and shaking table followed by magnetic separators (drum and cross belt types). As a final product, 18% of the Humphrey spiral system concentrate was recovered, and the grade of final product was determined to be 93% ilmenite. The electron probe microscope analysis indicates that ilmenite was a solid solution of major FeTiO3, minor MgTiO3 (geikielite), and MnTiO3 (pyrophanite).