• Environmental Engineering Research
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• v.24 no.2
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• pp.279-288
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• 2019

To obtain insightful knowledge of geochemical process controlling fluoride enrichment in groundwater of the villages near Shilabati river bank, West Bengal, India, multivariate statistical techniques were applied to a subgroup of the dataset generated from major ion analysis of groundwater samples. Water quality analysis of major ion chemistry revealed elevated levels of fluoride concentration in groundwater. Factor analysis (FA) of fifteen hydrochemical parameters demonstrated that fluoride occurrence was due to the weathering and dissolution of fluoride-bearing minerals in the aquifer. A strong positive loading (> 0.75) of fluoride with pH and bicarbonate for FA indicates an alkaline dominated environment responsible for leaching of fluoride from the source material. Mineralogical analysis of soli sediment exhibits the presence of fluoride-bearing minerals in underground geology. Hierarchical cluster analysis (HCA) was carried out to isolate the sampling sites according to groundwater quality. With HCA the sampling sites were isolated into three clusters. The occurrence of abundant fluoride in the higher elevated area of the observed three different clusters revealed that there was more contact opportunity of recharging water with the minerals present in the aquifer during infiltration through the vadose zone.

• Journal of the Mineralogical Society of Korea
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• v.15 no.3
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• pp.183-194
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• 2002

Biotite and its weathering Products in the weathering Profile of Andong granite were examined using X-ray diffraction, chemical analysis, and electron microscopy. Major weathering product of biotite was oxidized biotite, which is decomposed into kaolinite in the upper part. Discrete vermiculite or hydrobiotite was not detected although minor vermiculite (5%) was randomly interstratified with oxidized biotite. Excess positive charge induced by iron oxidation was balanced by release of Fe (16%) and Mg (12%) from octahedral site and K (13%) from interlayer site. After slight chemical and structural modification induced by iron oxidation, oxidized biotite persists through the weathering profiles with partial decomposition in the upper part of the profile. Formation environments and dissolution experiments of oxidized biotite highly resistant to weathering are required to understand the elemental behavior in the surface environments on the biotite-bearing bedrocks.

• Journal of the Mineralogical Society of Korea
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• v.28 no.2
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• pp.187-193
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• 2015

The purpose of the present study is to trace the provenance of lead raw materials using the lead isotope ratio of 9 lead glasses excavated from the Sarira hole of Mireuksaji stone pagoda and to determine correlation between them and other lead glasses excavated from the Wanggungri site. The results of chemical analysis of the 9 lead glasses show that they are common lead glass system($PbO-SiO_2$) with respect to the contents of PbO (70 wt.%) and $SiO_2$ (30 wt.%). The lead isotope ratios of them plot to northern Korean peninsula when applied to the distribution map of lead isotopes of East Asia. On the other hand, southern Korean peninsula is verified as the main deposits of the lead ore in the distribution map of lead isotopes of South Korea. With respect to the results, it is notable that the provenance of the 9 lead glasses can be very different depending on the distribution map. In addition, a comparative study between them and the lead glasses excavated from the Wanggungri which was built in the same region and period shows that their lead isotopes are highly correlated.

• Journal of the Mineralogical Society of Korea
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• v.26 no.1
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• pp.1-8
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• 2013

This study was carried out to test the possibility of using an environmentally friendly method of leaching silver concentrate from the Samjo mine. The Samjo mine ore contained minerals such as pyrite, chalcopyrite, galena, arsenopyrite, and sphalerite. The concentrate samples tested with the thiourea solution were roasted at $750^{\circ}C$. The results of different experimental conditions showed that the highest silver leaching rate was obtained when the concentration of thiourea was at 0.8 g with ferric sulfate at 0.425 g and the leaching temperature at $60^{\circ}C$. The Ag leaching rate obtained was 91.5% at a pulp density of 10%. However, in the XRD analysis, peaks of pyrite, galena, and hematite were still found in the leached solid residues in which the Ag leaching rate was the highest. it is expected that the unrecovered silver in the solid residue can be lost.

• Journal of the Mineralogical Society of Korea
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• v.9 no.1
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• pp.1-6
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• 1996

Woolastonite from Susan occurs as intercalations in limestone beds of Lower Paleozoic Joseon Supergroup. It is a thermal metamorphic product of impure limestone. Electron microprobe analysis shows that it is considerably pure wollastonite. It has triclinic cell with a=7.932$\AA$, b=7.328$\AA$, c=7.069$\AA$, $\alpha$=89.995$^{\circ}$, $\beta$=$95.255^{\circ}$, and $ \Upsilon=103.367^{\circ}$.Dissolution behaviors of wollastonite have been studied conducting three different dissolution experiments; two different reactions with HC1 (one batch and one re-initialization experiment) and one traction with distilled water. In the batch type powder wollastonite-HCl reaction, pH of solution rapidly increases in the early stage and then its rate of increase slows down to reach plateau resulting in parabolic relationship with time. It is represented by the early rapid rise and fall in pH giving a sharp pH-edge and succeeding slow rise in the re-initialization experiment. The early rapid rise in pH is due to the rapid sorption of H- in solution to oxygens on the reactive surface of wollastonite and the fall in pH means that all reactive surface sites are occupied by H- ions and no more H- adsorption occurs. The slow rise in pH following the pH- edge is due to the dissolution of wollastonite as evidenced by the correlation of pH variation and cation concentration. Dissolution of powder wollastonite in HCl shows linear trend with time. Si is dissolved predominantly over Ca at a constant rate. Ca is dissolved predominantly in the very early stage. Dissolution rate of coarse-grained wollastonite fragments in distilled water is parabolic with times howing a rapid reaction in the early stage and a slow reaction in the advanced stage. The Ca/Si ratio in solution is high in the case of coarse-grained wollastonite fragment as compared with powder wollastonite. The coarse-grained wollastonite fragment-water (acid) reaction resulted in the solution with an elevated constant pH value (alkaline) giving an important significance on the environmental view point.

• Journal of the Mineralogical Society of Korea
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• v.14 no.2
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• pp.85-98
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• 2001

This study deals with the petrographic examination of aggregates(ASTM C 295) which is one of the methods to diagnose the quality of aggregates for concrete artifacts. A number of examinations including size and sieve analysis, test on the coating material, description of the weathering and contamination condition, petrographic description, and qualitative and quantitative analyses on the rocks and minerals potential to alkali-aggregates reactivity are carried out to examine the quality of aggregates. Petrographic description method examined on the fluvial aggregates from Maewhacheon A, B area, Uljin-gun, Kyungnam province shows that weathering grade ranges from F(fresh) to WS(slightly weathered) and coating material and contamination are not in a harmful condition. The weight percentage of the alkali-aggregates reactive minerals or structurally unstable rocks of the aggregates from study area covers 26% and 19% of all aggregates, respectively. So it is necessary to further identify their quality through the chemical(ASTM C 289) and mortar-bar method (ASTM C 227).

• Journal of the Mineralogical Society of Korea
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• v.17 no.2
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• pp.177-187
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• 2004

Measurements of the lattice parameters of albite and oligoclase from electron diffraction patterns with the Au internal standard resulted in errors of less than 1 %. An electron diffraction map for natural oligoclase samples was constructed and 11 stations of zone-axes diffraction patterns were obtained. This process is indispensible for reliable TEM studies of triclinic feldspars. Utilizing the [001] cleavage plane of feldspar and the double-tilting TEM holder the following information is obtainable: Si-Al ordering and chemistry of alkali feldspars could be estimated from the $\alpha$＊ - ＊ plot, where ＊ is measured from the [001] orientation, while $\alpha$＊ is measured from the [100] orientation. Si-Al ordering of Na-rich plagioclase could be estimated from ＊ [001] patterns. Structure and chemistry or Na-poor plagioclase could be estimated from existence of e-reflections, their intensity variations as well as their positional changes.

• Journal of the Mineralogical Society of Korea
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• v.25 no.4
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• pp.249-261
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• 2012

Phlogopite-bearing orthopyroxenite occurs in Andong ultramafic complex in a planar body of about 1 meter thick, and consists mostly of coarse subhedral to euhedral orthopyroxene crystals. Minor minerals are clinopyroxene, phlogopite, and plagioclase with trace chromian spinel, pentlandite, apatite, and zircon. Clinopyroxene occurs as either exolution lamella or interstitial fillings with phlogopite and plagioclase. Electron microprobe analysis showed that orthopyroxenes are entatite, while clinopyroxenes are diopside with little chemical variation through samples. Hydrous alteration resulted in the formation of talc, amphibole, and serpentine from orthopyroxene, clinopyroxene, and plagioclase, respectively. The orthopyroxenite was probably formed by the fractional crystallization of the ultramafic magma. Radiogenic dating of phlogopite and zircon of the orthopyroxenite would reveal the age of the Andong ultramafic complex.

• Journal of the Mineralogical Society of Korea
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• v.22 no.2
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• pp.87-95
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• 2009

The spectroscopic characteristics of the diffusion of beryllium into sapphire are investigated by UV-Vis and FTIR spectroscopy. The $Be^{2+}$ diffused samples are observed in an immersion filled with methylene iodide. The blue colors were fainteddue tochanges of iron's electrovalence ($Fe^{2+}$${\rightarrow}$$Fe^{3+}$) after heat treatment in an oxidation atmosphere and the pink color appeared due to $Cr^{3+}$ in case of violet sapphire. The blue sapphire containing light brown showed yellow orange color due to reaction of beryllium with trace elements during the beryllium diffusion. From analysis of immersion filled with methylene iodide, we could demonstrate to show yellow orange with concentrated color in the rim of samples. Also, there were some changes to the pre-existed inclusions.

• Economic and Environmental Geology
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• v.15 no.4
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• pp.189-204
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• 1982

The Geodo mine is located in the southern limb of the Hambaeg syncline. Geology of the area consists of Paleozoic-Mesozoic sedimentary Rocks and Cretaceous igneous rocks. The important igneous rocks presumably related to skarnization and ore mineralization in the area, are the early granodiorite and the late porphyritic granodiorite. Two mineralogical types of ore deposits are recognized in the area. They are the Fe-Cu deposits in the Myobong formation and the Au-Bi-Cu deposits in the Hwajeol formation. Contact metamorphism due to granodiorite intrusion includes hornfelsization, exoskarnization and endoskarnization. Wall-rock alterations related to the Fe mineralization are grouped into the hydrothermal replacement skarnization and the hydrothermal filling skarnization. Another hydrothermal alteration is associated with the Cu mineralization. Various mineralogical analyses have been applied for the identification of minerals. They include optical microscopy, chemical analysis, etching test, X-ray diffraction, and infrared absorption spectroscopic analyses. The ore minerals in these ore deposits are classified into two groups;hypogene and supergene minerals. Hypogene minerals consist of magnetite, pyrite, chalcopyrite, and chalcocite. Supergene minerals consist of chalcocite, bornite, and geothite. Ore minerals show various kinds of ore texture: open-space filling, exsolution, replacement, and cementation texture. The gangue minerals consist of quartz, diopside, epidote, garnet and plagioclase in the hornfelsic zone, garnet, diopside, scapolite, actinolite, sericite, chlorite, quartz, and calcite in the skarn zone, and, epidote, chlorite, sericite, quartz, and calcite in the late hydrothermal alteration zone. This study shows that the Fe-Cu deposits are of metasomatic pipe type with the later hydrothermal fillings, and the Au-Bi-Cu deposits are of hydrothermal fissure-filling type. The mineralization is probably related to the intrusion of porphyritic granite.