• Proceedings of the Korean Environmental Sciences Society Conference
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• 1999.04a
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• pp.298-301
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• 1999

• Economic and Environmental Geology
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• v.12 no.3
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• pp.127-146
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• 1979

Though tungsten minerals have been mined for over fifty years in Korea, which has become one of the worlds largest tungsten producers since 1951, knowledge of their mineralogy and geochemistry is somewhat limited to the school of tungsten students. There is a considerable amount of literature throughout the world on the tungsten mineralogy, the geochemical behaviour of tungsten, the nature of tungsten deposits and geological environments for tungsten mineralisation. Commonly known tungsten minerals such as scheelite and wolframite belong to one of two series, the scheelite or the wolframite series, as the primary tungsten minerals. Secondary tungsten minerals are known rather rare, however, some of them plays an important role-of exploration guide in search for tungsten deposits. The geochemistry of tungsten is imperfectly known, and apparently the behaviour of tungsten in geological processes has been the subject of few studies. Recently, some aspects of the fundamental geochemistry of tungsten has been worked out and compiled the data in broad the up to date by many authors. In order to facilitate the better understanding and future exploration of tungsten deposits, an attempt has been made to summarise the existing knowledge of the fundamental geochemistry of tungsten, together with its common geochemical association with various types of tungsten deposits.

• Journal of the Mineralogical Society of Korea
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• v.16 no.2
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• pp.151-159
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• 2003

$^{31}$ /P NMR and XRD have been used to study the mineralogical compositions and the phosphorus species in marine sediments near Wolsung nuclear power plant. The core samples with 30cm depth were investigated and no mineralogical changes have been found. The studied marine sediments were composed of quartz, albite, microcline, calcite, and some clay minerals such as illite, smectite, chlorite, and kaolinite. Only orthophosphate-monoester and very small amount of ortho-phosphate-diester were identified as phosphorus species in the studied sample, different from the species reported in other countries. These phosphorus species are mainly from organisms and was exposed to the oxic conditions. The consistent mineralogical compositions as well as the same phosphorus species throughout the entire core samples indicate that the constant oxic condition was kept without any changes in sedimentary conditions or the sediments were deposited with different sedimentary conditions, but later they were disturbed by other activities and exposed to the surface oxic conditions continuously.

• Journal of the Mineralogical Society of Korea
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• v.32 no.1
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• pp.63-69
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• 2019

The oxidation states of structural Fe in minerals reflect the paleo-depositional redox conditions for the biologically or abiotically induced mineral formation. Particularly, nano-scale analysis using high-resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS) is necessary to identify evidence for the microbial role in the biomineralization. HRTEM-EELS analysis of oxidation states of structural Fe and carbon bonding structure differentiate biological factors in mineralization by mapping the distribution of Fe(II)/Fe(III) and source of organic C. HRTEM-EELS technique provides geomicrobiologists with the direct nano-scale evidence of microbe-mineral interaction.

• Journal of the Mineralogical Society of Korea
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• v.22 no.4
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• pp.359-370
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• 2009

Arsenic and heavy metals leached out as a result of oxidation of tailings exposed to the surface pose a serious environmental contamination of mine areas. This study investigated how arsenic behavior is controlled by a variety of processes, such as oxidation of sulfides and formation or alteration of secondary minerals, based on mineralogical methods. The study was carried out using the tailing samples obtained from Nakdong mine located in Jeongseongun, Gangwondo. After separating magnetic and non-magnetic minerals using pretreated tailing samples, each mineral sample was classified according to their colors and metallic lusters observed by the stereoscopic microscope. Subsequently, the mineralogical properties were determined using various instrumental analyses, such as x-ray diffractometer (XRD), energy dispersive spectroscopy (EDS), and electron probe micro analyzer (EPMA). The literature review confirmed that various ore minerals were identified in the Nakdong ore deposits. In this study, however, there were observed a few original ore minerals as well as secondary and/or tertiary minerals newly formed as a result of weathering including oxidation. In particular, we did not recognize pyrrhotite which has been known to originally exist in a large abundance, but peculiarly colloform-type iron (oxy)hydroxides were identified, which indicates most of pyrrhotite has been altered by rapid weathering due to its large reactivity. In addition, a secondary scorodites filling the fissure of weathered primary arsenopyrites were identified, and it is speculated that arsenic is immobilized through such a alteration reaction. Also, we observed tertiary iron (oxy)hydroxides were formed as a result of re-alteration of secondary jarosites, and it suggests that the environment of tailing has been changed to high pH from low pH condition which was initiated and developed by oxidation reactions of diverse primary ore minerals. The environmental change is mainly attributed to interactions between secondary minerals and parental rocks around the mine. As a result, not only was the stability of secondary minerals declined, but tertiary minerals were newly formed. As such a process goes through, arsenic which was immobilized is likely to re-dissolve and disperse into surrounding environments.

• Journal of the Mineralogical Society of Korea
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• v.13 no.3
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• pp.121-137
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• 2000

Weathering profiles which were developed under a temperate, humid environment and relatively steep geography, show a thick saprolite and soil horiaon in the Precambrian granitic gneiss of the Yoogoo area. In the weathering profiles, secondary minerals such as interstratified biotite/vermiculite, tri- or di-octahedral vermiculite, halloysite, kaolinite, illite, smectite, gibsite and geothite were observed. Kaolinization of biotite is the most prevalent mechanism but vermiculitization is a minor from all ofweathering profiles. Biotite altered to B/V mixed layer-vermiculite, to illite and to halloysite, kaolinite and gibbsite. Halloysite is the most frequently observed weathering product of biotite in these profiles. Goethite is observed at the around or opened fissures of altered biotite. Tubular halloysite aggregates was fDrmed from dissolution-precipitation of plagioclase. The occurrence of halloysite aggregates is divided into a preferentially oriented type and a wrinkled one which were resulted from the dissolved type of plagioclase. Fe-bearing minerals have also been subjected to dissolution leaving the precipitation of geothite along dissolution voids. The profile of granitic gneiss is a typical weathering pattern showing a clay minerals increase toward the surface. Weathering of minerals were controlled by locally acidic and good-drainage environment, and formed a various and complicated secondary minerals in this study area.

• Journal of the Mineralogical Society of Korea
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• v.29 no.2
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• pp.73-78
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• 2016

The oxidation states of structural Fe in clay minerals often reflect the paleo-redox conditions of the depositional environments. It is inevitable to utilize the high resolution of transmission electron microscopy (TEM) to investigate the mechanism of mineral transformation at nano-scale. The applications of TEM- electron energy loss spectroscopy (EELS) for quantification of $Fe(III)/{\Sigma}Fe$ from the K-nontronite formation associated with structural Fe(III) reduction in nontronite under deep subseafloor environment were demonstrated. In particular, quantification of the changes in Fe-oxidation state at nanoscale is essential to understand the mechanisms of minerals formation. The procedure of EELS acquisition, quantitative determination of Fe-oxidation states, and advantages of EELS techniques were discussed.

• Journal of the Mineralogical Society of Korea
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• v.13 no.2
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• pp.65-72
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• 2000

미생물을 이용한 광물 합성은 현재 초기 연구단계에 있으나 신소재 개발측면에서 다야한 활용성을 보인다. 본 연구의 목적은 철환원 박테리아를 이용한 자철석 합성에 있어 미치는 환경조건들을 알아보는데 있다. 본 연구를 위해 지하 3-km 코아 시료에서 분리한 호열성 철 환원 박테리아인 TOR-39을 이용하였다. TOR-39은 $65^{\circ}C$에서 12시간이내에 비정질 철수화물을 환원시켜 자철석을 형성한다. 25일 동안 배양하여 형성된 자철석은 정육각형 모양으로 입자 크기는 50-100 나노미터이다. TOR-39을 이용한 자철석 합성시 적절한 조건은 pH는 7.9-8.5, Eh는 -200 mV 이하, 배양기간은 3-25일 그리고 온도는 $45-75^{\circ}C$이다. 미생물에 의한 자철석 합성은 나노미터 크기의 광물을 직접 합성하므로, 산업적으로 많은 이용 가치를 가질 것으로 본다.

• Journal of the Mineralogical Society of Korea
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• v.28 no.2
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• pp.83-93
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• 2015

This study investigated genetic, mineralogical and spectral characteristics of oil shale and coal samples in Dundgobi area, Mongolia. Based the Rock/Eval and Total organic carbon (TOC) analysis, kerogen type, hydrogen quantity, thermal maturity and depositional environment were confirmed. Moreover, the mineral composition of oil shale and coal samples were analyzed by XRD and spectroscopy. The result of Rock Eval/TOC analysis revealed that the samples of Eedemt deposit are immature to mature source rocks with sufficient hydrocarbon potential, and the kerogen types were classified as Type I, Type II and Type III kerogen. On the other hand, the samples from Shine Us Khudag deposit were mature with good to very good hydrocarbon potential rocks where kengen types are defined as Type I, Type II/III and Type III kerogen. According to the carbon and sulfur contents, the depositional environment of the both sites were defined as a freshwater depositional environment. The XRD analysis revealed that the mineral composition of oil shale and coal samples were quartz, calcite, dolomite, illite, kaolinite, montmorillonite, anorthoclase, albite, microcline, orthoclase and analcime. The absorption features of oil shale samples were at 1412 nm and 1907 nm by clay minerals and water, 2206 nm by clay minerals of kaolinite and montmorillonite and 2306 nm by dolomite. It is considered that spectral characteristics on organic matter content test must be tested for oil shale exploration using remote sensing techniques.

• 한국해양학회지
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• v.22 no.3
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• pp.168-178
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• 1987

A study on the mineralogy and internal features have been carried out on a sample of ferromanganese crust from a Central Pacific seamout. The distribution of manganese mineral vernadite($\delta$-MnO$\sub$2/)in the different layers indicates typical hydrogenous origin under a continuous change of growth conditions during crustal firmation. Various internal structures are discerned within the crust which may be attributed to different growth conditions. The growth structure changes and the distinct break in the formation of the crust at about 2 depth are assumed to be the results of Miocene to mid-Pleistocene global palaeoceanographic events.