• Mineral and Industry
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• v.18 no.1
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• pp.1-17
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• 2005

국내의 납석 광상은 대부분 백악기의 화산암류들이 열수변질되어 형성된 광상으로서, 주로 전남 및 경남 지역에 밀집되어 분포한다. 납석은 지질 여건상 주로 경상분지 내에 국제적인 규모의 풍부한 부존자원이 있지만, 그 동안의 개발에 의해서 고품위 황석들은 상당히 채진된 상황이다. 현재 개발되고 있는 광체들은 몇 곳의 광산을 제외하고는 대부분 저품위 광상을 이루고 있기 때문에, 새로운 광체의 탐광이 이루어지지 않는다면 앞으로 고품위 광석에 관한 한 국내의 수요를 충당하기 어려운 상황에 이를 것으로 예견된다. 현재 국내에서 납석으로 개발되고 있는 광석의 상당수(대략 $40\%$ 정도)가 엄밀한 의미에서는 사실상 납석이 아닌 고령토나 견운모 광석인 것으로 밝혀졌다. 엽납석을 함유하는 정상적인 형태의 납석들은 그수반 점토광물상에 의거하여 (l) 엽납석질, (2) 딕카이트질. (3) 일라이트질 및 (4) 딕카이트-일라이트질 유형으로 구분될 수 있다. 고령토 광물로는 대부분 딕카이트가 수반되고 외국에서는 흔히 수반되는 것으로 알려져 있는 고령석은 거의 함유되지 않는 것이 특징이다. 석영은 납석에서 점토광물 못지않게 그 용도를 가름하는 주요 성분으로서 대부분의 광석 유형에서 수반되지만 특히 일라이트질 납석에서 흔히 그리고 보다 많이 수반되는 양상을 보인다. X-선회절 정랑분석법은 납석의 품위를 산정하는데 유력한 수단이 될 수 있다. 특히 납석 이외의 점토광물들의 조성, 특히 일라이트의 함유 정도는 납석의 용도별 품위와 품질을 가름하는 주요 사항이다. 화학분석에 의한 납석의 평가 방식은 특히 납석의 백색 도기류와 같은 각종 세라믹스 제조 용도에서의 품질 평가에 결정적인 단서를 제공하는 유력한 평가수단이다. 특히 착색유발 성분인 철분의 존재와 그 함량을 정하고 요업용도에서 중요한 $Al_3O_3$와 알칼리 성분 함량을 검증하는데 필수적인 평가 방법이다. 이외에 주사전자현미경 관찰을 통해서 납석의 주요 품질 기준이 되는 극미립상 엽납석의 결정형, 조직 및 미시적 산출상태를 보다 정밀하게 평가할 수 있는 방안을 제공한다. 현행 광업법상의 납석을 비롯한 관련 광종들의 광물분류 체계가 모호하게 설정되어 있고 관련 인허가 부서에서의 전문성 및 지도력 부족으로 관련 산업계에 심각한 비효율성과 오류가 야기되고 있는 실정이다. 이를 개선하기 위해서는 납석의 광석평가 방식이 그 품위와 품질 개념 하에서 응용광물학적으로 적용되어야 할 것이다.

• Journal of the Mineralogical Society of Korea
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• v.22 no.4
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• pp.331-342
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• 2009

Groundwater samples were collected from the bedrock aquifers related with Okcheon metasedimentary rocks. Arsenic (As) concentrations in the samples varied between 0.0051 and 0.887 mg/L, with an average of 0.0248. Cations and anions of groundwaters had no relationship with As contents as well as with spatial distribution of geology in the area. Pyrite, chalcopyrite and arsenopyrite in the core samples of the monitoring wells were identified in thin section, X-ray diffraction (XRD) and electron probe microscope analysis (EPMA). It was suggested that these minerals are responsible for the As in groundwater. The groundwater showed saturations with respect to calcite $(CaCO_3)$, dolomite (CaMg$(CO_3)_2$) and Magnesite $(MgCO_3)$. $HAsO_4{^{2-}}$ activities in the groundwater samples were close to $Ca_3(AsO_4)_2(c)$ and $Mn_3(AsO_4)_2(c)$ solubility isotherms, indicating that the maximum As contents in groundwater are secondly controlled by the precipitation and dissolution of carbonate minerals due to alkaline and oxic nature of the groundwater (pe+pH>10).

• 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.23 no.2
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• pp.171-183
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• 2010

• Economic and Environmental Geology
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• v.45 no.2
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• pp.189-194
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• 2012

The consequences of microbe-mineral interaction often resulted in the chemical, structural modification, or both in the biologically induced mineral. It is inevitable to utilize the high powered resolution of electron microscopy to investigate the mechanism of biogenic mineral transformation at nano-scale. The applications of transmission electron microscopy (TEM) capable of electron energy loss spectroscopy (EELS) to the study of microbe-mineral interaction were demonstrated for two examples: 1) biogenic illite formation associated with structural Fe(III) reduction in nontronite by Fereducing bacteria; 2) siderite phase formation induced by microbial Fe(III) reduction in magnetite. In particular, quantification of the changes in Fe-oxidation state at nanoscale is essential to understand the dynamic modification of minerals resulted from microbial Fe reduction. The procedure of EELS acquisition and advantages of EELS techniques were discussed.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.3
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• pp.168-178
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• 1994

Acid sulfate soils occur extensively in Gimhae area where they have been formed from the brackish alluvial sediments along the sea coast and river estuary. The strong acid environment enhances silicate weathering and thus affects the soil clay minerals. The minerals were identified through chemical, X-ray diffraction and thermal methods. The ratio of $SiO_2$ and $Al_2O_3$ in the clay fractions ranged from 3.14 to 3.77, indicating that the distribution of the clay minerals were 1 : 1 and 2 : 1 minerals. Cation exchange capacity in the clay fractions was low due to high contents of 1 : 1 minerals and hydroxy interlayered vermiculite(HIV). The B and C horizon rich in jarosite have large amounts of yellow streaks which reflect high content of $Fe_2O_3$ and $K_2O$. Vermiculite and illite were quantified from thermogravimetry(TG), kaolin minerals from both TG and differential thermal analysis(DTA), and HIV from X-ray diffraction analysis. The dominant clay minerals were kaolin minerals, vermiculite, illite and HIV. HIV considered to be formed, especially, in acid soil environments. The minor minerals were quarts, feldspar, jarosite, pyrite, hematite and goethite. Kaolin minerals were the most abundant clay minerals throughout the acid sulfate soil. Kaolin minerals, however, increased towards the top of horizons throughout the soils and HIV decreased towards the top of horizons in the soil of Gimhae series and Haecheog series. Alteration of HIV to kaolin minerals during weathering of low pH condition in deep soil horizons may explain the high quantities of kaolin minerals and the relatively low quantities of HIV in the soil at top horizons.

• Economic and Environmental Geology
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• v.41 no.1
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• pp.151-163
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• 2008

Since the country's opening to the world, China's rapid economic growth has resulted in strong demand for a wide variety of mineral commodities. During the same period, China's mineral production increased sharply. China's increased mineral production and demand affected the worldwide availability of minerals and metals, the market prices, and trade. Ministry of Land and Resources of China (MLR) planned to build as many as 10 strategic mineral reserve, including reserves of aluminium, copper, manganese, uranium, and other mineral that the country urgently needed. In white paper of China's mineral resources, China is planning the mineral resources conservation and its reasonable utilization, domestic supply increase of resources, activation of cooperative development with foreign partners, balance in resources development and environment conservation, and sustainable resources management as the mineral resources policies for the China's economic development.

• Economic and Environmental Geology
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• v.44 no.3
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• pp.203-215
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• 2011

Geochemical and mineralogical properties of a contamited soil should be taken into account to decide a remediation strategy for a given contaminant because development and optimization of soil remedial technologies are based on geochemical and mineralogical separation techniques. The objective of this study was to investigate the geochemical and mineralogical characteristics of arsenic-contaminated soils. The arsenic-contaminated soil samples were obtained from Chonam gold mine, Gwangyang, Chonnam, Particle size analysis, sequential extraction, and mineralogical analyses were used to characterize geochemical and mineralogical characteristics of the As-contaminated soils. Particle size analyses of the As-contaminated soils showed the soils contained 17-36% sand, 25-54% silt, 9-28% clay and the soil texture were sandy loam, loam, and silt loam. The soil pH ranged from 4.5 to 6.6. The amount of arsenic concentrations from the sequential soil leaching is mainly associated with iron oxides (1 to 75%) and residuals (12 to 91%). Major minerals of sand and silt fractions in the soils were feldspar, kaolinite, mica, and quartz and minor mineral of which is an iron oxide. Major minerals of clay fraction were composed of illite, kaolinite, quartz, and vermiculite. And minor minerals are iron oxide and rutile. The geochemical and mineralogical analyses indicated the arsenic is adsorbed or coprecipitated with iron oxides or phyllosilicate minerals. The results may provide understanding of geochemical and mineralogical characteristics for the site remediation of arsenic-contaminated soils.

• Journal of the Korean Geotechnical Society
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• v.20 no.9
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• pp.155-166
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• 2004

The characteristics of soft clays are very important for the land development plan. This study is to investigate correlations between the engineering properties and the characteristics of clay minerals of the undisturbed clay samples obtained from Sihwa area. This study included X-Ray diffraction analysis, X-Ray fluorescence spectrometer analysis, scanning electron microscopy analysis and energy dispersive X-Ray spectrometer analysis. The correlations between the clay mineral properties and the laboratory and field testing results were investigated. The characteristics of soft clay in Sihwa area were compared with those in Yangsan and Kunsan area.

• Mineral and Industry
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• v.21 no.1
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• pp.39-47
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• 2008