• Mineral and Industry
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• v.26
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• pp.13-21
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• 2013

This study is carried out experiments on various factors for improving the grade of low grade scheelite by Knelson concentrator prior to the main beneficiation process. Even though there are several gravity separators such as Jig, Spirals and etc. for rougher concentrate, the KC3 Knelson Concentrator was adopted to get better separation efficiency and beneficiating effects for pre-concentration of the low grade scheelite ore. The feed samples was prepared to minus 1mm in size by crushing and grinding. The important factors in the KC3 Knelson Concentrator test were examined in terms of the variations such as number of treatment, feed rate, rotation speed of bowl(G force), water flow rate, pre-removal of magnetic minerals, feed size and feed grade. According to the result of experiment, it shows that the important technical variations are limited in terms of number of treatment, feed rate, feed size and feed grade. The final result shows that the KC3 Knelson Concentrator obtains the scheelite pre-concentrate of about $3%WO_3$ grade and 90% recovery, respectively, from the feed containing about $0.8-1.0%WO_3$ grade.

• Journal of Conservation Science
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• v.32 no.2
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• pp.123-139
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• 2016

The excavated potteries of Goryeo Period from the Sandongri archaeological site in Seosan were studied on physicochemical analyses. Surface color of the samples are mainly grayish blue, and showed the natural glaze by melting the body soils during the burning. Partly, swelling surface are observed bloated marks because of blow out gas by burning. The potteries are some possibility of making the similar source clay on the basis of magnetic susceptibilities (about $1{\times}10^{-3}SI\;unit$) and general occurrences. Values of specific gravity, apparent porosity and absorption ratio are divided two groups as highly different cases of bloating surface samples. The source clay of the potteries used mainly microcrystalline clay, the mineral compositions are quartz and some colored minerals. Based on the analysis, the burning temperature of the potteries are assumed that they were around $1,100^{\circ}C$ because detection of quartz and mullite within hard and compact matrices. As geochemical variations of the samples, evolution trends of rare earth, compatible and incompatible elements showed very similar patterns excepting the some major elements, that means the potteries are interpreted to making by elutriation processes using the same raw clays from very similar basement rocks of genetically.

• Journal of Conservation Science
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• v.26 no.1
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• pp.1-12
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• 2010

The crucibles of Baekje Kingdom from the Ssangbukri Site which were used for glass and metal melting had light brown, grayish blue and grayish brown colored bodies. In thin section, the crucibles contained numerous quartz grains and pottery fragments. The surface was covered with fine grained quartz for thermal resistance. Based on decomposition of mica group minerals and formation of mullite detected by X-ray diffraction analysis, it was inferred that all crucibles have been fired over $1,000^{\circ}C$. It was also found that firing temperature has exceeded $1,100^{\circ}C$ in some crucibles because feldspar was not detected. The maximum temperature was assumed at $1,200^{\circ}C$. The magnetic susceptibility values and geochemical characteristics sorted out the crucibles into two groups that differed from the characteristics of the local soils. This reflected geological setting of the site where the alluvium was formed from two kinds of surrounding rock masses, granite gneiss and biotite granite. However, the local soils had similarities with the crucibles in weathering degree and geochemical behavior of major elements. In consequence, it was considered that the raw clay of the crucibles was supplied from the local area of the site.

• Journal of Conservation Science
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• v.33 no.4
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• pp.241-254
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• 2017

The Stone Guardian and Memorial Tablets from the Muryeong Royal Tomb are composed of the same kind of plutonic igneous rocks, the so-called hornblendite. Color of the rocks show greenish gray, and both of them occurred with medium-grained granular texture. The rock-forming minerals composed mainly of amphibole and plagioclase. Magnetic susceptibility of the Stone Guardian is 0.15 to 0.63 (mean $0.42{\times}10^{-3}SI\;unit$), the King's Stone Memorial Tablet is 0.11 to 0.38 (mean $0.24{\times}10^{-3}SI\;unit$) and the Queen's Stone Memorial Tablet ranges from 0.10 to 0.33 (mean $0.18{\times}10^{-3}SI\;unit$). The rocks of the artifacts are hard to find in the Gongju area. Large scaled out crop of hornblendite is not distributed, but found in many places that the form of dike. The lithology and occurrences indicate that the artifacts are made of plutonic rock rather than dike. Reddish brown and pale brown contaminants, are also distributed on the surface of the Stone Guardian and Memorial Tablets. The reddish brown color is due to Fe oxide, and the pale brown color occurs due to the elution of Ca. The reddish brown contaminants are influenced by the internal components of the rock and oxidation of burial iron accessories. In contrast, the pale brown contaminants are considered to have flown from the carbonate materials used in the Royal Tomb, with a little added Fe oxide. Physical and chemical deterioration operate intricately in the Stone Guardian and Memorial Tablets. Physical deterioration is extremely rare and chemical deterioration is stable except for a part of the Stone Guardian and the front of the Queen Stone Memorial Tablet.

• The Journal of the Petrological Society of Korea
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• v.27 no.4
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• pp.185-194
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• 2018

The basaltic rocks of Daljeon-ri columnar joint (Natural Monuments # 415) and Noeseongsan Noerok site (Natural Monuments # 547) were analysed in order to understand basalt types of two areas. The basaltic rocks of the Pohang Daljeon-ri columnar joint show a typical porphyritic texture containing phenocrysts (olivine and clinopyroxene) and groundmasses composed of clinopyroxene, plagioclase, and opaque minerals,. In contrast, basaltic rocks of Noeseongsan Noerok are characterized by fine-grained groundmass with large phenocrysts of plagioclase. Other analysis such as magnetic susceptibility, X-ray diffraction and X-ray fluorescence also support the petrological differences of two basalt rocks. The Daljeon-ri basaltic rocks are plotted on phonotephrite volcanic rocks of alkaline series in TAS(total alkali silica), and on within plate basalt in Zr-Ti diagram. The Noeseongsan basalts, on the other hand, are plotted on basaltic andesite to andesite of sub-alkaline series in TAS, and on volcanic arc basalt in Zr-Ti diagram. These results indicate that the original mantle materials between two basalt rocks were different each other, which probably originated from the change of a tectonic setting in the southeastern Korean peninsula during the Miocene.

• Korean Journal of Heritage: History & Science
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• v.45 no.3
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• pp.174-193
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• 2012

This study focused on distribution ratio of stone properties based on material characteristic analysis, provenance presumption and transportation route interpretation of the Sungnyemun stone block foundation. The stone block foundation is composed of pinkish granite (56.0%), reddish granite (4.5%) and leucocratic granite (26.2%) of original stones and pinkish granite of new stones(13.3%). The rock-forming minerals for granites are consisted mainly of quartz, alkali-feldspar, plagioclase and biotite, and are similar geochemical evolution trend of major, rare earth, compatible and incompatible elements. Therefore, it is clear that the rocks are genetically same origin. As a result of magnetic susceptibility measurement, the pinkish and reddish granite of original stones and pinkish granite of new stones showed normal distribution around about 4.00(${\times}10^{-3}SI\;unit$). But the leucocratic granite of original stones were confirmed ilmenite series under about 1.00(${\times}10^{-3}SI\;unit$). As a result of provenance interpretation and transportation route analysis based on the petrological results, the provenance of pinkish granite and reddish granite of original stones are presumed the north slope in Namsan mountain and Naksan mountain. Also, the leucocratic granite of original stones and the pinkish granite of new stones are strongly possible furnished from the south and north slope in Namsan mountain and Naksan mountain, respectively.

• Korean Journal of Heritage: History & Science
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• v.46 no.3
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• pp.48-67
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• 2013

This study was focused on the recognition of historical values and the establishment of conservation schemes for a Silla stone monument in Bongpyeong-ri, Uljin by combining the humanistic investigation of inscription reinterpretation and the scientific conservational diagnosis of deterioration. According to the investigation of inscription, a total of 13 letters were reconsidered compared to the preceding researches. Thus, the meaning and interpretation of previous inscription was partially changed. This monument is composed of gneissose leucogranite and the most suitable site as provenance of the stone would be the Jukbyeon seashore (2.1km). The site shows similar color, size and composition of minerals, gneissose structure and magnetic susceptibility as the Bongpyeong stone monument. This monument developed a structural crack (crack index 0.4) and a microcrack (crack index 2.0) along the gneissose structure. The horizontal strength is weaker than the vertical strength. Therefore, the cracks should be reinforced and treated. However, consolidating is not urgently needed because the total weathering grade by ultrasonic velocity shows the stage of moderate weathering(3,403m/s, 0.32). Also, the major problems of chemical deterioration are blackening (85.2%) with soil, iron oxide,rubbing mark, and salt crystals (17.3%) from the sea. Therefore, the contaminants and the salt crystals should be removed using pressure spray and pulp paper, while the application of poultice should be examined through clinical tests.

• The Journal of the Petrological Society of Korea
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• v.11 no.1
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• pp.1-16
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• 2002

The study area is mostly composed of Precambrian Gyeonggi gneiss complex, Jurassic Daebo granites, Cretaceous tonalite and dykes, and so on. On the basis of field survey and mineral assemblage, the granites can be divided into three types; biotite granite (Gb), garnet biotite granite (Ggb) and two mica granite (Gtm). They predominantly belong to monzo-granites from the modes. Field relationship and K-Ar mica age data in the surrounding area suggest that intrusive sequences are older in order of Gtm, Ggb and Gb. Gb and Ggb, major study targets, occur as medium-coarse grained rocks, and show light grey and light grey-light pink colors, respectively. Mineral constituents are almost similar except for opaque in Gb and garmet in Ggb. Gb and Ggb have felsic, peraluminous, subalkaline and calc alkaline natures. In Harker diagram, both rocks show moderately negative trends of $TiO_2$, MgO, CaO, $Al_2O_3$, $Fe_2O_3$(t), $K_2O$ and $P_2O_5$ as $SiO_2$ contents increase. Among them, $TiO_2$, MgO and CaO show two linear trends. From the trends and the linear patterns in AFM, Sr-Ba and Rb-Ba-Sr relations, it is likely that they were originated from the same granitic magma and Ggb was differentiated later than Gb. REE concentrations normalized to chondrite value have trends of parallel LREE enrichment and HREE depletion. One data of Ggb showing a gradually enriched HREE trend may be caused by garnet accompaniment. Ggb have more negative Eu anomalies than Gb, suggesting that plagioclase fractionation in Ggb have occurred much stronger than that in Gb. In modal (Qz+Af) vs. Op, Gb and Ggb belong to magnetite-series and ilmenite-series, respectively. From the EPMA results, opaques of Gb are magnetite and ilmenite, and those of Ggb are magnetite-free ilmenite or not observed. Bimodal distribution of magnetic susceptibility reveals two different granites of Gb (332.6 ${mu}SI$) and Ggb (2.3 ${mu}SI$). Based on the paleomagnetic analysis as well as modal analysis, the main susceptibilities of Gb and Ggb reside in magnetite and mafic minerals, respectively. They belong to S-type granite of non-magnetic granite by susceptibility value. In addition, $SiO_2$ contents, $K_2O/Na_2O$, A/CNK molar ratio and ACF diagram support that they all belong to S-type granites.

• Journal of the Mineralogical Society of Korea
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• v.31 no.1
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• pp.1-12
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• 2018

A gravity core (RS14-C2) was collected at site RS14-C2 in the continental slope to the east of Pennell-Isellin Bank of the Ross Sea (Antarctica) during PNRA XXIX (Rosslope II Project) Expedition. In order to trace the sediment source, magnetic susceptibility (MS), sand fraction, and clay mineral compositions were analyzed, and AMS $^{14}C$ ages were dated. Core sediments consist mostly of hemipelagic sandy clay or silty clay including ice-rafted debris (IRD). AMS $^{14}C$ age of core-top indicates the modern and Holocene sediments. Based on AMS $^{14}C$ dating, sediment color, MS and sand fraction, core sediments are divided into interglacial and glacial intervals. The interglacial brown sediments are characterized by low MS and sand fraction, whereas the glacial gray sediments are characterized by high MS and sand fraction. Among clay mineral compositions of core sediments, illite is highest (61.8~76.7%), and chlorite (15.7~21.3%), kaolinite (3.6~15.4%), and smectite (0.9~5.1%) are in decreasing order, and these compositions are also divided into the interglacial and glacial/deglacial intervals. During the glacial period, the high content of illite and chlorite indicate sediment supply from the bedrocks of Transantarctic Mountains under the Ross Ice Sheet. In contrast, because of decreasing supply of illite and chlorite by the glacial retreat, smectite and kaolinite contents increased relatively during the interglacial period. During the interglacial period, smectite may be transported additionally by the northeastward flowing surface current from the coast of Victoria Land in the western Ross Sea. Kaolinite may be also supplied to the continental slope by the Antarctic Slope Current from the kaolin-rich metasedimentary rock outcropped on the Edward VII Peninsula.

• The Journal of the Petrological Society of Korea
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• v.3 no.1
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• pp.1-19
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• 1994

We present petrography, mode and chemistry data for Fe-Ti oxide minerals from the Mesozoic granitoids in South Korea. Magnetites from the Daebo Uurassic) granites are nearly pure $Fe_3O_4$, while those from the Bulgugsa (Cretaceous) granites contain considerable amounts of Mn and Ti. This is probably related to rapid cooling of the Bulgugsa granites compared with slow cooling of Daebo granites, which is supported by geologic relations and hornblende geobarometry results of Cho and Kwon (1994) on the emplacement depth for these granites. The composition of ilmenite does not shew appreciable difference between the Daebo and Bulgugsa granites. However, $Fe_2O_3$ contents are higher for the ilmenites coexisting with magnetite than for those without magnetite. In the temperature vs. oxygen fugacity diagram, the Bulgugsa granites plot near Ni-NiO and QFM buffer curves, although only two samples show greater than the granite solidus temperature. The mode data suggest that both magnetite- and ilmenite-series exist in Daebo and Bulgusa granites from the Kyonggi massif, Ogcheon belt and Youngnam massif, while only magnetite-series exists in Bulgugsa granites from the Kyongsang basin. Many ilmenite-series granites occur in the Ogcheon belt, which might be related to assimilation of carboniferous sediments in the belt. The proportion (44 : 56) between ilmenite- and magnetite-series for the Daebo granites is significantly different from that of Ishihara et al. (1981) who showed, using magnetic susceptibility data, predominance of ilmenite-series (more than 70%) for the Daebo granites, which can be mainly attributed to preference in sampling and to wrong assignment of age for some plutons. We also found magnetite in weakly-magnetized Kanghwa granite which was formerly classified as ilmenite-series by Ishihara et al. (1981). The proportion of ilmenite-series increases in the order of hornblende biotite granite, biotite granite and two mica granite. We conclude from these observations that the ilmeniteseries granites might have originated from contamination of carboniferous crustal material and/or such source material.