• Economic and Environmental Geology
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• v.28 no.1
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• pp.9-17
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• 1995

The Kamkye Cu-Pb-Zn-Au-Ag deposits occur as quartz veins that filled fault-related fractures of NW system developed in the Cretaceous Gyeongsang basin. Three major stages of mineral deposition are recognized: (1) the stage I associated with wall rock alteration, such as sericite, chlorite, epidote and pyrite, (2) the early stage II of base-metal mineralization such as pyrite, hematite, and small amounts of sphalerite and chalcopyrite. and the middle to late stage II of Cu-As-Sb-Au-Ag-S mineralization, such as sphalerite, chalcopyrite, galena with tetrahedrite, tennantite, pearceite, Pb-Bi-Cu-S system, argentite and electrum. (3) the stage III of supergene mineralization, such as covellite, chalcocite and malachite. K-Ar dating of alteration sericite is a late Cretaceous ($74.0{\pm}1.6Ma$) and it may be associated with granitic activity of nearby biotite granite and quartz porphyry. Fluid inclusion data suggest a complex history of boiling, cooling and dilution of ore fluids. Stage II mineralization occurred at temperatures between 370 to $220^{\circ}C$ from fluids with salinities of 8.4 to 0.9 wt.% NaCl. Early stage II($320^{\circ}C$, 2.0 wt.% NaCl) may be boiled due to repeated fracturing which opened up the hydrothermal system to the land surface, and which resulted in a base-metal sulfide. Whilst the fractures were opened to the surface, mixing of middle-late stage II ore fluids with meteoric waters resulted in deposition of Cu-As-Sb-Au-Ag minerals from low temperature fluids(${\leq}290^{\circ}C$). Boiling of ore fluids may be occured at a pressure of 112 bar and a depth of 412 m. Equilibrium thermodynamic interpretation of sphalerite-tetraherite assemblages in middle stage II indicates that the ore-forming fluid had log fugacities of $S_2$ of -6.6~-9.4 atm.

• Economic and Environmental Geology
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• v.28 no.1
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• pp.43-51
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• 1995

The Jangsan Quartzite is a basal unit of the Cambro-Odovician sequence, in Socheon-Myeon, Bonghwa-Gun, Gyeongsangbug-Do, South Korea, was petrologically and geochemically investigated. The quartzite consists mainly of quartz and muscovite, assosiated with tourmaline and graphite. The quartzite shows white and/or gray color and various green color in hand specimens. The white and gray colored rocks have very low vanadium contents, but a dark green colored rock contains 8960 ppm vanadium. The muscovites in the quartzite show colorless and green color, of which green ones range from pale blue green to pale green. The dark green colored muscovites have above 8 wt. % vanadium and pale green ones have 1-3 wt. % vanadium. Vanadium contents in moscovite increase with decreasing $Al^{v1}$ contents. It suggests that vanadium substitutes for octahedral aluminium in moscovite. In general, it tends to large volumes of muscovite (up to 14 modal %) in deep green colored rocks, and high vanadium contents in their muscovites. Most of the moscovite flakes occur along the quartz boundaries and some are enclosed by quartz grain. The moscovite grains intergrowth each other in the former. The mouscovite aggragates are divided into two types on the basis of their intergrowth(cut) times. Two cut times and one cut time are named T type and D type, respectively. The T type is mainly distributed at western part (near of the Chunyang granite), whereas the D type is distributed from middle to estern part(near the Janggunbong) of the formation. The boundary is consistent with metamorphic isograd between andalusite and sillimanite zone by Ahn et. al. (1993).

• Economic and Environmental Geology
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• v.40 no.4
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• pp.375-387
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• 2007

The Iksan Mireuksaji stone pagoda, designated as national treasure No. 11 in Korea, has been in the process of disassembling for reconstruction as part of the cultural heritage conservation program. The pagoda is mainly consisting of granite, which is relatively resistant to weathering. However, it has lost its original rock color due to various contaminants deposited at the surface since it exposed to the atmospheric environment long time. In this research, we categorized the secondary inorganic contaminants into the genetic type, and also quantitatively examined occurrences and types of pollutants in the oxidation area of the pagoda surface in which the area is clearly distinguished by naked eyes. Geochemical behavior of soluble pollutants through reaction experiments are demonstrated, and effective methods of cleaning for the conservation and scientific applicability of the surface cleaner are also studied.

• Tunnel and Underground Space
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• v.10 no.2
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• pp.165-172
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• 2000

When tunnels or underground structures are constructed in anisotropic rock mass, designers and constructors have to consider the anisotropic characteristics in rock mass because their physical and mechanical properties are depended on the anisotropic angles(${\beta}$). In this study, therefore, we have first investigated the mechanical behavior of the gneiss specimen from lab. tests, and then have analysed the behavior of specimens for to the transversely isotropic model in elastic medium using the FLAC program. The results of this study were summarized as follows; 1) In the result of the variation tests, in general, the properties of strength were depended on the angle of inclination in spite of the hard rock. And except for the shear strength test, the lowest and peak stress were appeared at 60$^{\circ}$ and 90$^{\circ}$respectively. 2) The results of specimen modeling analysis using FDM well indicated the mechanical behaviors of the specimen of transversely isotropic model.

• Journal of environmental and Sanitary engineering
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• v.20 no.1 s.55
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• pp.55-63
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• 2005

Ground water samples of 275 were collected from Gapyeong county which it contained six-eup and myeon and analyzed for 12 mineral inorganics extending from March to October in 2004. Among the inorganics, Calcium, Magnesium, Sodium, Potassium, Copper and Zinc had more than $70\%$ of detection frequencies, which coincided with essential inorganics required by the human body. The average values of inorganic contents by sampling sites were insignificant. Fluorine contents of 8 samples, $2.9\%$ of 275 samples, exceeded KDWR, and it was considered to be affected by a base rock being made up granite and gneiss because there were not polluting sources around. It is necessary to find out relation between geological characteristics and mineral inorganics in ground water through the further investigation. Compared to noted concentrations of bottled water, inorganic minerals including Calcium, magnesium, Sodium and Potassium related to taste were fluent double in target samples and those average concentrations were 14.80, 3.80, 7.60, and $2.31\cal{mg/L}$ respectively.

• Journal of Conservation Science
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• v.26 no.3
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• pp.325-334
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• 2010

In order to clarify the effect of consolidant, the artificial porous material with low intensity was manufactured using granite powder and Portland cement. We have prepared four kinds of alkoxysilane system consolidants, a acrylic resin and a epoxy resin and investigated about characteristics before and after consolidation. As a result of the research, Silres BS OH 100 was effective for density and surface hardness. SS-101 with hydrophobicity and Site SX-RO with hydrophilicity had the good durability over salts weathering. On the other hand, Syton HT-50 and Paraloid B72 were easily destructed by salt weathering because they were concentrated on surface area by the low penetration depth. Araldite 2020 was the most effective consolidant for improvement of physical properties.

• Explosives and Blasting
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• v.23 no.4
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• pp.1-18
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• 2005

The underground research tunnel, which is under construction in KAERI for the validation of HLW disposal system, is excavated in a granite rock by drill&blasting. In order not to disturb the operation at the research facilities including Hanara reactor by the blasting for the excavation of $6m{\times}6m$ tunnel, a test blasting at the site was performed. Using the vibration equation derived from the test blasting, it was possible to predict the vibration at different locations at KAERI and to conclude that the blasting design would meet the design criteria at the major facilities in KAERI. The noise and vibration generated by the main blasting were continuously measured. In the case of vibration, the measured values were lower than the predicted one from the vibration equation. It is, therefore, concluded that the influence of blasting work for the construction of 280m long research tunnel on the major facilities in KAERIl would be insignificant.

• Nuclear Engineering and Technology
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• v.28 no.4
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• pp.349-358
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• 1996

The leaching behavior of uranium from unirradiated CANDU UO$_2$ fuel pellet in the spent fuel wet storage and disposal conditions has been investigated. A modified IAEA leach test method was used, and then the extent of leaching was monitored by analysis for uranium in the leachant. The leach test has been performed in various leachants(demineralized water and boric acid solution at pH=6, synthetic granite groundwater) for a long-term period of 5.4 years, and the effect of temperature on the leach rate of uranium has been analyzed. The leach rates of uranium at $25^{\circ}C$ were dependent on the leachants. Over initial 100 days of leach periods, the leach rate in groundwater was the highest in three leachants and no significant differences of leach rates ore observed in the demineralized oater and boric acid solution. But these leach rates in three leachants around 2,000 days at $25^{\circ}C$ appeared to be reached the steady rates in the range of 1~5$\times$10$^{-8}$ g/$\textrm{cm}^2$ day. The leach rate of uranium in groundwater shooed to be independent of the temperature, but those in both demineralized water and boric acid solution increased with temperature. These results show that the leaching behavior of uranium from UO$_2$ fuel in both the demineralized water ann boric acid may be controlled tv the surface oxidative.dissolution reaction of UO$_2$ and the leach rate of uranium in groundwater at room temperature could mainly be controlled by the complex reaction of dissolved uranyl ions with carbonate ions and no variation of leach rate of UO$_2$ in groundwater with temperature may be due to the local deposition of passivating uranyl phases on the surface.

• Journal of Environmental Science International
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• v.27 no.8
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• pp.651-663
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• 2018

The hydrochemistry of groundwater from 47 wells in the Chungwon area, Korea was analyzed to examine the occurrence of natural radionuclides like uranium and radon. The range of Electrical Conductivity (EC) value in the study area was $67{\sim}1,404{\mu}S/cm$. In addition to the high EC value, the content of cations and anions also tends to increase. Uranium concentrations ranged from $ND{\sim}178{\mu}g/L$ (median value, $0.8{\mu}g/L$) and radon concentrations ranged from 80~12,900 pCi/L (median value, 1,250 pCi/L). Uranium concentrations in one well, that is 2.8% of the samples, exceeded $30{\mu}g/L$, which is the Maximum Contaminant Level (MCL) proposed by the US Environmental Protection Agency (EPA), based on the chemical toxicity of uranium. Radon concentrations in three wells, that is 6% of the samples, and one well, that is 2.8% of the samples, exceeded 4,000 pCi/L (AMCL of the US EPA) and 8,100 pCi/L (Finland's guideline level), respectively. Concentrations of uranium and radon related to geology of the study area show the highest values in the groundwater of the granite area. The uranium and radon contents in the groundwater were found to be low compared to those of other countries with similar geological settings. It is likely that the measured value was lower than the actual content due to the inflow of shallow groundwater by the lack of casing and grouting.

• Tunnel and Underground Space
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• v.13 no.1
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• pp.64-75
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• 2003

This study presents a newly suggested test method of Mode II fracture toughness measurement called "Punch Through Shear Test" which was originally proposed by Backers and Stephansson in 2001. The purpose of this study is to check the validity of the suggested testing method by performing Mode II fracture toughness tests for Daejeon Granite. In addition, the optimal specimen geometry for the testing and the relation between Mode II fracture toughness and confining pressure were also investigated. Fractured surface was observed to be very smooth with lots of rock debris which came off fracture surface which obviously implies that the surface was sheared off. This confirms that Mode II fracturing actually occurred. In addition, numerical analyses including continuum analysis, particle flow code analysis and crack propagation simulations were performed. Results of these numerical analyses indicated that the cracks occurred in the specimen were predominantly in Mode II and these cracks led to failure of the test specimen. From this investigation, it can be concluded that the newly suggested "Punch Through Shear Test" method provides a reliable means of determining the Mode II fracture toughness. fracture toughness.