• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5551-5557
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• 2012

Sedimentary rocks dug up in construction fields are mostly stockpiled for landfill disposal, leading to an increase in construction costs and construction inefficiency. After screening, some of the sandstone can be used as aggregate; however, most of the shale ends up as industrial waste in practice. In this study, to stabilize the demand and develop resources for alternative aggregates of concrete, the potential use of shale, which is widely distributed in the Daegu-Kyeongbuk region, as a concrete aggregate was evaluated. Red and black shale exported from a Daegu excavation site was selected for use in the experiments and evaluated by comparing with hornfels, which is widely used as a coarse aggregate and is a type of andesite and metamorphosed sedimentary rock. The physical properties of the aggregate were evaluated in accordance with the test methods of KS F 2527 "crushed concrete aggregate," and the compressive strength against the shale aggregate replacement ratio was measured. The compressive strength of the concrete after 28 days was 30.8 MPa when the black shale replaced 100% of the aggregate in the concrete and 31.1 MPa when the red shale replaced 100% of the aggregate in the concrete. Compared with the compressive strength of 37.5 MPa for concrete prepared by using plain aggregate, using shale as a substitute for the aggregate produced an average compressive strength that was 82% of normal concrete.

• The Journal of Engineering Geology
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• v.13 no.1
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• pp.1-16
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• 2003

Geochemical characteristics of groundwater in the different kinds of various lithology such as Haman formation, Panyaweol formation, Jusan andesitic formation and Palgongsan granite is distinguished by mineralogical and chemical compositions. The Concentration of the majority of solutes in groundwaters of Haman and Panyaweol formation is higher than in that of andesite and granite. Higher concentration of $HCO_3^{-}{\;}and{\;}SO_4^{2-}$ anions in the groundwater is peculiar. High concentrations of $Ca^{2+},{\;}Mg^{2+},{\;}HCO_3^{-}$ in the groundwaters of the sedimentary rocks result mainly from reaction of $CO^{2-}$ charged water with calcite and weathered feldspars. With the Piper diagram, the groundwaters of Haman formations are mainly plotted in $CaSO_4-CaCl_2$ type, whereas those of Panyaweol formations are plotted in the bothside of $Ca(HCO_3)_2{\;}and{\;}CaSO_4-CaCl_2$ type. Thses two different types of $Ca(HCO_3)_2{\;}and{\;}CaSO_4-CaCl_2$ groundwater were originated from dissolution of calcite($Ca(HCO_3)_2)$ and the oxidation of pyrite($CaSO_4-CaCl_2$), respectively. And it also is influenced by anthropogenic contamination. Three factors were extracted from the factor analysis for chemical data. Factor 1, controlled by $SO_4^{2-},{\;}Na^{+},{\;}Ca^{2+}$ and Fe, explains the dissolution of calcite, plagioclase and oxidation of pyrite. Factor 2, controlled by $HCO_3^{-}{\;}and{\;}Mg^{2+}$, mainly explains the dissolution of Mg-carbonates and dolomitization. Factor 3, controlled by $Cl^{-},{\;}K^{+}{\;}and{\;}NO_3^{-}$, is subject to the influence of artificial pollution including industrial waste water disposal. In this study area, some industrial complex which is close to Keumho river show the higher score of factor 3.

• Journal of the Korean GEO-environmental Society
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• v.11 no.1
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• pp.13-18
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• 2010

It is crucial to decide reasonably the parameters necessary for design through research on the characteristics of rock in order to analyze stability of rock structure. This article has conducted both pressure meter test, uniaxial and triaxial compression test to the areas of andesite or tuff located in local regions such as Yeosu, Gwangju, Yangsan, Busan, and Daejeon and has comparatively analyzed previously proposed estimative formulas. According to the result of estimating the deformation modulus through using the damping coefficient suggested by Nicholson & Bieniawski, when RMR is less than 60, it is desirable to use the result of the pressure meter test considering the damping coefficient. If the RMR value is over 60, however, the formula suggested by Kim Gyo-won has been proved to be the most applicable. Moreover, according to the result of comparing the RMR, adhesion, and angle of internal friction, both the adhesion and angle of internal friction best correspond to the formula proposed by Tsuchiya. Comparatively analyzing the relations between the rock deformation modulus and RMR and also suggesting the formula of calculating the shear strength parameter to use the RMR value, this study did not include the deformation modulus and shear strength parameter as factors to decide the RMR index. Since result can differ by several factors, it will be necessary afterwards to suggest practical estimative formulas applicable to the actual spots of Korea.

• Journal of the Korean Geotechnical Society
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• v.15 no.1
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• pp.113-125
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• 1999

In this study the occurrence and mineralogical characteristics of clay minerals from the Munhyun-dong landslide area in Pusan city were examined by XRD, SEM, and chemical analyses. Several types of clay minerals such as halloysite, vermiculite, mica/vermiculite interstratified mineral, vermiculite/smectite interstratified mineral, kaolinite and illite are found abundantly in the area. The occurrence of clay minerals suggest that they have been formed by weathering of andesite which is the bedrock of the area. It is believed that halloysite was formed in the early stage of weathering, and vermiculite, mica/vermiculite interstratified mineral and mica/vermiculite interstratified mineral were formed in the middle stage, and finally, kaolinite was formed. The clay minerals occurring in the central part of the landsliding area and within the slip surface are dominated by expandable minerals such as halloysite, vermiculite and vermiculite/smectite interstratified mineral. These clay minerals expand by absorbing water and effectively decrease the shear resistance of the rock mass, and therefore, they could be an important factor for the landslide. The analyses of geology and mineralogical characteristics of the area suggest that the landslide was caused by combination of various factors including steep slope, heavy rainfall, abundant joints, alteration of the rocks, and occurrence of expandable clay minerals. The result of this study suggests that the investigation for the prevention of possible landslide must include the examination of clay mineralogy as well as the site geology.

• The Journal of Engineering Geology
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• v.2 no.2
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• pp.173-200
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• 1992

The quality of groundwater in the central part of Taegu City is influenced by upstreams of Sin-stream and Beomeo-stream because the stream waters are main source of the groundwater, and chemical composition of the upstream waters has close relationship with andesite and monzonite in the igneous rock terrain. The pH of upstreams are weak acid ~ neutral in the igneous rock area and weak alkaline in the sedimentary rock area. Contents of $Ca^{2+}$ and $Mg^{2+}$ in the streams are apparently high, and $Na^{+}$ content is only slightly high in the sedimentary rock area. But $K^{+}$ content is lower in the Panyaweol formation area than in the monzonite area. The contents of heavy metals and $N0_3^{-}$ are also higher in the sedimentary rock area of residential sections and industrial complexes than those in the igneous rock area. The groundwater is contaminated in comparison to the upstream water of the igneous rock areas, and there are some differences in pollution level between the Panyaweol formation area of residential sections and the Haman formation area of industrial complexes. K, Na, Ca, Mg, Cl, $SO_4$ and $NO_3$ contents in the Haman formation area are relatively higher than those in the Panyaweol formation area. But pH is nearly equal in the two areas. The content of heavy metal ions is still lower than the drinking water standard of Korea and only slightly differs in the two sedimentary rock areas. But the groundwater in the Haman formation area is considerably contaminated by Kongdanstream and Dalseo-stream.

• Economic and Environmental Geology
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• v.3 no.2
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• pp.55-73
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• 1970

The district investigated covers the central and southern portions of the Uiryong Quadrangle amounting to $40km^2$ in area and is bounded approximately by geographical coordinates of $128^{\circ}$ 28' $40^{{\prime}{\prime}}{\sim}128^{\circ}$ 24' 25"E in longitude and $35^{\circ}10{\prime}{\sim}35^{\circ}14^{\prime}06^{{\prime}{\prime}}N$ in latitude. The purpose of this investigation was to provide basic information in drawing up a comprehensive development plan of the copper ore deposits known to exist in the HamanKumbuk district with special emphasis given to the ascertainment of geological and paragenetic characteristics. The area consists chiefly of shale, sandy shale and chert, all belong to Kyongsang System of Cretaceous age. Intruded into these rocks are andesite, granodiorite, basic dikes, and acidic dikes. The mineralization which took place in the area, consists of mostly fissure-filling vein deposits, numbering several tens, with varying magnitudes. The fissures and shear zones created in rocks, such as chert and granodiorite, hosted the deposition of mineralizing vapors and/or hydrothermal solutions along their openings. The strike lengths of these veins vary from 50 to 600 meters in extension and 0.1 to 3 meters in width. Although the degree of fluctuation in width is great, it averages 0.3m. The stuctural patterns, which apparently affected the deposition of veins, are fissure patterns, trend NS to $N30^{\circ}W$, and steep-pitching tension fractures as well as normal fault pattern. Ore minerals associated with vein matters are primarily chalcopyrite and small amounts of scheelite, cobaltiferous arsenopyrite, and gold and silver intimately associated with sulphide minerals. Associated with these ore mineral are pyrite, pyrrhotite, magnetite, specularite and arsenopyrite. Gangue minerals noted are quartz, calcite, chlorite, tourmaline and hornblende. In terms of the compositions of associated minerals, the vein deposits in the district could be grouped under the following four categories: 1. Pyrrhoitite, Arsenopyrite, Gold and Silver Bearing Copper Vein (Type I) 2. Calcite-Scheelite-Copper Vein (Type II) 3. Magnetite-Pyrite-Copper Vein (Type III) 4. Tourmaline Copper Vein (Type IV) Of the four types, the first and the fourth are presently yielding relatively higher grades: of copper ores and concentrates. The estimated ore reserves total some 222,000 metric tons with the following breakdown in terms of metal contents: Name of Mines Au(g/t) Ag(g/t) Cu(%) Reserves(M/T) Kunbuk 15.92 78.69 6,074 60.498 Cheil Kunbuk - - 1.040 60,847 Haman - - 2.688 101,204 222,549 As rehabilitation of old workings and/or exploration of veins at depth proceed, additional estimation of ore reserves may become apparent and necessary. With regard to the problem of beneficiation and upgrading of low-grade ores in the district, it would be advisable to make decisions on location, treating capacity and mill flowsheet after sufficient amount of exploration is completed as suggested in the report.

• Tunnel and Underground Space
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• v.10 no.4
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• pp.526-532
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• 2000

The uniaxial compressive strength of rock mass is known as the major factor in the assessment of drillability and the optimum excavation design in full-face tunnel excavation by TBM. Referring to worldwide cases, TBM has been applied mostly to the rock mass within the strength range of 80~250 MPa. Recently, a water way tunnel has been constructed as a part of Milyang dam project by TBM within the rock masses where the rock type is mainly granite with some granophyre, hornfels and andesite. Their uniaxial compressive strengths in extended area are estimated higher than 260 MPa. In this paper, the relation between the penetration rate and the rock mass properties is analyzed and TBM application to the very hard rocks is discussed. As a result that three suggestions to predict the TBM net penetration rate are analyzed, NTH method seems a better approach than other methods in the extremely hard rocks. NTH prediction matches with the results of actual values with the variations of 2~20%. Hardness measurement by Schmidt hammer and RMR estimation are carried out along the L = 5.3 km entire TBM tunnel alignment. The net penetration rate measured monthly is shown to be reciprocally proportional to Schmidt rebound hardness and RMR where coefficients of correlation, $R^2$are 0.705 and 0.777 respectively. As a result, they are good quantitative indices for the prediction of TBM net penetration rate in the extremely hard rocks. Magnitude of in-situ stress has a certain effect on TBM performance, and it is required to measure the in-situ stresses in TBM excavation design.

• The Journal of the Petrological Society of Korea
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• v.9 no.3
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• pp.142-168
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• 2000

The granites distributed in the Kyongsang basin contain the rocks which are different from the host rocks, and they are known as magic microgranular enclaves. The genesis of the magic micro-granular enclaves can be divided into four types: (1) rock fragments from country rocks; (2) cumulation of the early crystals in host magma or disruption of early chilled borders; (3) magma mingling; and (4) restite. These enclaves can be easily found in the granites around Mt. Wonhyo, Yangsan city. They are ellipsoidal in shape, and have phenocrysts might be originated from the host rocks and sharp contacts with the granites. Under the microscope, textures such as oscillation zoning, horn-blende-mantled quartz, rapakivi texture, and acicular apatite are observed, and these indicate that the enclaves were originated from magma and then produced by chilling. The evidences showing that the enclaves were formed by magma mingling are: (1) petrographical characteristics; (2) similarity of the compositions between the rim of plagioclase in the enclave and plagioclase in the granite; (3) linear trends of the major elements; (4) total REE content of the enclaves; and (5) Textural and compositional variations from rim to core in zoned enclaves. The magic end member of the enclave is regarded as the aphyric basaltic andesite in Mt. Sinbul-Youngchui area. The granites around Mt. Wonhyo experienced the magma mingling process which was produced by the injection of mafic magma at about 70 Ma, during the crystal differentiation, and then continued the crystallization. The equigranular granites and the micrographic granites in the study area are considered as the results after the magma mingling process.

• Journal of Conservation Science
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• v.17 s.17
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• pp.73-82
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• 2005

The Bunhwangsaseoktop is the oldest stone brick pagoda in Silla Period. The pagoda body is made by piling small brick-shaped stones trimmed from black andesite and the first-story core has a shrine, which is made by granite. In 1915 it was repaired on a large scale, but now is severely damaged. Many kind of the stone decay like flaking, granular disintegration have occurred especially on the granite surface of the pagoda. In this study have been investigated the stone decay type and its cause in relation to efflorescence on the body part. Various analysis show that the deterioration on the granite is due to the same materials that lead to efflorescence on the body stone surface. The soluble salt like sodium nitrate, calcium sulfate and sodium sulfate come from white joint mortar. This salt solution is recrystallized in the outside of the pagoda, but most of them flow down with rain. In This process the porous granite absorbes the dissolved salts with moisture into the inside by capillary action. In order to reduce this problem, therefore, white joint moral is changed with other less soluble materials. And it is necessary to take steps to prevent water from seep into the inside of the stone, because this water dissolves the white joint mortar.

• The Journal of Engineering Geology
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• v.4 no.3
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• pp.269-281
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• 1994

Microscopic study and X-ray diffraction analysis were carried out to find out rock type, tock forming minerals; and weathering characteristics of rocks at the constructing site of the churyong Tunnel, Kyongju-Gun, Kyongbuk. Seismic velocity and compressional strength were measured to evaluate mechanical properties of rock. The rock of the study area is Jurassic tuff consisting of clay minerals, crystals of quartz and feldspar, fragments of volcanic rocks and shale. Fresh tuff has compressional strength of about $443kg/\textrm{cm}^2$ and seismic velocity of about 3680m/sec in average. It is classified as soft rock. Rock fragment within tuff is andesite and it has compressional strength of about $2500kg/\textrm{cm}^2$ and seismic velocity of about 4340m/sec in average. It is classified as hard rock. A good linear relationship is found between compressional streangth and seismic velocity in both laboratory sample and in-situ rocks. Laboratory samples has seismic velocities faster about 1.5km/sec than those in-situ rocks. It is interpreted that joints, fractures, and water content in the in-situ rocks result in decreas of seismic velocity. As Tuff has more than 50% of clay minerals in matrix and shale fragments, it absorbs water easily in atmospheric condition. Therefore, though the rock in the study area is medium hard rock before weathering, it is weathered very easily in the case of exposure to natural environment, comparing with other rock.