• Economic and Environmental Geology
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• v.14 no.3
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• pp.111-122
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• 1981

This study is a model analysis for an effective application of the geophysical prospecting to the investigation of geological structures or useful resources, and the purpose of it is to research a property of the electrical resistivity prospecting, especially by using a Three-Point electrode array method. In using the Three-Point electrode array method, it is theoretically assumed to choose the infinite for a distance between the two current electrodes, however it is impossible in applying to the practical field prospecting. Therefore this study was conducted for determination and presentation of a minimum appropriate distance between the two current electrodes by making a study on prospecting effect in the variation of distance between both the electrodes. In case that the ratios of the distance between the two current electrodes to that between the two potential electrodes are respectively chosen for 40, 400, 5,000, the experimental data of this study showed that the minimum appropriate distance between the two current electrodes is forty times as much as that between two potential electrodes. In order to make clear a problem about prospecting depth which is essential to the data processing, it had been chosen equally to the distance between two potential electrodes. As a result of it, it was shown that the anomaly is appeared along the position of an assumed ore body. Consequently it was found out that the prospecting depth of the Three-Point electrode array method is the same as the distance between the two potential electrodes. From the model experiment on the sheeting ore body(or linear structure) of horizontal, dipping of $30^{\circ}$, $60^{\circ}$ and vertical on the basis of above experimental condition, it was found out that the position and dip of assumed ore body could be inferred from the aspects of the equiresistivity curve. In consequence of performing out the simultaneous Normal and Reversal electrode movement, it was shown that the electrode movement of the Reversal forms the anomaly more clearly than that of Normal when the sheeting ore body is situated obliquely, therefore it could be ascertained that the electrode movement have to be performed simultaneously in the manner of Normal and Reversal. It was also exhibited that the aspect of the equiresistivity curve forms symmetrically when an assumed ore body (or linear structure) is situated horizontally or vertically, that is, symmetrically, and moreover that the aspect of the equiresistivity curve forms unsymmetrically when an assumed ore body (or linear structure) is situated obliquely. On the basis of these experimental analysis it is thought that it can be inferred from the aspect of equiresistivity curve whether an assumed ore body is obliquely situated or not.

• Economic and Environmental Geology
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• v.3 no.3
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• pp.169-176
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• 1970

Kubong Gold Mine is located in Kuryongri, Sayang-myun, Chungyang-gun, Choongchung-Namdo.(latitude $36^{\circ}24^{\prime}N$. longitude $126^{\circ}45^{\prime}30^{{\prime}{\prime}}E$) The mine was begun to work soon after the inhabitants of this village had accidently discovered the outcrops in April 1908. It is one of the largest gold mines in Korea which produces 4,500 tons of crude ore a month. The geology in the area consists of granitic gneiss, banded gneiss, augen-gneiss, mica schist, limesilicate of Pre-Cambrian series and sedimentary rocks(sandstones & conglomerates) of Daedong series. Basic dikes intrude the former formations. The country rock of the ore deposit is a group of the metamorphic rocks mentioned above. Gold-silver bearing quartz vein contains small amounts of pyrite, chalcopyrite, arsenopyrite, galena and sphalerite in which gold and silver occur as native state. The vein strikes $N30^{\circ}{\sim}60^{\circ}E$ and dips $20^{\circ}{\sim}50^{\circ}S$ and the average width of the vein is estimated 1 to 1.5m. Average grade of ore is Au:6~8gr/t and Ag:5~6gr/t. The ore shoot continues from the outcrop to the depth of -1760ML with dip of $20{\sim}25^{\circ}$ and strike extension reaches to 400m at the depth of -1440 ML and to more or less 200m at below. Highgrade of ore vein was found at the lowest level of the ore shoot at the time of recent field survey at the end of August 1970. Its average grade was estimated as Au:20gr/t and its width 1~2.5M in average. A series of futher prospecting for other new ore shoot or parallel veins are urgent and crosscut prospecting along the horizontal level is strongly recommended.

• Economic and Environmental Geology
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• v.2 no.1
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• pp.13-33
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• 1969

The Mulkum mine, located in Mulkum-myon, Yangsan-Kun, Kyeongsang Province, is one of the biggest iron mine in Korea. The geology of this mine and its vicinity consists of Chusan andesitic rocks and Datae-dong andesite porphyry of the Kyeongsang System which were intruded by biotite granite widely distributed near the vicinity of Mulkum-ni. The ore deposits, embedded in Dotae-dong andesite porphyry, are fissure-filling vein type in origin. Up to present ore bodies of Main vein, No. 2 vein, Eastern No. 1, 2 vein and Western No. 1 vein are exploited. Generally the veins strike N 10-25 E and dip to 60-90 SE. The proved length of vein is more than 500 meters and its depth 150 meters in Main vein with 3-4 meters of thickness in average. Ore minerals are mainly magnetite and locally associated with small amounts of hematite, sphecularite and chalcopyrite. Gangue minerals are quartz, epidote, chlorite, pyroxene, and garnet, etc. The modes of occurrence of vein are as follow; 1. Branching and parallel vein patterns are observed around main shaft in -1 level. 2. Multiple cymoid loops and subrectangular vein patterns are observed around main shaft in -2 level. 2. Single vein patterns are observed in -3 and -5 level. The ore-shoots plunge northeasterly about 20-30 degrees. In conclusion, the tectonically fractured zone belongs to the poorly mineralized zone and shoots are formed as single vein type. The general trends of one-shoots must be applied the prospecting of the deep-seated ore body in the deposits.

• Economic and Environmental Geology
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• v.3 no.3
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• pp.177-186
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• 1970

Bupyong lead-silver mine is located at outskirt of Inchon, a harbor city on the Yellow Sea about 40 km due west of Seoul. The geology of the area is composed of gneisses of pre-Cambrian age, rhyolite of Jurassic to Cretaceous age which extruded over the gneisses and late Cretaceous granite. Small diabasic dike is observed only in the underground. The contact plane between overlying rhyolite and underlain gneiss is sinuous and generally pitches about $30^{\circ}{\sim}40^{\circ}$ toward east. Conjugate joints and fissures are well developed in the rhyolite striking generally north-southward. Three ore bodies are being exploited and three more are under prospecting. These ore bodies range from few tons of hundred thousand to million tons in reserve. These ore bodies occur exclusively in the rhyolite along joints as network and/or desseminated type. The lower limit of ore bodies is always delineated at about 20~30m above the gneiss which might be indicative of ore genesis that has not been clearly explained so far. Two hypothesis on ore genesis could, however, be considered: firstly lithologic difference in the rhyolite might be a manifestation of different flows along which ore solution ascended and replaced along joints; secondly diabasic dike has acted as ore bringer since the dike contains considerable amount of silver, lead and zine. Ore minerals are galena and native silver accompanied by pyrite, argentite, pyragyrite and magnetite. It is believed that pyritization took place in advance to main mineralization, and ore deposit is classified as meso- to epi-thermal type.

• Journal of the Korean earth science society
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• v.30 no.7
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• pp.921-925
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• 2009

It is introduced briefly to understand the overall state of mineral resources of Argentina profile of 30 major ore deposits and mining projects. Prospecting deposits are mostly concentrated on the Northwestern and Midwestern area in Argentina and this fact implies that deposit formation is strongly related to Andean Orogeny. Argentina is important mineral exporting country for copper, gold, silver, lead, zinc, lithium and boron. For a long-term strategy of fuel energy and mineral supply active cooperation of geological research and mine business between Korea and Argentina is needed.

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.13-20
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• 2008

Magnetic method is rapid, cheap and simple geophysical exploration technique, and has wide range of applications such as resources prospecting, geological structure investigation and even geotechnical and environmental problems. Documents during Japanese occupation says that magnetic method was used for exploring metallic ore deposits and hot spring, and that a geomagnetic observatory was operated. From mid 1950's, magnetic explorations for natural resources such as metallic ore, uranium, coal, and groundwater were intensively executed for industrialization. Magnetic survey techniques were rapidly advanced during 1970's and 1980's with improvements of instruments, growth of geophysical manpower, and availability of computers. Decline of mining industry since mid 1980's moved the exploration objects from traditional resources to new ones such as groundwater and geothermal resources. Recently appeared applications such as natural hazard assessment, and engineering and environmental studies increased the magnetic method's utility in the realm of exploration.

• Economic and Environmental Geology
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• v.39 no.4 s.179
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• pp.403-416
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• 2006

Magnetic method is rapid, cheap and simple geophysical exploration technique, and has wide range of applications such as resources prospecting, geological structure investigation and even geotechnical and environmental problems. Especially, aeromagnetics gives fundamental and useful geoscientific data fnr not only assessment of potential resources, but also national land planning. Magnetic method, perhaps the oldest geophysical technique, was relatively early introduced into Korea. Documents during Japanese occupation says that magnetic method was used for exploring metallic ore deposits and hot spring, and that a geomagnetic observatory was operated. From mid 1950's, after Korean War, magnetic explorations for natural resources such as metallic ore, uranium, coal, and groundwater were intensively executed for industrialization. Apache aeromagnetic survey project during $1958{\sim}1959$ and its ground follow-up surveys are typical and important cases in those days. Magnetic survey techniques were rapidly advanced during 1970's and 1980's with improvements of instruments, growth of geophysical manpower, and availability of computers. The national aeromagnetic mapping project by KIGAM in 1981 showed the improved technical capability of those days. Decline of mining industry since mid 1980's moved the exploration objects from traditional resources to new ones such as groundwater and geothermal resources, and applications to investigation of geological structure were revived. Recently appeared applications such as natural hazard assessment, and engineering and environmental studies increased the magnetic method's utility in the realm of exploration.

• Journal of the Mineralogical Society of Korea
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• v.26 no.4
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• pp.285-297
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• 2013

Ilmenite deposits are developed along the Precambrian intercumulated anorthosite body in Jikjeon-Ri, Bukcheon-Myeon, Hadong, Korea. Both detailed geological survey and drilling prospecting data for seven boreholes can be used to do resource estimation with GOCAD S/W. 3D modeling using geostatistics is applied to predict the shape and size of Ti ore bodies. As a result, 5 Ti ore veins occurred along N-S direction and average grade of Ti and ilmenite resources are calculated as 2.98 wt% Ti and 7,494,303 metric tons ilmenite ore reserves (Ti 223,330 t). This 3D modeling will be applied to the whole ilmenite deposits in Hadong-Sancheong area to predict the exact distribution and resources estimations of Ti ores.

• Journal of the Mineralogical Society of Korea
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• v.25 no.4
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• pp.295-304
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• 2012

Ilmenite mine was developed in the anorthosites which intruded Precambrian Jirisan gneiss complex in Wolheongri, Okjong-myeon, Hadong. Ti-ore bodies are confined to the intercumulated type anorthosites, where REE-bearing allanite occurred as veins. The chemistry of allanites shows relatively low in CaO (11.02~12.81 wt%), but high in ${\Sigma}R_2O_3$ (R = Ce, La, Nd) (17.21~21.58 wt%), respectively. Abnormally high radioactive detection ascribes to the presence of small particles of thorium mineral known as thorite ($ThSiO_4$). Thorite shows 65~72.78 wt% ($ThO_2$) and 5.49~12.78 wt% ($UO_2$) in composition. The radioactive prospecting could be a strong tool to find REE-bearing allanite which is closely associated with Ti-ore deposits.

• Economic and Environmental Geology
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• v.12 no.2
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• pp.79-93
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• 1979

Twenty five samples of the scheelite-powellite series from twelve Korean tungsten deposits of various geologic settings were studied mineralogically and geochemically. Variations in the trace-element contents of the scheelite minerals are considered in relation to geologic settings and mineralogic properties. Scheelites from ore deposits developed in similar geologic settings and under similar physicochemical conditions are characterized by specific combinations of trace elements.