• Journal of Environmental Science International
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• v.7 no.2
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• pp.149-156
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• 1998

Enoronmental problems caused by certain geologic conditions Include pollution of soil by heavy metal, acidization of souls , acid mine drainage, Pound-water pollution, and natural radioactivity, as well as zoo-logical hazards such as landslide and subsidence. The acrid mine drainage contains large amount of heavy metals nO, therefore. cause serious pollution onto the nearby drainage systems and soils. In spite of this prospective environmental danger, few studies have been done on the acid mine drainage derived from non-metallic ore deposits such as pyrophyllitefNapseok) deposits. The sudo-bearing pyrophyllite ores, alteration zones, and mine talllngs of pyrophylllte deposits produce acrid mine drainage by the okidation of weathering. Compared to the fresh host rocks, the ores and altered rocks of pyrophyllite deposits produce acidic solution which contain higher amount of heavy metals because of OeP lower buffering capacity to acrid solution. The pus of urine water and nearby stream water of pyrophyllite deposits are 2.1~3.7, which are strong- ly acidic and much lower than that (6.2~7.2) of upstream water and than that (6.8~7.6) of the stream water derived from the non-mineralized area. This study reveals that this acrid mine drainage can affect the downstream area which is 8km far from the pyrophyllite deposits, even though the drain Is diluted with abundant non-contaminated river water This suggmists that not only acid mine drainage but also the sulfide-bearing sediments originated from the pyrophyllite deposits move downstream and form acidic water through continuous oxidation reaction. The heavy metals such as Pb, Zn, Cu, Cd, Nl, Mn and Fe are enriched In the mine water of low pH, and their contents decrease as the pH of mine water Increases because of the Influx of fresh stream wainer. SoUs of the Pyrophyulte deposits are characterized by high contents of heavy metals. The stream sediments containing the yellowish brown precipitates formed by neutralization of acid mine drainage occur in all parts of the stream derived from the pyrophyllite deposits, and the sediments also contain high amounts of heavy metals. In summary, the acid mine drainage of the pyrophyllite deposits is located in the upstream part of Hoidong water reservoir in Pusan contains large amounts of heavy metals and flows into the Holdong water reservoir without any purification process. To protect the water of Holdong reservoir, the acid mine drainage should be treated with a proper purification process.

• Economic and Environmental Geology
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• v.24 no.2
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• pp.151-165
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• 1991

The Au-Ag deposits of the Euiseong area occurred in quartz veins which filled fissures in Cretaceous sedimentary and volcanic rocks. These ore veins can be classified in two types of deposits based on metallic mineral assemblages as follow: a pyrite type gold-silver deposit (Hoedong mine), characterized by Cu sulfides with Au-Ag alloy, and a Sb-rich silver deposit (Keumdongdo mine), characterized by base metal with Ag-bearing sulfosalts. Mineralogic and fluid inclusion evidences suggest that the ore minerals of these deposits was deposited from initial high temperatures (near $350^{\circ}C$) to later lower temperatures ($200^{\circ}C$) with moderate salinity fluids ranging from 5.8 to 3.8 eq. wt. % NaCl. The gold-silver mineralization of the Hoedong mine occurred at temperatures between 300 and $200^{\circ}C$ from fluids with log $f_{s_2}$ of -10 ~ -16 atm. The antimony - silver mineralization of the Keumdongdo mine were deposited at the higher temperatures (350 to $250^{\circ}C$) and $f_{S_2}$ (-10 ~ -13 atm) than gold mineralization of the Hoedong mine. The calculated log f02 of fluids at $250^{\circ}C$ in two deposits are -32 to -34 atm and -36.5 to -38.5 atm, respectively. Boiling evidences indicate that the ore mineralization of the Hoedong mine occurred at more shallow depth (0.5km) than that (1km) of the Keumdongdo mine. The above differences of depositional environments between two deposits caused the compositional changes of ore minerals such as electrum and sphalerite.

• Economic and Environmental Geology
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• v.5 no.4
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• pp.211-217
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• 1972

The Second Yeon Hwa Mine which belongs to a so called Lead-Zines Belt Area in the central east Korea is located at about 10 km northeast of the Seogpo railway station on Yeongdong Line. The exploitation of the mine started in June, 1969 and furnished the machinary ore dressing plant in November, 1971. The current monthly production of rude ore is 15,000 meteric tons. The results of the study on the lead-zinc-copper deposits of the Second Yeonhwa mine are summerized as follows: (1) main ore deposits of the mine are localized in the Pungchon Limestion formation of Cambrian age, (2) related ingneous rock with ore deposits is granite porphyry, which distributed in NS and $N50^{\circ}W$ trend, (3) ore solution ascended along the $N50^{\circ}W$ trend which represents folding axis and fault plane and mineralized selectively in the limestone formation. (4) high grade ore deposits are localized in concave and convex boundaries of granite porphyry, and hanging walls of shale bed ($P_2S$ shale bed) in Pungchon Limestone formation and (5) skarn minerals are consisted of garnet, hedenbergite, diopside, and sulfide minerals are composed of zincblenede, galena, phyrhotite, pyrite and some amount of chalcopyrite and arsenopyrite.

• Economic and Environmental Geology
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• v.6 no.4
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• pp.195-200
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• 1973

Temperature environments of the formation of fluorite deposits in the Wolaksan area and the Cheonil Mine, Chungcheongbuk-Do are presented and interpreted in brief. These deposits occur more or less near the contact zone between the Paleozoic limestone formations and the Cretaceous biotite granites as a number of hydrothermal veins or replacement deposits. The homogenization temperatures of fluorite crystals from the Wolaksan area fall within the narrow range of $149{\sim}167^{\circ}C$, of which lower limit is quite high, while those of the Cheonil Mine show wide range of $126{\sim}177^{\circ}C$, which indicates much lower mean temperature of formation. If the possible correction for pressure, which may not exceed $+30^{\circ}C$ as the depth of the deposits was 1.5km, were applied, the possible highest value of the true formation temperatures of fluorites in both area might be reached to around $200^{\circ}C$ that means these deposits were formed as a series of early products of the epithermal stage of hydrothermal processes.

• Economic and Environmental Geology
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• v.55 no.2
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• pp.149-169
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• 2022

Indonesia coal is widely consumed as a major energy source in Asian countries, such as China, India, and Korea. In the paper, the characteristics of the coal-bearing basin and coal deposits in Indonesia are comprehensively reviewed using the exploration data accumulated through the coal exploration projects supported by Korean government subsidy. Cenozoic coal bearing sedimentary basins in Indonesia extensively contain coal deposits and are most productive in East Asia. Properties of coal deposits are variable depending on stratigraphy, depositional histories and tectonics. Eocene coal deposits tend to have thinner coal thickness and fewer numbers of coal seams, but have been major exploration targets due to higher calorific value and good coal quality. Late Oligocene-Early Miocene coal deposits occur in small scales, but are suitable enough for small to medium-sized coal mines. Miocene-Pliocene coal deposits, which are widely distributed across East Kalimantan and Sumatra, are being actively mined by taking advantage of thick coal thickness and abundant reserves in spite of their lower calorific values. The experience of various exploration informs that we need to have an overall understanding on geological conditions for successful coal exploration. The details on coal-bearing basin and coal deposits in Indonesia provided through the paper will be useful data for up-coming exploration activities by Korean companies.

• Economic and Environmental Geology
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• v.22 no.3
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• pp.193-205
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• 1989

Regional geology of Chungil mine is composed of Cretaceous biotite granite. Chungil ore deposits are fissure filled quartz veins which developed in Cretaceous biotite granites. Mineralogic and fluid inclusion studies were undertaken to illuminate the origin of the ore deposits. Data gathered from occurrences of ore deposits and mineral paragenesis reveals that there were two major mineralization stage. The first stage is sulfides-quartz stage. The constituents of ore minerals are chalcopyrite, sphalerite, pyrrhotite with minor amount of galena, native Au, Ag, pyrite. The second stage is gangue mineral stage. Gangue minerals are quartz, fluorite and calcite. Homogenization temperature of fluid inclusions in quartz of the first and the second stage ranges from $212^{\circ}C$ to $336^{\circ}C$ and from $154^{\circ}C$ to $355^{\circ}C$ respectively. Homogenization temperature in fluorite and calcite of the second stage ranges from $127^{\circ}C$ to $252^{\circ}C$ and from $129^{\circ}C$ to $158^{\circ}C$ but these data require positive pressure corrections. Fluid inclusions in quartz of the Bongmyeong mine, Jangja the first mine and the second mine show range of homogenization temperature from $178^{\circ}C$ to $330^{\circ}C$, from $185^{\circ}C$ to $354^{\circ}C$ and from $206^{\circ}C$ to 336 respectively. The comparison of the fluid inclusion data, mineralogical component and vein attitude of the three mines with that of Chungil mine indicates that the origin of the deposits above mentioned is elucidated to be formed under similar environment. The compositions of the sphalerite in the first stage range from 16.05 mol.% FeS to 20.36 mol.% FeS.

• Economic and Environmental Geology
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• v.23 no.2
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• pp.161-181
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• 1990

The lead-zinc-silver-iron deposits from the Janggun mine are of hydrothermal-metasomatic origin, characterized by the marked hydrothermal alteration of the wallrocks, such as hydrothermal manganese enrichment of carbonate rocks, silicification, chloritization, sericitization, montmorillonitization and argillic alteration. The ore deposits have been emplaced within the Janggun Limestone of Cambro-Ordovician age at the immediate contacts with apophyses injected from the Chunyang Granite plutons of Late Jurrasic age. They have been structurally controlled by fractures in the carbonate rocks and the irregular intrusive contacts of granitic rocks, and are closely associated with hypogene manganese carbonate deposits. In the mine nine seperate orebodies are being mined. On the basis of the petrological study, hydrothermal alteration zone of this mine may be divided into the following four zones from wallrock to orebody. (I) Primary calcite and dolomite zone${\rightarrow}$(II) dolomitic limestone zone${\rightarrow}$(III) dolomitic zone${\rightarrow}$(IV) rhodochrosite zone${\rightarrow}$ orebody. There was not recongnized Mn and Fe elements in the primary calcite and dolomite zone. But, in the dolomitic limestone and dolomite zone, calcite and dolomite were subjected to weak hydrothermal manganese enrichment and the grade of the manganese enrichment increase oreward. By means of electron probe microanalysis, it was found that manganoan dolomite occured between primary dolomite grains, cross the cleavage of the primary dolomite and around the dolomite grains. Above these result supports that the Janggun manganese carbonate deposits are of hydrothermal metasomatic origin.

• Economic and Environmental Geology
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• v.29 no.1
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• pp.11-21
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• 1996

The first Mg-skarn minerals are found from magnetite ore deposits of the Janggun mine, Korea. The skarn minerals are composed of mostly chondrodite, olivine， chlorite, serpentine, phlogophite, talc, apatite, magnesite， dolomite, siderite and trace amount of clinopyroxene, amphibole, garnet, wollastonite associated with magnetite, pyrrhotite and pyrite. The skarn zone is developed in the magnetite deposits at the contact of the Mg-rich Janggun Limestone Formation and the Chunyang granite. The chondrodites are columnar and radial shapes and some of them show twins. The chemical compositions of twinning-type chondrodites have high FeO (4.63 to 5.6 wt%), MnO (0.26 to 0.46 wt%) and low MgO (55.02 to 56.18 wt%) relative to the radial-type chondrodites. Twinning in chondrodite has been formed in close relation to substitution between Mg and Fe + Mn in humite solid solution. Temperature, $-logfo_2$ and $X_{CO2}$ during the skarn stage of magnetite deposits from the Janggun mine range from 395 to $430^{\circ}C$, from 30.5 to 31.2 atm and from 0.06 to 0.09, respectively.

• Economic and Environmental Geology
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• v.15 no.2
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• pp.89-102
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• 1982

Several mines in Jeonnam produce the ores of having high SK number of refractoriness. Among those for 5 mines, this paper deals with the relationahip between SK number and mineral composition of the ore, and with the genesis of the deposits. 1. Byok-Song and Chon-Un Mine: Mineral compositions of the ores are chiastolite, chloritoid(monoclinic), kaolinite, sericite, diaspore, corundum, and quartz. The ores having SK number of 36 or 37, consist chiefly of chiastolite and diaspore and a little amount of kaolinite, sericite, corundum, chloritoid, and quartz. The ores having SK number of 33 or 34 consist of chloritoid, sericite, kaolinite, chiastolite, and diaspore. With increasing the amount of chloritoid and sericite, and decreasing the amount of diaspore and chiastolite, the SK number of the ores decreases. The deposit, originally high alumina-bearing shale of Chon-Un San formation, seems to be formed by contact metamorphism(forming of chiastolite), regional metamorphism(forming of monoclinic chloritoid), and hydrothermal replacement(forming of large crystal of diaspore veinlets). 2. Song-Sauk Mine: Mineral compositions of the ores are chiefly pyrophyllite and quartz and a little amount of kaolinite, dickite, diaspore, and pyrite. Many spherical inclusions containing in pyrophyllite deposits, consist chiefly of diaspore and kaolinite, The inclusions have the high SK number of 38. Amount of spherical inclusions is about 5 % to the whole pyrophyllite ores. The SK number of other pyrophyllite ore is less than 32. Quartz and pyrite are chief minerals lowering the SK number of the ore. The deposits have been formed by hydrothermal processes by replacing the siliceous tuff of Mesozoic age. Spherical inclusions consisting of diaspore and kaolinite, show the selective replacement of hydrothermal solutions to the materials of feldspar in tuff. 3. Seung-San Mine: Mineral compositions of the ores are chiefly kaolinite, dickite, diaspore, and quartz. But some part of the mine consists of alunite deposits. The ores having SK number of 35 or higher consist chiefly of kaolinite and diaspore and a little amount of quartz. With increasing the amount of quartz and decresing the amount of diaspore, the SK number of the ore decreases. The deposits have been formed by hydrothermal processes by replacing the siliceous tuff and quartz porphyry. 4. Wan-Do Mine: Mineral compositions of the ores are chiefly pyrophyllite and quartz. But some ore contains a little amount of diaspore, kaolinite, pyrite, and chloritoid. The ores having high SK number of 36 consist chiefly of diaspore and pyrophyllite. Pyrophyllite ore has a SK number of 32 or lower. Amount of quartz and pyrite decreases the SK number of ores in this mine. Rhyolite was replaced by the action of hydrothermal solutions forming the pyrophyllite deposits.

• Economic and Environmental Geology
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• v.2 no.3
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• pp.47-57
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• 1969

The Yeonhwa Lead and Zinc Mine is located in northern part of Kyeongsang-Buk-Do, Korea, and is economically most important mine because it produces most part of the output of lead and zinc minerals in the country. Ore deposits of the mine are localized in the Pungchon Formation and several limestone seams of upper Myobong Formation in Cambrian Age. Ore solution ascended along the fractures of N-S, NE-SW or NW-SE trends and along slate and limestone boundary, and then replaced selectively limestone to make ore bodies. Skarn minerals are consisted of hedenbergite, diopside, and main sulfide mineral orebodies are composed of galena, zincblende, pyrrhotite, pyrite and a minor amounts of arsenopyrite and chalcopyrite. Metal ratio, ${\rho}_{Pb}={\frac{Pb(%)}{Pb(%)+Zn(%)}}{\times}100$, illustrates the zona I arrangements of some ore bodies. It will be inferred the flow trending of ore solution and the process reaction with adjacent country rocks. The sub-divided formations of the Pungchon limestone and Myobong slate are very useful as a criteria for detecting probable ore location. Rhodochrosite veins are good evidence for searching of ore location, especially on Pb-rich ore bodies.