• Economic and Environmental Geology
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• v.23 no.2
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• pp.183-199
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• 1990

Ore deposits of Dongwon mine are composed of numerous gold and silver veins emplaced in sedimentary rocks of Cambrian Choseon Supergroup and granitoids of Cretaceous age. Ore veins of the mine can be divided into gold and silver veins on the base of vein structure, mineral assemblage and vein trends. Mutual relationships between gold and silver veins are uncertain. Gold veins are simple veins which are composed of base-metal sulfides, and electrum with quartz and ankerite. On the other hand, silver veins are complex veins which reveal three distinct stages of mineral deposition based on vein structure; stage I, deposition of small amounts of oxides and pyrite with quartz; stage II, deposition of base-metal sulfides, small amounts of Ag-bearing minerals, calcite and quartz; stage III, deposition of base metal sulfides, electrum, Ag-sulfosalts, native silver, carbonates and quartz. Homogenization temperature and salinity of fluid inclusion from quartz of gold vein are as follows; $229^{\circ}$ to $283^{\circ}C$, 4.7 to 6.4 wt.% equivalent NaCI. The ore mineralogy suggests that temperature(T) and sulfur fugacity($fs_2$) of the formation of the gold vein and stage III of silver vein are estimated as T ; $294^{\circ}$ to $318^{\circ}C$, $fs_2\;10^{-9.4}$ to $10^{-10.1}$ atm. and T; $240^{\circ}$ to $279^{\circ}C$, $fs_2;10^{-11.1}$ to $10^{-17.3}$ atm. respectively. Pressure condition during gold vein formation estimated from data of ore mineralogy and fluid inclusion range 500 to 750 bar.

• Economic and Environmental Geology
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• v.20 no.1
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• pp.1-18
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• 1987

The Cheolam silver deposits are emplaced along the fractures in breccia dike and the Hongjesa granite. Breccia dike contains fragments of late Cretaceous acidic volcanic rocks and other fragments of various rocks distributed in the mine area. Therefore it is presumed that the mineralization was taken place in later than late Cretaceous time. Mineral paragenesis is complicated by multiple episodes of fracturing. Six distinct depositional stages can be recognized: stage I, deposition of base metal sulfides; stage II, deposition of base metal sulfides and silver minerals; stage III, deposition of carbonates; stage IV, deposition of silver minerals and base metal sulfides; stage V, deposition of silver minerals; stage VI, deposition of barren quartz. Silver minerals from the deposits are native silver, acanthite, pyrargyrite, argentian tetrahedrite, stephanite, polybasite, pearceite, allargentum, antimonial silver and electrum. Fluid inclusion studies ware carried out for stage I, II, IV and VI quartz and stage III calcite. Homogenization temperatures for each stage are as follows: stage I, from $225^{\circ}$ to $360^{\circ}C$; stage II, from $145^{\circ}$ to $220^{\circ}C$; stage III, from $175^{\circ}$ to $240^{\circ}C$; stage IV, from $130^{\circ}$ to $185^{\circ}C$; stage VI, from $120^{\circ}$ to $145^{\circ}C$. Salinities of ore fluids were in the range of 4 and 10 wt.% equivalent NaCl over stage I and stage VI. Ore mineralogical data of each stage indicate that temperatures are within the range of homogenization temperature of fluid inclusions and sulfur fugacities declined steadily from $10^{-9.7}atm$. to $10^{-18.7}atm$. through stage I into stage V.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.3
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• pp.112-117
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• 2018

The metal alkoxide, CuCo-glycerate nanospheres (NSs), were successfully synthesized as Cu-Co bimetallic sulfides hierarchical multi-shelled hollow nanospheres ($CuCo_2S_4$ HMHNSs) through solvothermal synthesis. In this reaction mechanism, the solvothermal temperature and the amount of glycerol as a cosurfactant play significant role to optimize the morphology of CuCo-glycerate NSs. Furthermore, $CuCo_2S_4$ HMHNSs were obtained under optimized sulfurization reaction time of 10 h via anion exchange reaction between glycerate and sulfur ions. Finally, the structural and chemical compositions of CuCo-glycerate NSs and $CuCo_2S_4$ HMHNSs were confirmed through field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and electrochemical performances.

• Economic and Environmental Geology
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• v.21 no.3
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• pp.257-268
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• 1988

The Mugeug gold deposits is consisted of more than fourteen gold and silver-bearing quartz veins emplaced in Mesozoic granodiorite mass. In the Samhyungje vein, one of the representative vein in the mine, six stages of mineralizatidns are recognized: Stage I, deposition of base-metal sulfides and gray quartz; stage II, deposition of base-metal sulfides, electrum and white quartz with pinkish tint; stage m, deposition of base-metal sulfides and dark gray quartz; stage N, deposition of native silver, argentite, Ag-tetrahedrite, polybasite, arsenpolybasite and quartz; stage V, deposition of nearly barren quartz; stage VI, deposition of transparent quartz veinlets with minor pyrite. Ag contents of electrum increase steadily from stage II to stage N; 57.25-61.44 atom. % for stage II, 62.85-69.66 atom. % for stage m, 69.79-74.12 atom. % for stage N. Homogenization temperatures of fluid inclusions are as follows; stage II, from $194^{\circ}$ to $287^{\circ}C$; stage V, from $137^{\circ}$ to $171^{\circ}C$, stage VI, from $192^{\circ}$ to $232^{\circ}C$. Salinities of fluid inclusions range from 3.7 to 7.9 wt.% equivalent NaCl in stage II and from 0.8 to 4.3 wt.% equivalent Nael in stage V. Ore mineralogy suggest that temperature and sulfur fugacity declined steadily from $290^{\circ}$ to $150^{\circ}C$ and from $10^{-10.5}$ to $10^{-19.0}$atm. through stage II into stage N. Fluid pressure during stage II inferred from data of mineral assemblages and fluid inclusions is 370bar.

• Economic and Environmental Geology
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• v.42 no.5
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• pp.445-455
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• 2009

Microbiological sulfate reduction is the transformation of sulfate to sulfide catalyzed by the activity of sulfate-reducing bacteria using sulfate as an electron acceptor. Low solubility of metal sulfides leads to precipitation of the sulfides in solution. The effects of microbiological sulfate reduction on in-situ precipitation of arsenic and copper were investigated for the heavy metal-contaminated soil around the Songcheon Au-Ag mine site. Total concentrations of As, Cu, and Pb were 1,311 mg/kg, 146 mg/kg, and 294 mg/kg, respectively, after aqua regia digestion. In batch-type experiments, indigenous sulfate-reducing bacteria rapidly decreased sulfate concentration and redox potential and led to substantial removal of dissolved As and Cu from solution. Optimal concentrations of carbon source and sulfate for effective microbial sulfate reduction were 0.2~0.5% (w/v) and 100~200 mg/L, respectively. More than 98% of injected As and Cu were removed in the effluents from both microbial and chemical columns designed for metal sulfides to be precipitated. However, after the injection of oxygen-rich solution, the microbial column showed the enhanced long-term stability of in-situ precipitated metals when compared with the chemical column which showed immediate increase in dissolved As and Cu due to oxidative dissolution of the sulfides. Black precipitates formed in the microbial column during the experiments and were identified as iron sulfide and copper sulfide. Arsenic was observed to be adsorbed on surface of iron sulfide precipitate.

• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.3120-3122
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• 2009

• Journal of Korean Society of Environmental Engineers
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• v.36 no.7
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• pp.469-475
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• 2014

The study investigated the physicochemical characteristics and the ecological risk of the Northport sediment in B city and the releasing properties of heavy metals into seawater during the resuspension also studied. The major components of the sediment are fine silt and clay which contains high organic matter and AVS (Acid volatile sulfide) and the ecological risk of the heavy metals in sediment also very high. The release rate of heavy metals into seawater was in order of Pb>>Cu>Cr>>Zn>Cd during the resuspension in a batch experiment, and the heavy metal release mainly attributed to the oxidation of metal sulfides. Heavy metals which came from easily oxidisable metal sulfides rapidly contaminated seawater within about 1.0 h of the sediment resuspension. The sulfide oxidation during the resuspension increased the residual fraction of heavy metals in the sediment, decreased the organic bound fraction, and changed the other fractions of heavy metals in the sediment. The release of heavy metals from the sediment during resuspension was affected by the resuspension time, the oxidation rate of metal sulfides and resuspended concentration of the sediment particle.

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

Magnetite ores of the Janggun mine are embedded in dolomitic limestone of the Janggun Limestone Formation contacting with Chunyang granite, and are closely associated with skarn minerals. Mineralization of magnetite deposits can be divided into two stages as deep-seated skarn stage and shallow hydrothermal replacement stage. Mineralogies of skarn stage consist of magnetite, pyrrhotite and base-metal sulfides, and those of hydrothermal stage is base-metal sulfides, native bismuth, bismuthinite, tetrahedrite, boulangerite, bournonite and stannite. The FeS mole % in sphalerite and As atom % in arsenopyrite range from 22.47 to 26.30 and from 31.39 to 31.66 in skarn stage, and are from 17.54 to 32.54 and 28.87 to 30.70 in hydrothermal stage, respectively. Based on mineralization characteristics, mineral assemblages, chemical compositions and thermodynamic considerations, formation temperatures, sulfur fugacities ($-logf_2$), pH and oxygen fugacity ($-logfo_2$) estimated to be from 345 to $382^{\circ}C$, from 8.1 to 9.7atm, from 6.5 to 7.2 and from 30.5 to 31.2atm in the skarn stage, respectively, and temperature and $-logfs_2$ are from 245 to $315^{\circ}C$ and from 10.4 to 13.2atm in the hydrothermal stage.

• Economic and Environmental Geology
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• v.20 no.2
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• pp.107-118
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• 1987

The south ore deposits of the Dunjeon gold mine is a fissure-filling vein emplaced in the granitoids, skarnized and hornfelsified rocks of Ordovician Dumudong formation. The vein mineral paragenesis is complicated by repeated fracturing but three distinct depositional stages can be recognized; (1) base metal sulfides stage, (2) base metal sulfides, antimony-bismuthsulfosalts and native metals stage, (3) barren carbonates stage. Gold was mainly deposited in stage II. Fluid inclusion data indicate that fluid temperatures were from $310^{\circ}C$ to $402^{\circ}C$ during stage I and then declined steadily to $148^{\circ}C$ in the closing late stage III. Salinities were in the range of 0.4 to 5.0 equivalent weight percent NaCl and do not reveals any systematic trend through stag I, II and III. Ore mineralogy suggests that temperatures and sulfur fugacities in the earlier stage II were in the range of $340^{\circ}C$ to $360^{\circ}C$, $10^{-8}$ to $10^{-9}$ atm. respectively and then declined steadily to the range of $185^{\circ}C$ to $200^{\circ}C$ and $10^{-17}$ to $10^{-19}$atm. in the later stage II.

• Economic and Environmental Geology
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• v.29 no.3
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• pp.395-405
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• 1996

The Donjin deposits which is located in the Chinan Basin, are emplaced along $N10{\sim}40^{\circ}E$ trending fissure sets. So it is a sort of fissure-filling ore deposits. The results of paragenetic studies suggest two stages of hydrothermal mineralization; stage I: base-metal sulfides stage, stage II: late base-metal sulfides, electrum and silver-bearing sulfosalts stage. Au: Ag ratios of the electrums show that Ag atomic% are higher than that of Au. The temperature and salinity of the Donjin deposits estimated from fluid inclusion and sulfur isotope geothermometry are as follows; stage I: $240{\sim}315^{\circ}C$, 2.4~7.1 NaCl eq. wt.%, stage II: $190{\sim}268^{\circ}C$, 4.6~8.4 NaCl eq. wt.%. The estimated oxygen and sulfur fugacity during first stage mineralization, based on phase relation of associated minerals, range from $10^{-35}{\sim}10^{-39.7}$ atm. and$10^{-11}{\sim}10^{-13.4}$ atm., respectively. All these evidences suggest that the Dongjin deposits are polymetallic meso-epithermal ore deposits.