• Journal of the Mineralogical Society of Korea
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• v.19 no.3 s.49
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• pp.189-195
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• 2006

Compression work on a pyrite powder has been carried out using energy dispersive X-ray diffraction (EDXRD) with Mao-Bell type diamond anvil cell (DAC) and synchrotron radiation(SR) at room temperature. It has been reported the bulk moduli of pyrite show the large variations depending on the experimental conditions as well as the apparatus used. Thus, two kinds of sample in different pressure transmitting media of both NaCl and MgO powder emerged in alcoholic fluids were subjected to measure their compressibilities. Bulk moduli thus obtained are 138.9 GPa and 198.2 GPa, respectively, and this result contradicts to the anticipated values according to the hydrostaticity conditions of the sample chamber. This might be due to the alcoholic fluids phase transition mainly with the side effects from the difference of both solid state detector (SSD) used and E*d value applied. All experiments were performed at the Beam Line 1B2 of Pohang Light Source (PLS).

• Economic and Environmental Geology
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• v.18 no.3
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• pp.247-251
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• 1985

The sulfide and carbonate mineral samples for sulfur and carbon isotope studies were collected from Sangdong, Geodo, Yeonhwa, Shinyemi and Janggun mines which are distributed in the Metallogenetic Province of the Taebaeg Mt. Region. The ${\delta}S^{34}$ values of molybdenite, pyrite, arsenopyrite, pyrrhotite, chalcopyrite, sphalerite and galena from the above mines are similar and within the range of +1.66 to +6.77‰ with the exception of chalcopyrite from Geodo mine ranging from -1.58 to 1.96‰, while the sulfide minerals are dominated by positive values between +3.05 and +5.08‰. It is suggested that the major sulfur source is genetically related to the Cretaceous granitic activity. The average ${\delta}C^{13}$ values of calcite from limestone, calcite from calcite vein in ore bodies and granite, and rhodochrosite from ore bodies are -0.60‰, -2.69‰ and -6.00‰, respectively. The data on carbon isotope compositions indicate that the calcite from limestone originated in marine environment, the rhodochrosite in hydrothermal solution, and calcite from calcite vein and granite in the mixing condition of marine and hydrothermal waters. The temperatures of mineralization by the sulfur isotopic composition coexisting pyrite-pyrrhotite from Yeonhwa No.1, sphalerite-galena from Weolam and Dong-jeom of Yeonhwa No.1 mine, sphalerite-galena and pyrite-galena from Janggun mine were $273^{\circ}C$, $460{\sim}511^{\circ}C$, $561{\sim}690^{\circ}C$, $341^{\circ}C$ and $375^{\circ}C$, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.4
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• pp.246-252
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• 2017

Pulverized $FeS_2$ (pyrite) gives different discharge test results with as-received $FeS_2$ electrodes. The as-received $FeS_2$ electrode shows three voltage plateaus during the discharge test. However, the ball-milled $FeS_2$ electrode shows two voltage plateaus. To interpret this result, the effect of $FeS_2$ particle size on electrochemical reactions is investigated by unit cell discharge tests, SEM and XRD. As a result, it is found that the transition reaction product ($Li_2+xFe+xS_2$) of $FeS_2$ explains the difference. The as-received $FeS_2$ reacts according to three reaction steps ($FeS_2{\rightarrow}Li_3Fe_2S_4{\rightarrow}Li_2+xFe_1+xS_2{\rightarrow}LiFe_2S_4$). However, ball-milled $FeS_2$ reacts without the $Li_2+xFe_1+xS_2$ stage. In this study, this result is explained by the difference in electrochemical reaction mechanism. The as-received $FeS_2$ has a larger radius than the ball-milled $FeS_2$. Therefore, the lithium ion has to diffuse into the $FeS_2$ unreacted core, and $Li_2+xFe_1+xS_2$, the transition reaction product of as-received $FeS_2$, is formed during this stage.

• Tunnel and Underground Space
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• v.21 no.5
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• pp.341-348
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• 2011

As a result of the detailed site investigation performed for the design of a 4.3 km long tunnel, geological anomalies of four fault zones and a rock boundary were discovered on the tunnel route. Most of all, it was confirmed that pyrite, which may corrode steel material, is contained inside the geological anomalies, and pressured ground water flows out of the fault fractured zone. To overcome these geological conditions, antisulfur concrete for the concrete lining and anticorrosive swelling rock bolts are designed in the pyrite-containing sections. For the sections where a great amount of groundwater outflows, water blocking methods including grouting are applied according to the result of numerical analyses on the seepage. In addition, since the past earthquakes occurred around Korea have take place mainly near fault zones, seismic analyses were performed based on the Soil-Structure Interaction (SSI) concept and the strength of concrete tunnel lining is designed to be 27 MPa from 24 MPa in order to reinforce the tunnel structure.

• The Journal of Engineering Geology
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• v.31 no.4
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• pp.523-532
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• 2021

The treatment of acid rock drainage was reviewed and evaluated for the case of pyrite rocks distributed in a highway embankment. During the highway's construction, neutralization using alkaline water repellent was applied to the embankment section to prevent acid rock drainage. However, it still occurred long after the construction was completed owing to rain infiltration, and the acid rock drainage polluted the surrounding soils and streams. To solve this problem, treatment facilities such as SAPS (Successive Alkalinity Producing Systems) or ecological wetlands and sand filtration were installed. After the installation of the treatment facilities, the effluent and soils contaminated by acid rock drainage nearby the outlet of the facilities were analyzed and evaluated for a period of years. Measurements of the pH of the effluent and analysis of the heavy metal contamination of the soils confirmed that the neutralization treatment for acid rock drainage is being performed properly and that contamination of heavy metals in the acid rock drainage is also being stably controlled by the treatment facilities.

• 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.19 no.spc
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• pp.193-206
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• 1986

A number of auriferous veins occur in the Precambrian metamorphic terrain from Chungju to Mugeug district. These gold (-silver) deposits consist mainly of the fissure-filling quartz veins intruding the Precambrian gneiss or schist and Jurassic or Cretaceous granite. These gold (-silver) deposits can be 'divided into two mineralization epochs, (a) gold-rich veins related to Daebo igneous activity, and (b) gold-silver veins related to Bulgugsa igneous activity. These two groups of ore deposits with different generation can be characterized by the mode of occurrence of ore vein and the ore mineral associations. The auriferous quartz veins of Taechang and Boryeon mines associated with late Jurassic igneous activity are massive in character, and show the simple mineral assemblages and low Ag/Au ratio in the ores, representing a single mineralization system. The ore minerals are predominantly quartz containing minor or trace amonts of pyrrhotite, sphalerite, galena, pyrite, chalcopyrite and electrum. Electrum is closely associated with pyrrhotite and has chemical compositions from 61.4 to 78.5 atomic % Au. Fluid inclusion data suggest that ore minerals were deposited at temperatures between 238 and $390^{\circ}C$ from $CO_2$-rich fluids. The gold and/or silver-bearing quartz veins of Geumwang mine related to middle Cretaceous igneous activity are characterized by the multistage history, diverse mineral assemblages with high Ag/Au ratio in the ores. The ores of Geumwang mine have two contrasting mineral assemblages (1) pyrite+galena+sphalerite+arsenopyrite+electrum+argentite, representing the higher gold mineralization, and (2) pyrite+chalcopyrite+ galena +sphalerite+ arsenopyrite+silver sulfosalts+ electrum+ native silver+argentite, representing the higher silver mineralization. Electrum is closely associated with pyrite and has chemical compositions from 11.2 to 49.9 atomic % Au. The depositional environment during the higher gold mineralization can be estimated as the range of both temperature and sulfur fugacity, T= $200{\sim}300^{\circ}C$, log f ($S_2$) = $10^{-10}{\sim}10^{-15}$. The higher silver mineralization may be interpreted to have formed a range of falling temperature ($150{\sim}200^{\circ}C$) and low sulfur fugacity($10^{-10}{\sim}10^{-15}$). These temperature data are consistent with homogenization temperatures of fluId inclusions in quartz. Thus, the gold veins related to the Daebo igneous activity may be formed by the environment of higher temperature and pressure than the gold-silver veins associated with the Bulgugsa igneous activity.

• The Journal of Engineering Geology
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• v.28 no.3
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• pp.501-512
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• 2018

The acid leachate derived from the sulfide mineral such as pyrite can cause problems such as aging of infrastructure and environment contamination around the civil construction site. The purpose of this study is to assess the environmental effect of an acid leachate derived from pyrite in the Miryang area under road construction. In this study, 13 samples of situ core were used for the net acid generation (NAG) experiment. The chemical composition including pH, oxidation and reduction potential (ORP) and electrical conductance of water samples produced from the NAG test was analyzed. In additional, five polished thin sections of rock cores were made for electro microprobe analyses. In the results of the NAG tests, 7 samples showed lower values than pH 3.5. It strongly indicated that these areas are under the environmental and infrastructure damage by the acid leachate. The chemical type of the 7 samples was classified as the $Fe(Ca)-SO_4$ type, which is totally a different type compared to general groundwater. The concentration of total sulfur ranges from 0.004% to 12.5%. 6 rock samples are plotted on a potentially acid forming zone in the relation diagram between the total sulfide and NAG-pH. In conclusion, it is suggested that a protection method against an environmental demage and an infrastructure corrosions by the acid leachate should be prepared in all of areas under a road construction.

• Journal of the Mineralogical Society of Korea
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• v.29 no.2
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• pp.47-58
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• 2016

The Fe-component of pyrophyllite is an impurity that reduces its grade in the final product. In order to identify the amount of impurity in pyrophyllite and to remove the Fe from the ore using a dry method, microwave heating and magnetic separation were carried out. Pyrite and hematite were identified to contain pyrophyllite by microscopy, XRD, XRF, SEM/EDS and EPMA analysis. It is suggested that the euhedral pyrite in the pyrophyllite is formed by hydrothermal solution, and then the dissolution cavity structure is formed with a partial remainder of the pyrite which dissolved in acidic water. And the $Fe^{3+}$ ion contained in the acidic water precipitated out in the concentric structure of hematite as the origin of sedimentary structure. As a result of the microwave heating and magnetic separation experiments, the Fe removal rates obtained were 96% and 93% from pyrophyllite ore from the Sunsan mine and Wando mine, respectively. It is confirmed that the microwave heating and magnetic separation method was an environmentally friendly method to upgrade the low-grade pyrophyllite.

• Economic and Environmental Geology
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• v.26 no.2
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• pp.145-154
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• 1993

Gold-silver deposits in the Kwangyang-Seungju area are emplaced along $N4^{\circ}{\sim}10^{\circ}W$ to $N40^{\circ}{\sim}60^{\circ}W$ trending fissures and fault in Pre-cambrian Jirisan gneiss complex or Cretaceous diorite. Mineral constituents of the ore from above deposits are composed mainly of pyrite, arsenopyrite, pyrrhotite, magnetite, sphalerite, chalcopyrite, galena and minor amount of electrum, tetrahedrite, miargyrite, stannite, covellite and goethite. The gangue minerals are predominantly quartz and calcite. Gold minerals consist mostly of electrum with a 56.19~79.24 wt% Au and closely associated with pyrite, chalcopyrite, miargyrite and galena. K-Ar analysis of the altered sericite from the Beonjeong mine yielded a date of $94.2{\pm}2.4\;Ma$ (Lee, 1992). This indicates a likely genetic tie between ore mineralization and intrusion of the middle Cretaceous diorite ($108{\pm}4\;Ma$). The ${\delta}^{34}S$ values ranged from +1.0 to 8.3‰ with an average of +4.4‰ suggest that the sulfur in the sulfides may be magmatic origin. The temperatures of mineralization by the sulfur isotopic composition with coexisting pyrite-galena and pyrite-chalcopyrite from Beonjeong and Jeungheung mines were $343^{\circ}C$ and $375^{\circ}C$ respectively. This temperature is in reasonable agreement with the homogenization temperature of primary fluid inclusion quartz ($330^{\circ}C$ to $390^{\circ}C$; Park.1989). Four samples of quartz from ore veins have ${\delta}^{18}O$ values of +6.9~+10.6‰ (mean=8.9‰) and three whole rock samples have ${\delta}^{18}O$ values of +7.4~+10.2‰ with an average of 7.4‰. These values are similar with those of the Cretaceous Bulgugsa granite in South Korea (mean=8.3‰; Kim et al. 1991). The calculated ${\delta}^{18}O_{water}$ in the ore-forming fluid using fractionation factors of Bulgugsa et al. (1973) range from -1.3 to -2.3‰. These values suggest that the fluid was dominated by progressive meteoric water inundation through mineralization.