• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.1
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• pp.129-139
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• 2015

Concrete-Face Rock-Fill Dams (CFRDs) are rock-fill dams with watertight-concrete slabs on its upstream slope instead of its central earth cores. The design for CFRDs are still largely empirical and typically based on past experiences. This paper presents a description of the concrete face slabs and leakage behaviors of two post-constructed CFRDs based on the data gathered through instrumentation during the initial impoundment. The results show that the strain on the concrete face slab and the horizontal displacements of the vertical slab joints are slightly affected by both the seasonal temperature change and water loading during the initial impoundment. The deformation of perimetric joints are less affected by the temperature change, however it is significantly affected by the water loading during the initial impoundment. The leakage rate is significantly affected by the hydrostatic load and the deformation of the perimetric joints.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.11a
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• pp.189-194
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• 1998

Geochemical study was carried out to find out the distribution of metals and cyanide in soil in the vicinity of the abandoned Keum-Jung mine. Chemical analysis showed that content of As in soil around tailings exceeded 15mg/kg, Korean standard of soil contamination in the farm land. That means the contamination of soil by As is due to input of tailings. According to total decomposition of tailings, As was highly concentrated in tailings. However the water in tailings impoundment was changed to acidic and contaminated by metal and sulfate because the tailings in the top of the tailings impoundment had been oxidized. Acid mine drainage contaminated the water course in the vicinity of the paddy soils. The proper measures are required to prevent contamination of the soil and water in the vicinity of the Keum-Jung mine.

• Geomechanics and Engineering
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• v.19 no.5
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• pp.383-392
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• 2019

How to safely and economically dispose mining tailings is a challenge to mine operators. This paper presents an alternative upstream method for tailings dam construction, termed as the template construction method (TCM), which has been successfully implemented at Zhelamuqing tailings impoundment since 2004. By the beginning of 2015, the tailings dam wall had reached 95 m in height for the 46 upstream raises, with the total height of the dam including the starter dyke being 128 m. The proposed TCM is relatively simple and cost-effective and provides a good way for constructing rapidly raising tailings dam based on this case.

• Journal of Korea Soil Environment Society
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• v.4 no.1
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• pp.25-34
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• 1999

This geochemical study was carried out to find out the distribution of metals and cyanide in the soils around the Keum-Jung abandoned mine. Chemical analysis showed that extractable As contents in the soils near the mine exceeded 15mg/kg, Korean standard of soil contamination for farm land. The Results suggests that As contamination is due to input of tailings in the soils. According to total decomposition of tailings, As was highly concentrated in tailings. The water in a tailings impoundment was changed to acidic and contaminated by metals and sulfate which were released through oxidation of impoundment. Acid mine drainage from the tailings impoundment distribution channels directed to the paddy soils. The proper measures are required to prevent contamination of the soil and water in the vicinity of the Keum-Jung mine.

• Journal of Korea Soil Environment Society
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• v.2 no.3
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• pp.39-47
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• 1997

Geochemical study was carried out to find out the distribution of metals and cyanide in soil in the vicinity of the abandoned Daduck mine and the reason for acid mine drainage occurrence in the tailings impoundment. Chemical analysis showed that content of As in soil around tailings exceeded 15mg/kg, Korean standard of soil contamination in the farm land. That means the contamination of soil by As is due to input of tailings. According to total decomposition of tailings, As, Cd, Cu, Pb, Zn and S were highly concentrated in tailings. However the water in tailings impoundment was changed to acidic and contaminated by metals and sulfate because the tailings in the top of the tailings impoundment had been oxidized. Acid mine drainage contaminated the water course in the vicinity of the paddy soils. The proper measures are required to prevent contamination of the soil and water in the vicinity of the Daduck mine.

• Journal of Soil and Groundwater Environment
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• v.16 no.1
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• pp.19-31
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• 2011

This study had been carried out to investigate spatial and temporal variations of the concentrations of trace metals for contaminated surface water in creek affected by leachate from the tailings impoundment of the Yeonhwa II mine for about 2 years. It was also to ascertain the metal removal efficiency for potentially deleterious metals by the artificial and natural attenuation processes such as retention ponds and hydrologic mixing of uncontaminated tributaries. The concentrations of As, Pb, Cd, and Cu for leachate in the rainy season were not detected. On the other hand, the concentrations of Zn, Fe, Mn, Al, and $SO_4^{2-}$ in the rainy season for leachate were 2-66 times higher than those in the dry season, due to the oxidation of the sulfide minerals and the dissolution of the secondary minerals. The concentrations of Zn and Cd for leachate and surface water of the upper creek in the rainy season exceeded the criteria of River Water Quality and Drinking Water Quality but in the dry season, those of analyzed all the metals (As, Pb, Cd, Cu, Zn, Cd, Fe, Mn, and Al) for surface water sampled at the study area were below the criteria of River Water Quality and Drinking Water Quality. In regard of the attenuation efficiency for the concentrations of metals, Fe, Mn, Al, Zn, Cd, As, and Cu were removed highly at retention ponds, while the removal efficiency for major cations and sulfate ($SO_4^{2-}$) were related to mixing of the uncontaminated tributaries. Therefore, the major attenuation processes of the metal and sulfate contents in creek affected by leachate from a tailing dump were precipitation (accompanied by metal co-precipitation and sorption), water dilution, and neutralization.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1C
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• pp.17-25
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• 2010

Electrophoresis may offer a new technique to repair in service leaking geomembrane liner of municipal solid waste (MSW) impoundment. The method involves introducing a suspended clay particles, which are charged negatively, into the leakage in geomembrane liners by electrokinetic phenomena and formation of clay cake around leakage for prevention of leachate outflows. Therefore, the 3-dimensional leakage simulation experiments are conducted to evaluate the field applicability of sealing leaks of waste impoundment. In addition, the adequateness of optimum influence factors deduced from 1-dimensional experiments is evaluated. After the test, the total size (width, length) of clay cake formation around leak is increased with enlargement of leakage diameter and distance decrease detween anode and cathode.

• Geomechanics and Engineering
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• v.21 no.1
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• pp.63-71
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• 2020

Strength anisotropy is a typical feature of thin-bedded rock masses and their strength will be degraded subjected to water immersion effect. Such effect is crucial for the operation of hydropower plant because the impoundment lifts the water level of upstream reservoir and causes the rock mass of nearby slopes saturated. So far, researches regarding mechanical property of natural thin-bedded rock masses and their strength variation under water immersion based on field test method are rarely reported. This paper focuses on a thin-bedded stratified rock mass and carries out field test to investigate the mechanical property and strength variation characteristics. The field test is highlighted by samples which have a large shear dimension of 0.5 m*0.5 m, representing a more realistic in-situ situation than small size specimen. The test results confirm the anisotropic nature of the concerned rock mass, whose shear strength of host rocks is significantly larger than that of bedding planes. Further, the comparison of shear strength parameters of the thin-bedded rock mass under natural and saturated conditions show that for both host rocks and bedding planes, the decreasing extent of cohesion values are larger than friction values. The quantitative results are then adopted to analyze the influence of reservoir impoundment of a hydropower plant on the surrounding rock mass stability of diversion tunnels which are located in the nearby slope bank. It is evaluated that after reservoir impoundment, the strength degradation induced incremental deformations of surrounding rock mass of diversion tunnels are small and the stresses in lining structure are acceptable. It is therefore concluded that the influences of impoundment are small and the stability of diversion tunnels can be still achieved. The finings regarding field test method and its results, as well as the numerical evaluation conclusions are hoped to provide references for rock projects with similar concerns.

• Journal of Environmental Impact Assessment
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• v.20 no.1
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• pp.89-96
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• 2011

This study was carried out to assess the variations of water quality caused by the dam construction on the river. Six dams-Yongdam, Miryang, Hoengseong, Boryeong, Jangheung and Buan- constructed recently in Korea were selected for the study. Chemical oxygen demand(COD) was increased in the initial stage of water storage at dams compared to the lotic(river) environment, but after 3 years it was maintained lower and stabilized concentrations. Five dams except for Jangheung Dam were maintained Ia~Ib grade conditions under the water quality criteria of Korea. The concentrations of total nitrogen(T-N) were decreased under the lentic(reservoir) environment compared to the river status. Total phosphorus(T-P) was decreased 13~63% at the reservoir condition. We concluded that increase of COD concentration was due to the debris organic materials of the land, but temporary phenomenon. T-N and T-P concentrations were decreased at the lentic condition compared to the lotic.

• Ecology and Resilient Infrastructure
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• v.4 no.1
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• pp.3-11
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• 2017

In this study, change in vegetation on bars was analyzed using the data on hydrology and river morphology with on-site photographic monitoring data for the sites of interest of the Naeseong Stream during the period from March 2013 to July 2016 when the impoundment of Yeongju Dam began. The effect of flow condition on burial and removal of vegetation covered on bar surfaces was elucidated by comparison of on-site photographic monitoring data with continuous water level plotted with on the cross-section profile. In 2014 burial happened due to late flood, while July flood caused burial and removal in 2016. On the contrary vegetation increased in 2015 due to low flow without flood. Results of this study showing natural changes in vegetation will be reference to changes which is expected to be caused by dam impoundment.