• Economic and Environmental Geology
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• v.54 no.4
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• pp.483-494
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• 2021

This study was carried out to investigate the feasibility of reducing clean cover soil using a flooded column test in arsenic-contaminated farmland reclamation of abandoned coal mine area that shows generally low or about worrisome level (25 mg/kg) of Korea soil environment conservation act unlike abandoned metal mine. During the monitoring period of soil solution for 4 months, chemical properties (pH, EC, ORP, Fe, Mn, Ca, and As) in each layer (clean soil cover and contaminated/stabilized soil) showed different variation. This result revealed that soil solution in stabilized or contaminated soil rarely affected that in cover soil. Whether stabilized or not, arsenic concentrations in the rice roots grown in the soil covers with the thickness of 40 cm decreased by 98% in compared with the that grown in the control soil. In case of the soil covers with 20 cm thickness on stabilized soil, it decreased by 80% and this was 22 percentage point higher than when the soil of lower layer was not stabilized. Thus, reducing clean cover soil could be possible in contaminated farmland soil reclamation if appropriate stabilization of contaminated soil is carried.

• The Journal of Engineering Geology
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• v.22 no.2
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• pp.157-171
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• 2012

The slope design of an open-pit mine must ensure slope stability and economic feasibility. The overall slope angle of the pit is therefore the main factor of concern because of limited support or reinforcement options available in such a setting. This study examines the optimal measurement system for monitoring the behavior of the slope in an open-pit mine using displacement measurement, data analysis, and numerical simulations for a coal mine at Pasir, Indonesia. The area of slope to be managed is extensive and the maximum displacement, as calculated by numerical analysis, is about 3,000 mm. The displacement data, measured by inclinometer and GPS, were analyzed, and the applicability of SSR (slope stability radar) was reviewed in comparison with other monitoring systems.

• Resources Recycling
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• v.24 no.4
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• pp.61-66
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• 2015

Cyanidation has been used worldwide to recover gold from primary ore or concentrate. The use of cyanide is however becoming an emerging issue because of the toxic residue and wastewater made from the process. The cyanide-containing wastewater should be treated properly, obeying the environmental standard and regulations. In the present article, the domestic and international uses, regulations, and treatment technologies of cyanide in gold mining were investigated as a feasibility study to develop a cyanide treatment process as well as the cyanidation process. A biological cyanide treatment process to develop a zeroemission gold recovery and wastewater treatment process was also briefly introduced.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.6
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• pp.76-85
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• 2009

This study was carried to select the proper vegetation base materials which improve soil quality in abandoned coal mine areas. Also, we aimed at the feasibility of the direct seeding method without soil molding for the ecological restoration in those areas. We set total eight plots within the study site established on an abandoned coal mine area near Taebaek city, Gangwon province in April 2006. The plots were classified as two groups(straw mats mulching and no mulching), and the four treatments (C; control, MI; microbial innoculation, WC; wood chip, OF; organic fertilizer) were applied in each two groups for the soil conditioning. The survival of Pinus densiflora was highest among other species(Betula platyphylla var. japonica, Amorpha fruticosa and Arundinella hirta). For the non straw mat, the survival rate of Pinus densiflora seedlings was highest in the WC treatment($1,756trees/m^2$). For the straw mat, survival rate of Pinus densiflora seedlings was also highest in the WC treatment ($1,622trees/m^2$). In addition, for the non straw mat, the height growth of Pinus densiflora seedling was highest in the OF treatment($12.4{\pm}3.9cm$). For the straw mat, the height growth of Pinus densiflora seedling was also highest in the OF treatment($18.7{\pm}5.3cm$). In general, organic fertilizer treatment with the straw mat was most effective for seedling growth. Also, we suggested that the direct seeding method without soil molding could be sufficiently possible for revegetating abandoned coal mine, Korea.

• Journal of Environmental Impact Assessment
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• v.32 no.3
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• pp.157-165
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• 2023

In Korea, a major contaminant of farmland soils in the vicinity of abandoned mines is arsenic, for which the general soil reclamation method is contaminated soil stabilization and cover the stabilized soil with clean soil at a thickness of 40 cm. In a previous pot experiment study we confirmed the feasibility of a lower thickness (20 cm) of covering soil for such reclamation in abandoned coal mines, where arsenic contamination levels are generally lower than in metal mines. In this subsequent study a field experiment including rice plant cultivation in field test plots was conducted. For over 4 months, the transfer of arsenic from the contaminated soil to the unpolished rice grains was reduced by 44% when a clean soil covering with a thickness of 20 cm was applied. The maximum decrease (56%) was shown when the stabilization process was performed before the covering. These results reveal a lower thickness of clean soil covering has a high feasibility and it can increase cost-efficiency in the reclamation of an abandoned coal mine.

• Journal of Soil and Groundwater Environment
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• v.26 no.6
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• pp.18-26
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• 2021

Soil aggregation begins with flocculation of clay particles triggered by interfacial reactions of polyvalent cation such as Ca²⁺ and Fe³⁺, and they are also known as important elements to control the mobility of arsenic in soil environment. The objective of this study was to investigate the feasibility of CMDS (coal mine drainage sludge) for soil loss reduction and stabilization of arsenic-contaminated soil in a 37% sloped farmland under rainfall simulation. The amount of soil loss decreased by 43% when CMDS was applied, and this result was not significantly different from the case of limestone application, which yielded 46% decrease of soil loss. However, the relative amount of dispersed clay particles in the sediment CMDS-applied soil was 10% lower than that of limestone-applied soil, suggesting CMDS is more effective than limestone in inducing soil aggregation. The concentrations of bioavailable arsenic in CMDS amended soil decreased by 46%~78%, which was lower than the amount in limestone amended soil. Therefore, CMDS can be used as an effective amendment material to reduce soil loss and stabilize arsenic in sloped farmland areas.

• Geomechanics and Engineering
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• v.30 no.6
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• pp.503-515
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• 2022

The permeability coefficient is an essential parameter for the study of seepage flow in fractured rock mass. This paper discusses the feasibility and application value of using readily available RQD (rock quality index) data to estimate mine water inflow and grouting quantity. Firstly, the influence of different fracture frequencies on permeability in a unit area was explored by combining numerical simulation and experiment, and the relationship between fracture frequencies and pressure and flow velocity at the monitoring point in fractured rock mass was obtained. Then, the stochastic function generation program was used to establish the flow analysis model in fractured rock mass to explore the relationship between flow velocity, pressure and analyze the universal law between fracture frequency and permeability. The concepts of fracture width and connectivity are introduced to modify the permeability calculation formula and grouting formula. Finally, based on the on-site grouting water control example, the rock mass quality index is used to estimate the mine water inflow and the grouting quantity. The results show that it is feasible to estimate the fracture frequency and then calculate the permeability coefficient by RQD. The relationship between fracture frequency and RQD is in accordance with exponential function, and the relationship between structure surface frequency and permeability is also in accordance with exponential function. The calculation results are in good agreement with the field monitoring results, which verifies the rationality of the calculation method. The relationship between the rock mass RQD index and the rock mass permeability established in this paper can be used to invert the mechanical parameters of the rock mass or to judge the permeability and safety of the rock mass by using the mechanical parameters of the rock mass, which is of great significance to the prediction of mine water inflow and the safety evaluation of water inrush disaster management.

• Economic and Environmental Geology
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• v.41 no.3
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• pp.287-297
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• 2008

In order to estimate the preliminary development feasibility according to the commodity, the content of 8 strategic metallic commoditites(Pb, Zn, Cu, Fe, Mo, W, Au, U) in 68 ore specimens obtained from 34 metallic mines within the Taebaegsan-Hwanggangri mineralized zone were analyzed. Analytical results are as follows. The ore specimen of Sangdong mine contained 23% copper(cut-off grade=0.7%) and those of Cheongil and Samhwanghak mines contained average 5% zinc(cut-off grade=2.0%). Especially, the detailed investigation on the above-mentioned mines is required. And, in case of molybdenum(cut-off grade=0.02%) content in Yeonhwa No. 2(0.04%) and Hong-cheon mine(0.02%), and lead(cut-off grade=0.58%) content in Wongasa mine(0.70%), and gold(cut-off grade=10ppm) content in Dongmyoung(279ppm) and Samhwanghak mine(251ppm), it is required to elastically carry out the revaluation on reopening of mines in terms of the international metal price. On the other hand, in case of uranium, iron and tungsten, it is thought that there are no mines with the development potential value in this study.

• The Journal of Engineering Geology
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• v.33 no.4
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• pp.737-753
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• 2023

Abandoned mines represent unused space resulting from resource use and changes in industrial environments. Efforts are underway to repurpose such underground spaces, leveraging their unique attributes of temperature stability, shading, and security. This study aimed to assess the feasibility of operating high-demand data centers and public sports facilities as potential recycling options for abandoned mine spaces. The status of data centers located in abandoned mines abroad was examined, including their operational technology capitalizing on the advantages of underground spaces. Considering the varying sizes of underground spaces in different types of abandoned mine in South Korea, the suitability of installing facilities for 12 different sports was evaluated for potential contributions to the health and welfare of local residents. The utilization of abandoned mine spaces as data centers and public sports facilities is expected to not only recycle industrial heritage but also to allow new development opportunities for local communities.

• Journal of Environmental Science International
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• v.17 no.2
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• pp.185-193
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• 2008

This study has been carried out to examine the feasibility of soil washing process for reducing arsenic contamination level of soil around $Dalch\hat{e}n$ Mine. The results of physicochemical tests of the target soil showed that pH was weak alkalic ($pH{\simeq}7.8$), soil texture was coarse sand, and organic contents (5.7%) and CEC (Cation exchange capacity; 21.5 meq/100 g) were similar with those of soils generally found in Korea. Contamination levels of arsenic were found to over 201 mg/kg which exceed the Korea standard levels of countermeasure and concern. To investigate chemical partitioning of heavy metals, sequential extraction procedures were adopted and it was found that arsenic was predominantly associated with the residual fraction among five fractional forms as much as over 85%, which is demonstrating that only less than 15% of all might be vulnerable to a selected washing agents. Among 6 kinds of washing agents applied on the screening for arsenic-contaminated soil, HCl and $H_3PO_4$ solution were selected as promising washing agents. In comparison with HCl and $H_3PO_4$ solutions for arsenic washing by kinetic experiment in the change of pH, soil-solution ratio, temperature, and washing solution concentration, $H_3PO_4$ solution was determined to best one of agents tested, which showed faster washing rate than HCl to accomplish regulatory goal.