• Geomechanics and Engineering
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• 제29권6호
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• pp.627-643
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• 2022

Water-rock interactions have a significant influence on the mechanical behavior of rocks. In this study, uniaxial compression and tension tests on different water-treated sandstone samples were conducted. Acoustic emission (AE) monitoring and micro-pore structure detection were carried out. Water-rock interactions and their effects on rock mechanical behavior were discussed. The results indicate that water content significantly weakens rock mechanical strength. The sensitivity of the mechanical parameters to water treatment, from high to low, are Poisson ratio (𝜇), uniaxial tensile strength (UTS), uniaxial compressive strength (UCS), elastic modulus (E), and peak strain (𝜀). After water treatment, AE activities and the shear crack percentage are reduced, the angles between macro fractures and loading direction are minimized, the dynamic phenomenon during loading is weakened, and the failure mode changes from a mixed tensile-shear type to a tensile one. Due to the softening, lubrication, and water wedge effects in water-rock interactions, water content increases pore size, promotes crack development, and weakens micro-pore structures. Further damage of rocks in fractured and caved zones due to the water-rock interactions leads to an extra load on the adjoining coal and rock masses, which will increase the risk of dynamic disasters.

• Corrosion Science and Technology
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• 제23권2호
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• pp.93-103
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• 2024

In the present work, a phase-field model for dendritic solidification is applied to hot-dip ZnAlMg coatings to elucidate the morphology of zinc dendrites and the solute segregation leading to the formation of eutectics. These aspects define the microstructure that conditions the corrosion resistance and the mechanical behaviour of the coating. Along with modelling phase transformation and solute diffusion, the implemented model is partially coupled with the tracking of crystal orientation in solid grains, thus allowing the effects of surface tension anisotropy to be considered in multi-dendrite simulations. For this purpose, the composition of a hot-dip ZnAlMg coating is assimilated to a dilute pseudo-binary system. 1D and 2D simulations of isothermal solidification are performed in a finite element solver by introducing nuclei as initial conditions. The results are qualitatively consistent with existing analytical solutions for growth velocity and concentration profiles, but the spatial domain of the simulations is limited by the required mesh refinement.

• 유기물자원화
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• 제5권1호
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• pp.71-85
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• 1997

현재 우리나라에서 휴 폐광된 광산수는 약 500여개가 넘는 것으로 추정되고 있다. 휴 폐광된 광산은 경관의 저해 및 분진발생, 중금속에 의한 토양, 지하수 및 하천오염, 산성광산 배수의 생선, 지반붕괴 등 안전사고의 위험 등의 환경문제를 안고 있다. 국내에서 조사된 일부 휴 폐광된 금속광산의 오염현황을 보면 폐석 방치, 침출수, 갱내수의 유출, 인근 하천 및 토양의 중금속 오염, 시설물의 붕괴위험을 안고 있는 폐광산이 상당히 발견되고 있다. 휴 폐광된 광산의 관리대책으로서는 법규를 정비하여 토양환경보전법에 광산지역의 토양오염기준 복원기준 등이 설정되어야 한다. 또한 광산폐수, 폐기물을 적절히 처리해야 하며 지반침하대책 및 폐광의 지하공간 활용 등에 관한 연구가 진행되어야한다. 이러한 대책을 추진하기 위해서는 무엇보다도 먼저 휴 폐광에 대한 조사가 선행되어야 하며 오염복원순위의 설정, 재원 및 전문인력의 확충이 필요하다.

• 한국환경농학회지
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• 제33권4호
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• pp.239-244
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• 2014

BACKGROUND: Heavy metals contamination of soils in the vicinity of abandoned mines in South Korea has been investigated. However, PAHs contamination rarely has been studied. Both heavy metals and PAHs concentrations have been measured in this study. METHODS AND RESULTS: The samples of soil and sediment were collected from the vicinities of three abandoned coal mines and two abandoned metal mines for analysis of heavy metals contaminants and PAHs concentration from April to September 2012. After preparation of these samples following the Korean standard test method for soils, the concentrations of heavy metals contaminants and PAHs were measured using ICP-OES and GC-MS, respectively. It was observed that the concentration of Arsenic was above the concern level based on 'area 1' suggested by Korean soil conservation law, resulting that Arsenic is the main contaminant in these areas. Also Cd, Cu, Pb and Zn were observed as a partial contaminants. The concentrations of other investigated components including benzo(a)pyrene were less than the concern level. CONCLUSION: The correlation observed between Arsenic (as main contaminant) and PAHs concentrations suggested that the contaminant source and pathway are different for each other. The effect of mine activity on PAHs concentration was rarely observed.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.167-174
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• 2004

Several metalliferous and coal mines, including Myungjin, Seojin and Okdong located at the upper watershed of Okdong stream, were abandoned or closed since 1988 due to the mining industry promotion policy and thus disposed an enormous amount of mining wastes without a proper treatment facilities, resulting in water pollution in the downstream areas. AMD and waste effluents from the closed coal mines were very strongly acidic showing pH ranges of 2.7 to 4.5 and had a high level of total dissolved solid (TDS) showing the ranges of 1,030 to 1,947 mg/L. Also heavy metal concentrations in these samples such as Fe, Cu, Cd and anion such as sulfate were very high. These parameters of AMD and effluents were considered to be highly polluted as compared to those in the main stream area of the Okdong river and be major pollutants for water and soil in tile downstream area. Pollution indices of the surface water at the upper stream of Okdong river where AMD of the abandoned coal mines was flowed into main stream were in the ranges of 16.3 to 47.1. On the other hand, those at the mid stream where effluents from tailing dams and coal mines flowed into main stream were in tile ranges of 10.6 to 19.5. However, those at the lower stream were ranged from 10.6 to 14.9 These results indicated that mining wastes such as AMD and effluents from the closed mines were tile major source to water pollution at the Okdong stream areas.

• 한국조경학회지
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• 제34권6호
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• pp.111-129
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• 2007

Industrial heritage artifacts may include the industrial products, technologies and infrastructures that have contributed to modernization beginning with the Industrial Revolution. The history of our industrial heritage spans 50 to 150 years and can be characterized by taking into account the site and the technology. This paper analyzes 13 precedents in Japan, Canada, and the United States in terms of these concerns, with focus on the reuse of abandoned mines as industrial heritage. Field surveys and interviews about each abandoned mine were used to obtain historical records and material. The results describe progress in three phases (1) recognizing phase, (2) organizing phase, and (3) maintenance management phase. A proper methodology for reuse is necessary to ensure the authenticity of the abandoned mine, particularly in the face of poor tourism-oriented approaches. As a result of analyzing the 13 cases, we determined that the following principles should be considered during the reuse process. Firstly, reuse of abandoned mines should not be compulsory but should be a spontaneous process and especially, should be carried out by inhabitants. Secondly, education and real experiences in the abandoned mine should be used to ive visitors a feeling of authenticity. Thirdly, creative remodeling methods can be used to enhance the abandoned mine's facilities and the site. Finally, historic and new functions should be the focus of the revitalization. Because this paper mainly focused on 13 precedents, there are likely more diverse cases. However, the conclusions of this report have practical value for reuse of abandoned mines and can be used in establishing methods for reusing Korean abandoned mines as industrial heritage.

• 터널과지하공간
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• 제13권6호
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• pp.421-433
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• 2003

자원개발에 있어서 환경문제로 석회석광산의 채굴이 노천에서 지하채굴로 점차 전환되면서 석회석 채광에 따르는 갱도의 안전문제가 대두되고 있다. 무지보로 유지해야 하는 갱도의 크기문제를 결정하는 것이 현장에서 가장 어려 문제중의 하나이다. 따라서 석회석 지하채광장과 갱도에서 Q시스템과 RMR 암반분류법을 적용하여 지하갱도의 안전성을 평가하기 위한 암반분류법을 개발하기 위해서 두 개의 석회석 광산을 대상으로 암반조사가 이루어 졌다. 기본적으로 Q 시스템과 RMR 암반분류법의 상관관계를 이용하여, 석회석 광산에 적용할 수 있도록 암반분류법을 수정하였고 또한 무지보 안전갱도 폭을 결정하기 위한 새로운 시도가 이루어 졌다.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.522-525
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• 2003

Mine waters, surface waters and groundwaters were sampled around seven Au-Ag mine areas (Dongil, Okdong, Dongjung, Songcheon, Ssangjeon, Dogok and Gubong Au-Ag mines). The main contamination sources of As in these abandoned Au-Ag mines can be suggested as mine tailings and waste rocks including the sulfide gangue minerals (arsenopyrite). The relatively high concentration of As in mine waters was shown in the Dongil (524 ${\mu}g/L$) and the Dogok (56 ${\mu}g/L$) mine areas. Arsenic concentrations in stream waters from the Dongil ($0.9\~118{\mu}g/L$), the Songchon ($0.8\~63{\mu}g/L$), the Ssangjeon ($1.6\~109{\mu}g/L$) and the Gubong ($3.6\~63{\mu}g/L$) mine areas exceeded the permissible level for stream water in Korea. Groundwaters collected from the Dongil ($0.9\~64{\mu}g/L$ ), the Okdong ($0.2\~69{\mu}g/L$) and the Gubong ($0.5\~101{\mu}g/L$) mine areas contained high As concentration to cause the arsenicosis in these areas. In As speciation, the concentration ratios of As(III) to As(total) present up to $75\%$ and $100\%$ in stream waters from the Okdong and the Songcheon mines, and $70\%$ in groundwaters from the Okdong and the Dongjung mines. Arsenic concentration decreases downstream from the tailing dump correlatively with pH and Fe concentration. Highly elevated As concentrations are found in the dry season (such as April and March) than in the wet season (September) due to the dilution effect by heavy rain during summer in stream waters from the Dongil and the Songcheon mine areas.

• Geomechanics and Engineering
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• 제11권5호
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• pp.607-624
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• 2016

Rockburst is becoming more serious in Chinese coal mine. One of the effective methods to control rockburst is blasting. In the paper, we monitored and analyzed the blasting waves at different blast center distances by the Hilbert-Huang transform (HHT) in a coal mine. Results show that with the increase of blast center distance, the main frequency and amplitude of blasting waves show the decreasing trend. The attenuation of blasting waves is slower in the near blast field (10-75 m), compared with the far blast field (75-230 m). Besides, the frequency superposition phenomenon aggravates in the far field. A majority of the blasting waves energy at different blast center distances is concentrated around the IMF components 1-3. The instantaneous energy peak shows attenuation trend with the blast center distance increase, there are two obvious energy peaks in the near blast field (10-75 m), the energy spectrum appears "fat", and the total energy is greater. By contrast, there is only an energy peak in the far blast field, the energy spectrum is "thin", and the total energy is lesser. The HHT three dimensional spectrum shows that the wave energy accumulates in the time and frequency with the increasing of blast center distance.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2001년도 정기총회 및 제3회 특별지포지움
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• pp.75-89
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• 2001

국내 폐석탄 광산은 334 개, 폐금속 광산은 약 900 여개로 알려져 있다. 이러한 폐광산에서는 환경오염과 지반침하 등 안전문제가 발생하고 있다. 폐광산에서 환경오염은 주로 폐갱도, 채굴적 그리고 광산폐기물 적치장에서 유출되는 산성광산배수 문제와 중금속이 함유된 광산폐기물의 침식 및 유실로 인한 주변 토양오염 등을 들 수 있다. 폐석탄 광산 및 폐금속 광산의 갱내수를 조사 분석한 결과, 일부 폐광산 갱내수들은 산성수이며 금속성분이 고농도로 함유된 폐수로 나타나고 폐탄광 배수의 수질은 지역적으로 차이가 있다. 폐광산배수의 정화는 물리화학적 처리시 막대한 운영비가 소요되므로 폐갱도 석회석 충전과 소택지 등 자연정화처리법으로 처리되고 있다. 현재 폐금속 광산 폐기물은 환경오염 방지를 위해 주로 매립법으로 복구되고 있다.