• Tunnel and Underground Space
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• v.25 no.2
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• pp.186-198
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• 2015

This paper aims for the ultimate goal to optimize the work place environment through assuring the optimal required ventilation rate based on the analysis of the airflow. The working environment is deteriorated due to a rise in temperature of a coal mine caused by increase of its depth and carriage tunnels. To improve the environment, the ventilation evaluation on J coal mine is carried out and the effect of a length of the tunnel on the temperature to enhance the ventilation efficiency in the subsurface is numerically analyzed. The analysis shows that J coal mine needs $17,831m^3/min$ for in-flow ventilation rate but the total input air flowrate is $16,474m^3/min$, $1,357m^3/min$ of in-flow ventilation rate shortage. The temperatures were predicted on the two developed models of J mine, and VnetPC that is a numerical program for the flowrate prediction. The result of the simulation notices the temperature in the case of developing all 4 areas of -425ML as a first model is predicted 29.30 at the main gangway 9X of C section and in the case of developing 3 areas of -425ML excepting A area as a second model, it is predicted 27.45 Celsius degrees.

• The Optical Journal
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• v.12 no.5 s.69
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• pp.47-53
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• 2000

1998년 일본 내 생산실적은 5조 6,342억엔, 1999년 일본 내 생산실적 6조 4,191억엔으로 성장률 저하 경향이 1998년 경계로 상승 무드로 전환됐다. 인터넷의 폭발적인 신장에 따른 디스플레이 소자의 증산 및 대 화면 제품의 시장 진출, 광전송기기 장치 등의 신장이 크게 기여했다. 2000년은 $17.1\%$ 성장한 7조 5,170억엔이 예측된다.

• The Journal of Engineering Geology
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• v.18 no.3
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• pp.257-262
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• 2008

In the study it was investigated the diffusion characteristics of heavy metal pollutions such as Cu, Pb, Hg and As which was the main pollution sources of soils from abandoned mines. The pollution of Cu and Pb was caused by Mine A, that of Hg was caused by Mine 3, that of Pb was caused by Mine C and that of Cu, Pb, As was caused by Mine D. Though the high concentration was detected within 100m from abandoned mines, the low concentration was detected over than 100m from abandoned mines in all heavy metals investigated except As. It means that it was very difficult to estimate the pollution level of As caused abandoned mines. The results were discussed in the concentrations of Cu, Pb and distances showed a good relationship with 0.71 and 0.68 as the coefficient of correlation, respectively. In particular the relativity of Cu to Pb as very strong with 0.84 as the coefficient of correlation. It was consistent with the chemical behavior in soils in the case of Cu and Pb. Therefore it will be a promising approach to remove Cu and Pb with estimated values in the study.

• Explosives and Blasting
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• v.31 no.2
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• pp.6-13
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• 2013

Recently, complaints or environmental problems caused by the noise and dust generated from crusher of the mine and quarry are emerging. Therefore mining facilities such as crushers and mills have been installed in an underground. In order to facilitate crusher equipments in the underground, excavation of large space is required and then the stability of the large space underground structure is an important issue. In this study, the blast experiments, which use a block of the limestone, are performed. Based on the blast experiments, the numerical model was prepared and simulated using dynamic fracture process analysis code(DFPA) with considering the rising time of applied borehole pressure and microscopic tensile strength variation. Comparing the non-dimensional crack length and no-dimensional tensile strength obtained from blast experiments and numerical analyses, the input parameters of DFPA code for predicting a radial tensile crack in limestone blasting were determined.

• Tunnel and Underground Space
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• v.18 no.4
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• pp.272-279
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• 2008

This paper describes the development of a simple and quantitative subsidence hazard estimation method appropriate to Korean coal mines using gangway depth information only. In spite of simpleness of estimation method, this new method gives good results close to those obtained using influence function method when applying to a virtual rectangular excavation model and to a closed mine where actual subsidence occurred. Therefore, this method can be effectively applied to the identification of zones liable to subsidence over closed coal mine in Korea where the shape of extraction is very complex and usually unknown.

• Tunnel and Underground Space
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• v.24 no.4
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• pp.282-288
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• 2014

Stoping method has been acknowledged as one of the typical metalliferous underground mining methods. Notwithstanding with the popularity of the method, the majority of stoping mines are suffering from excessive unplanned dilution which often becomes as the main cause of mine closure. Thus a reliable unplanned dilution management system is imperatively needed. In this study, reliable unplanned dilution prediction system is introduced by adopting artificial neural network (ANN) based on data investigated from one underground stoping mine in Western Australia. In addition, contributions of input parameters were analysed by connection weight algorithm (CWA). To validate the reliability of the proposed ANN, correlation coefficient (R) was calculated in the training and test stage which shown relatively high correlation of 0.9641 in training and 0.7933 in test stage. As results of CWA application, BHL (Length of blast hole) and SFJ (Safety factor of Joint orientation) show comparatively high contribution of 18.78% and 19.77% which imply that these are somewhat critical influential parameter of unplanned dilution.

• Economic and Environmental Geology
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• v.37 no.1
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• pp.35-48
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• 2004

This paper provides a comprehensive overview of geochemical approaches for investigating and assessing heavy metal contamination in abandoned mine sites. Major sources of contaminants at the abandoned mine sites are mine water, waste rocks, tailings, and chemicals used in beneficiation and mineral processing. Soil, sediment, surface and ground water, and ecological system can be contaminated by heavy metals, which are transported due to erosion of mine waste piles, discharge of acid mine drainage and processed water, and dispersion of dust from waste rocks and tailings. The abandoned mine sites should be characterized using various methods including chemical analysis, mineralogical analysis, acid generation prediction tests, leaching/extraction tests, and field tests. Potential and practical environmental impacts from the abandoned mines should be assessed based on the site characterization.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.392-395
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• 2004

광미와 오염된 토양에 함유되어 있는 중금속은 물리ㆍ화학적 환경 변화에 따라 안정화되어 자연적으로 정화가 진행되거나, 혹은 재용출 될 수 있어 중요한 오염원으로 작용 할 수 있다. 따라서 중금속 원소의 존재형태를 규명하여 물리ㆍ화학적 환경 변화에 따른 중금속의 거동을 예측하고자 Tessier et al (1979)의 방법을 이용하여 연속추출을 수행하였다. 구룡광간의 광미와 오염된 토양에 함유된 중금속과 마량원소의 존재형태를 비교해 보면 Fe를 제외한 모든 원소의 존재형태가 안정상인 잔류형태로 존재하였다. Cd, Co, Cu 및 Pb의 경우 잔류형태 다음으로 비정질 산화광물형태로 수반된 형태도 중요한 존재 형태인 것으로 나타났다. 그러나 Fe은 비정질 산화광물의 형태가 가장 우세한 것으로 나타났으며, 황화광물과의 결합형태가 상대적으로 우세한 경향을 보였다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.403-405
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• 2004

일반적으로 폐광산 지역에 방치되어 있는 광미와 오염토양에 함유된 중금속원소는 자연 상태에서 물리ㆍ화학적 환경의 변화에 따라 자연정화 되거나, 또는 재용출되어 점 또는 비점오염원으로의 역할을 하기 때문에 광미와 오염된 토양에 존재하는 중금속의 존재형태를 규명 또는 예측하는 것은 매우 중요하다. 이에 따른 중금속의 오염평가와 존재형태를 규명하기 위해 서성 연ㆍ아연 폐광산 주변 경작토를 대상으로 Tessier et at. (1979)가 제시한 연속추출을 실시하였다. 그 결과는 As와 Cr이 잔류형태가 우세하여 안정한 상태로 존재하는 것으로 평가되었으며, 이에 반하여 Zn, Pb, Cu, Cd, Ni 및 Mn 등은 상대적으로 존재형태가 불안정한 것으로 평가되었다. 특히, As는 모두가 잔류형태로만 존재하는 것이 확인되어 As의 오염이 야기되지 않는 것으로 밝혀졌다.

• Photonics industry news
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• s.7
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• pp.10-13
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• 2001

한국 전자통신연구원(ETRI)은 지난 1976년 창립 이래 25년간 전전자식교환기(TDX), 초고집적 반도체(DRAM), 슈퍼미니컴퓨터(TiCOM), 디지털이동통신시스템(CDMA)등 경쟁력 있는 정보통신 기술개발을 성공적으로 수행하여 우리나라가 정보통신 강국으로 발돋움하는 데 획기적인 기여를 해 온 국내 최대의 종합 정보통신 국책 연구기관이다. 21세기는 지식과 정보가 컴퓨터나 통신기능과 결합해 훨씬 높은 효율로 활용되는 지식기반사회가 될 것이다. 이러한 21세기를 맞이하여 한국전자통신연구원은 세계 최고의 정보통신연구기관이 되기 위하여 ‘세계적인 지적 재산권 다수 보유’, ‘세계적인 우수 인력 확보’, ‘세계 최고의 1인당 기술료 실현’의 발전비전을 수립, 이의 실현을 위해 최선의 노력을 기울이고 있다. 또한 우리나라 산업경쟁력 향상뿐 만 아니라 인류복지를 지향하는 정보통신기술의 선도자이자 Global Leader가 되기 위하여 일신경영 ∙ 품질경영 ∙ 지식경영을 바탕으로 하여 경영혁신을 중점적으로 추진해 나가고 있다. 연구원은 21세기 정보통신 산업구조와 기술동향을 예측, 시대의 요구에 부응하는 새로운 지식과 기술을 창조하여 새 천년에는 세계를 선도하는 전자∙정보통신분야 종합연구기관으로 거듭 태어나도록 최선을 다해 나가고 있다.