• Tunnel and Underground Space
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• v.26 no.1
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• pp.1-11
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• 2016

This study deals with the case that was the field application of the microseismic monitoring techniques for the stability monitoring in a domestic mine. The usefulness and limitations of the microseismic techniques were examined through analyzing the microseismic monitored data. The target limestone mine adopted a hybrid room-and-pillar mining method to improve the extraction ratio. The accelerometers were installed in each vertical pillar within the test bed which has the horizontal cross-section $50m{\times}50m$. The measured signals were divided into 4 types; blasting induced signal, drilling induced signal, damage induced signal, and electric noise. The stability analysis was performed based on the measured damage induced signals. After the blasting in the mining section close to the test bed, the damage of the pillar was increased and rockfall near the test bed could be estimated from monitored microseismic data. It was possible to assess the pillar stability from the changes of daily monitored data and the proposed safety criteria from the accumulated monitored data. However, there was a difficulty to determine the 3D microseismic source positions due to the 2D local sensor arrays. Also, it was needed to use real-time monitoring methods in domestic mines. By complementing the problems encountered in the mine application and comparing microseismic monitored data with mining operations, the microseismic monitoring technique can be used as a better safety method.

• Photonics industry news
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• s.33
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• pp.34-41
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• 2006

광통신은 인터넷 이용자의 증가와 디지털기술 발전에 의한 화상정보 활용의 보편화, 전자 상거래, 양방향 TV등 전송 데이터가 폭증하는 정보화 사회의 필수적인 기술이다. 이는 광섬유 한 가닥의 정보전달 능력이 수십 Gbps이며 전자파 장애에 의한 누화나 잡음이 없고 수명이 길다는 장점이 있기 때문이다.

• Tunnel and Underground Space
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• v.19 no.5
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• pp.463-472
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• 2009

Many old domestic mines were excavated with the room and pillar method or the sublevel caving method and they involve the great possibility of surface subsidence, especially in the shallow depth mines. In most of these cases, the mine roadways and openings are very irregular in shape and the information about the local geology is uncertain. Consequently it is not simple to standardize the estimation method for the possibility of subsidence, especially the sinkhole subsidence. In this study, the fuzzy reasoning method has been applied for development of estimating the possibility of subsidence occurrence in abandoned mine area. This method has the advantage in producing the reliable estimation results with a simple performance procedure even when the precise information on the local geology and mining conditions is rare. For the verification of applicability of this method, the developed method has been applied to Kumho mine in Bonghwa, Kyungbook province and the Choong-ju mine in Iryu, Choongbook province where the surface subsidence occurred already.

• Journal of the Mineralogical Society of Korea
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• v.19 no.3 s.49
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• pp.171-187
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• 2006

The status of heavy metal contamination was investigated using chemical analyses of stream waters and sediments obtained from Samsanjeil and Sambong Cu mining area in Goseong-gun, Gyeongsangnam-do. In addition, the degree and the environmental risk of heavy metal contamination in stream sediments was assessed through pollution index (Pl) and danger index (DI) based on total digestion by aqua regia and fractionation of heavy metal contaminants by sequential extraction, respectively. Not only the degree of heavy metal contamination was significantly higher in Samsanjeil area than in Sambong area, but its environmental risk was also revealed much more serious in Samsanjeil area than in Sambong area. The differences in status and level of contamination and environmental risk between both two mining areas may be attributed to existence of contamination source and geology. Acid mine drainage is continuously discharged and flows into the stream in Samsanjeil mining area, and it makes the heavy metal contamination in the stream more deteriorated than in Sambong mining area in which acid mine drainage is not produced. In addition, the geology of Samsanjeil mining area is mainly comprised of andesitic rocks including a small amount of calcite and having lower pH buffering capacity fer acid mine drainage, and it is likely that the heavy metal contamination cannot be naturally attenuated in streams. On the contrary, the main geology of Sambong mining area consists of pyroclastic sedimentary Goseong formation containing a high content of carbonates, particularly calcite, and it seems that these carbonates of high pH buffering capacity prevent the heavy metal contamination from proceeding downstream in stream within that area.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.11a
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• pp.583-587
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• 1998

본 논문에서는 대형 탱커선의 의무 장비인 유배출 감시 장비 (Oil Discharge Monitoring Equipment)를 위한 유분 농도계의 설계에 대하여 연구하였다. ODME는 국제해사기구 (IMO)에서 일정 ton 이상의 대형 선박에 의무적으로 설치하도록 규정하고 있으며 이는 날로 심각해지는 해양 오염을 방지하는데 목적이 있다. ODME의 구성 요소는 중앙 제어 장치, 유분 농도계, 유량계, 선속계, Sampling System, 배출 제어 장치로 이루어져 있으며 이중 가장 중요한 것은 유분 농도계이다. 이는 선박에서 배출되는 물에 포함된 유 성분을 ppm 단위로 계측하는 것이다. 이를 위한 탁도 측정 방법에는 여러 가지가 있지만, 본 연구에서는 선박에서 사용이 용이한 광산란 방식과 방폭성을 가지는 광섬유를 이용하여 탁도를 측정하는 유분 농도계를 설계하였으며 아울러 이에 대한 탁도 계산 알고리즘에 대하여 고찰하였다. 측정의 정밀도는 0-999ppm 범위에서 $\pm$5%의 오차 이내로 측정이 가능함을 보였다. 이는 IMO의 규격 ($\pm$10%의 오차)에 만족하는 수치이다.

• Economic and Environmental Geology
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• v.48 no.5
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• pp.391-400
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• 2015

Korea is a global steel producer and a major consumer while iron ore producing is very low compared to the demand. On the other hand, North Korea holds tremendous amount of iron reserves and, however, its producing rate is limited. Moreover, the data regarding mineral resources of North Korea is very limited and uncertain because of political isolation. This study estimated the amount of iron ore resource and production amount for the Musan Iron mine, the world-known open-pit mine of North Korea, using satellite imagery(Landsat MSS, ASTER) and digital maps between 1976 to 2007. As a result, the mining area of Musan mine was increased by $6.1km^2$ during the 30 years and the mining sector was estimated as $4.9km^2$. We estimated the iron resources and production amount of 0.7 and 0.2 billion metric tons, respectively based on 3D modeling and average iron ore density of Anshan formation in China. This amount indicates 8.1 million tons of annual average production and it coincides well with previous reports. We expect this study would be utilized significantly on inter-Korean exchange programs by providing trustable preliminary data.

• Photonics industry news
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• s.4
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• pp.44-47
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• 2001

• Photonics industry news
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• s.12
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• pp.38-43
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• 2002

전세계적인 IT불황에도 불구하고 우리나라 IT수출이 회복세를 보이고 있는 것은 중국 IT산업의 급성장이 크게 기여하였다. 그러나 우리의 최대수요처인 미국의 IT투자가 살아나지 않는 한 이 같은 회복세는 제한적일 수밖에 없을 것이다.

• Photonics industry news
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• s.1
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• pp.61-61
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• 2000

• Photonics industry news
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• s.1
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• pp.63-63
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• 2000