• Economic and Environmental Geology
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• v.55 no.3
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• pp.241-259
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• 2022

In general, the REE were produced by mining conventional deposits, such as the carbonatite or the clay-hosted REE deposits. However, because of the recent demand increase for REE in modern industries, unconventional REE deposits emerged as a necessary research topic. Among the unconventional REE recovery methods, the REE-bearing coal deposits are recently receiving attentions. R-types generally have detrital originations from the bauxite deposits, and show LREE enriched REE patterns. Tuffaceous-types are formed by syngenetic volcanic activities and following input of volcanic ash into the basin. This type shows specific occurrence of the detrital volcanic ash-driven minerals and the authigenic phosphorous minerals focused at narrow horizon between coal seams and tonstein layers. REE patterns of tuffaceous-types show flat shape in general. Hydrothermal-types can be formed by epigenetic inflow of REE originated from granitic intrusions. Occurrence of the authigenic halogen-bearing phosphorous minerals and the water-bearing minerals are the specific characteristics of this type. They generally show HREE enriched REE patterns. Each type of REE-bearing coal deposits may occur by independent genesis, but most of REE-bearing coal deposits with high REE concentrations have multiple genesis. For the case of the US, the rare earth oxides (REO) with high purity has been produced from REE-bearing coals and their byproducts in pilot plants from 2018. Their goal is to supply about 7% of national REE demand. For the coal deposits in Korea, lignite layers found in Gyungju-Yeongil coal fields shows coexistence of tuff layers and coal seams. They are also based in Tertiary basins, and low affection from compaction and coalification might resulted into high-REE tuffaceous-type coal deposits. Thus, detailed geologic researches and explorations for domestic coal deposits are required.

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.223-225
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• 2003

충북 보은군 회남면 조곡리와 분저리 일대에는 옥천누층군의 변성퇴적암에 속하는 문주리층, 창리층, 황강리층 및 국사봉층이 분포한다. 특히 국사봉층에는 모암의 주향연장을 따라 3～6매의 저품위 탄층이 단속적으로 배태되어 있어, 이를 대상으로 개발되었던 한도탄광, 부국탄광, 삼성제일탄광 및 보은제일탄광이 있다. 각각의 탄광주변에는 탄층을 따라 노두의 여러 곳에 갱도와 지표 채굴적이 산재한다. 노두에서 관찰되는 탄층은 수직 20 m 내외에서 10～300 cm의 폭을 보이나 대부분 100 cm 미만이다. (중략)

• Journal of the Mineralogical Society of Korea
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• v.19 no.3 s.49
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• pp.197-207
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• 2006

In the coal-bearing formations of the Janggi Group, which are reported as typical clastic sediments, several beds of volcaniclastic rocks are actually found in the Yeongil area. The coal-bearing formations generally exhibit alternating lithologic characteristics of pyroclastic and epiclastic sedimentary facies. Tuff and tuffaceous sandstone rich in pumice fragments are characteristic in the coal-bearing fermations. Diagenetic minerals found in the pyroclastic rocks of the upper and lower coal-bearing formations are montmorillonite, clinoptilolite, opal-CT, and quartz. Several tuffaceous beds correspond to the low-grade ores of zeolites and bentonite, and moreover, these ores mostly occur as thin beds less than 1 m in thickness. Thus, the potential of altered tuffaceous rocks as the resources typical of zeolite and bentonite seems to be low. However, based on mineral composition and CEC determinations, it can be evaluated that these tuffaceous rocks mostly have the promising potential for utilization as the absorbent-functional mineral resources such as acid clays, if these low-grade ores plus adjacent tuffaceous rocks are collectively exploited.

• Economic and Environmental Geology
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• v.55 no.2
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• pp.149-169
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• 2022

Indonesia coal is widely consumed as a major energy source in Asian countries, such as China, India, and Korea. In the paper, the characteristics of the coal-bearing basin and coal deposits in Indonesia are comprehensively reviewed using the exploration data accumulated through the coal exploration projects supported by Korean government subsidy. Cenozoic coal bearing sedimentary basins in Indonesia extensively contain coal deposits and are most productive in East Asia. Properties of coal deposits are variable depending on stratigraphy, depositional histories and tectonics. Eocene coal deposits tend to have thinner coal thickness and fewer numbers of coal seams, but have been major exploration targets due to higher calorific value and good coal quality. Late Oligocene-Early Miocene coal deposits occur in small scales, but are suitable enough for small to medium-sized coal mines. Miocene-Pliocene coal deposits, which are widely distributed across East Kalimantan and Sumatra, are being actively mined by taking advantage of thick coal thickness and abundant reserves in spite of their lower calorific values. The experience of various exploration informs that we need to have an overall understanding on geological conditions for successful coal exploration. The details on coal-bearing basin and coal deposits in Indonesia provided through the paper will be useful data for up-coming exploration activities by Korean companies.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2008.11a
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• pp.124-126
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• 2008

활성탄 흡착설비에서는 활성탄에 대한 차압특성 및 활성탄 층에서의 적절한 유동분포가 이루어져야 활성탄층에서의 고른 흡착분포를 보이게 된다. 즉, 흡착설비로 주입된 VOCs 가스는 활성탄층를 통과할 때 활성탄층 전 영역에서 고르게 유량이 분배되면서 통과를 해야만 활성탄의 파과시간과 교체주기가 같게 된다. 따라서 고안된 활성탄 카트리지 및 흡착설비가 이러한 고른 유동분포를 갖는지를 먼저 해석하였다. 본 연구에서는 기존에 VOCs 흡착제로 쓰이고 있는 활성탄에 대한 차압특성을 알아보고 차압에 따른 유동장을 해석하여 유입된 VOCS를 포함한 오염가스가 활성탄층에 고르게 분포되는가를 해석하였다. 이러한 결과를 토대 활성탄 카트리지내의 구조에 따른 활성탄의 높이 및 양을 제시하였다.

• Journal of the Korean earth science society
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• v.31 no.6
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• pp.573-583
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• 2010

A paleobotanical study of the fossil woods has been carried out from the Tertiary Janggi Group, Pohang Basin. Three species belonging to three genera of Ulmus sp., Prunus sp., and Acer sp. were identified from the Lower Coalbearing Formation, and two species of two genera of Taxodioxylon sp. and Fagus hondoensis (Watari) from the Upper Coal-bearing Formation. As our specimens are mostly poorly preserved, it is difficult to give clear specific names, but mostly are all characteristic constitutional elements of the Miocene fossil woods in Korea. The values of mean sensitivity measured from the fossil woods of Lower and Upper Coal-bearing Formations are 0.367 and 0.370 respectively, but they are more than 0.30. Based on the present two data mentioned above, it stands to reason that there were many changes in the water supply to the roots of the woods or having influence to some degree each year because of the seasonal changes in rainfall.

• Journal of Korean Tunnelling and Underground Space Association
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• v.4 no.2
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• pp.155-165
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• 2002

This paper presents a case study on the construction of a long tunnel named as "Solan tunnel", which connects between Mt. Dongbaek station and Dokye station in the Youngdong Railroad. The tunnel will be the longest tunnel with length of 16.4 km in Korea when completed. The tunnel site is located in a complex geological region with faults, cavities and coal measures. In construction of adit No. 2, geophysical investigation methods such as electrical resistivity method and GPR(Ground Penetration Radar) were used to detect faults, cavities and coal measures in advance with some success. The geophysical investigation results and in-situ boring data were used as feedback to improve tunnel reinforcement design. Also, the tube umbrellas of grouted steel pipes were found to have a good reinforcement and grouting effects in zones of faults, cavities. In zones of coal measures, swellex rockbolts with mortar grouting were verified as successful.

• 한국지구물리탐사학회:학술대회논문집
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• 2000.09a
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• pp.87-111
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• 2000

In this study, we describe the principle and result of geophysical techniques which are widely used in geotechnical survey. Also we discuss two case histories. One is discrimination of limestone cavity areas by resistivity, seismic tomography, televiewer, well logging, and the other is discrimination of coal by resistivity, electromagnetic method, resistivity tomography.

• Journal of Wetlands Research
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• v.9 no.3
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• pp.1-12
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• 2007

In this study, the correlation of organic content with particle size and type of sediment was found out.Particle size, stratigraphic section and organic content of sediments sampled from Dalpo wetland was analyzed. Dalpo wetland consists of three wetlands, and the area of Dalpo wetland is about $31,295m^2$. The particle size analyses for sampled sediments of 7 points (3 points in wetland A, 3 points in wetland B and 1 point in wetland C) were tested. As results of the particle size analyses, the sediment particle size becomes larger as to the edge of the wetland. It is revealed in order of wetland A > wetland C > wetland B. Borehole surveys with horizontal distance in the major and minor axes of wetland A, the major and minor axes of wetland B and the major axis of wetland C were accomplished. Clayey peat deposit is distributed at 10~90 cm depth below ground surface in the major axis of wetland A. The clayey peat deposit was the most thick at the center of wetland A that horizontal distance is 100 m. As the depth below ground surface of clayey peat deposit is less than 27 cm in the wetland B, we can infer that the life for the wetland B is being finished. Sediment composition of wetland C is simple because wetland C is small scale, and clayey peat deposit is distributed at 10~34 cm depth below ground surface. Sediment sampled by borehole survey in the Dalpo wetland was cut at interval of 10 cm, then organic content was analyzed. Organic content of wetland A sediment showed more than 40% until 70 cm depth below ground surface, also sediment of wetland B is similar to wetland A until 10 cm depth below ground surface, but is showed within 20 % above 30 cm depth below ground surface. Organic content of wetland B is showed the lowest as organic content near the ground surface is about 40%. All of the three wetlands, organic content is showed higher at clayey peat deposit near to ground surface. This is caused by finer particles of the clayey peat deposit, also organic materials were supplied from dead vegetation. Organic content of the Dalpo wetland showed in order of wetland A > wetland C > wetland B. This result is caused by thickness of clayey peat deposit in sediment. Through this study, it was verified that organic content of the Dalpo wetland sediment was dominated by particle size of sediment and vegetation of the upper part.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2006.04a
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• pp.517-518
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• 2006