• Proceedings of the Korean Geotechical Society Conference
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• 2006.10a
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• pp.66-75
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• 2006

As construction for road tunnel is increasing, various geotechnical conditions can be faced during the construction stage. Especially, if the tunnel is located in limestone area, many kinds of site investigations such as in-situ boring, electrical resistance survey, TSP(Tunnel Seismic Prediction) and etc., are conducted before and during the construction. By conducting these preliminary tests, location, size, and filling materials in limestone cavities can be approximately estimated. Once some cavities which can be harmful for tunnel safety are predicted, methods for ground reinforcement and tunnel excavation, corresponding those ground conditions, have to be established and verified by measurement data and numerical analysis. If necessary, invert lining should be also considered. In this paper, by studying some cases of tunnels constructed in limestone area, predicted problems during construction and rational countermeasures for those are presented.

• Proceedings of the KSRS Conference
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• v.2
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• pp.710-712
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• 2006

The aim of this study was to analyze limestone deposits potential using an artificial neural network and a Geographic Information System (GIS) environment to identify areas that have not been subjected to the same degree of exploration. For this, a variety of spatial geological data were compiled, evaluated and integrated to produce a map of potential deposits in the Gangreung area, Korea. A spatial database considering deposit, topographic, geologic, geophysical and geochemical data was constructed for the study area using a GIS. The factors relating to 44 limestone deposits were the geological data, geochemical data and geophysical data. These factors were used with an artificial neural network to analyze mineral potential. Each factor’s weight was determined by the back-propagation training method. Training area was applied to analyze and verify the effect of training. Then the mineral deposit potential indices were calculated using the trained back-propagation weights, and potential map was constructed from GIS data. The mineral potential map was then verified by comparison with the known mineral deposit areas. The verification result gave accuracy of 87.31% for training area.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.3 no.3
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• pp.189-196
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• 1999

The community structure, phytomass, and primary productivity in Thuja orientalis stands on a limestone area located in Maepo-up, Chungbuk province in Korea were estimated quantitatively. Seven species including a small proportion of Quercus dentata were identified in the tree layer, 26 species including Ulmus macrocarpa in the shrub layer, and 79 species including Carex lnceolata in the herb layer of the Thuja stands. The vertical distribution of the fine root phytomass exhibited a power functional decrease relative to the soil depth. The seasonal changes in the fine root phytomass at a soil depth of 5 cm were closely related to the pecipitation in the study area. The productivity of the stand of stems, branches, leaves, and roots were 10.72, 0.82, 0.45 and 6.46 ton DM. $ha^{-1}$ .$yr^{-1}$, respectively. The Thuja stand had a high foliage(25%) and low rate of production per unit of foliage. The annual turnover rate of the fine roots int he Thuja stand was 6.71 $yr^{-1}$. The net primary production of the overstory including the understory was estimated at 19.48 ton DM.$ha^{-1}$.$yr^{-1}$ including an underground section of 6.46 ton DM.$ha^{-1}$.$yr^{-1}$(33%). The allocation ratio of net production to root was lower in the limestone Thuja communities than at the nearby non-limestone ones, whereas the production efficiency to leaf weight was higher in the limestone communities. These results would seem to indicate that the limited production capacity is due to the calcium toxicity and low availability of iron and phosphorus in a limestone soil with a high pH, calcium, and bicarbonate content with a strategy for survival in a hostile habitat.

• Journal of Environmental Impact Assessment
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• v.23 no.1
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• pp.1-9
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• 2014

This study, focusing on the area expansion of limestone mines, identifies the problems of Environmental Impact Assessment(EIA) and what impact the current problems exert on another mines developing process. The legal relations analysis reveals that the Management of Mountainous Districts Act and other related laws effect on EIA process, especially the case of area expansion of limestone mines excluded from EIA. However, these problems can create mismatch with the policy goal of EIA system and have a negative impact on the environment in the future. A series of indepth interviews with managers in related agencies found that those agencies have been unaware of the seriousness of the problem. Without any strategy, negative result made by development activities would get more serious and sustainable development may not be possible at all. In order to solve these problems, government should modify the current interdependent legal provision and create the incentive structure to participate actively related agency in the EIA system.

• The Journal of the Petrological Society of Korea
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• v.16 no.2 s.48
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• pp.47-58
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• 2007

This study examines the distribution of basement rocks in Gyochon-ri, Muan-eup, Muan-gun, Jeonnam where ground subsidence occurred in June 2005, and traces corrosion of limestone. Mica schist and rhyolite are distributed in the surface of the study area, but thick limestone layer with large and small caverns are distributed underground. A horizon of limestone with maximum width of 300 m and 4 km of length was found along the detour which is in the north of pound subsidence. Such identification of limestone presence would be very useful to predict potential ground subsidence. Limestone in this area was disturbed by fold and fault due to severe shearing deformation. Small caverns were frequently found in anticline part of folds formed in limestone layer. Schists with different thicknesses were intercalated in the limestone with shearing deformation and consist of sheet silicate minerals (chlorite and mica) and quartz. In sections of weathered specimen, it is shown that biotite of schist part was altered into chlorite and corrosion of calcite around the schist followed. This suggest that ground water permeated between intercalated sheet silicate minerals and corrosion of limestone began. And small caverns were generated where active corrosion occurred. This study suggests that because of many reasons (for instance, reclamation of the Bulmu reservior and excess pumping), cavern water level was lowered and cave sediments were removed, and it caused ground subsidence to occur.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.05a
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• pp.72-72
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• 2000

• Clean Technology
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• v.3 no.1
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• pp.106-113
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• 1997

The objectives of this study were to investigate the characteristics of limestone calcination and sulfation in a fluidized bed reactor with bed temperature and air velocity. The experimental results were presented as follows ; First, the bed temperature had a great influence on the calcination and the sulphur retention of limestone and paper sludge. In paper sludge, the optimum conditions in calcination and desulfurization temperature was at $800^{\circ}C$ and in natural limestone, that was at $850^{\circ}C$ or $900^{\circ}C$. Second, as air velocity increased, the specific surface area of particles decreased. But the difference of surface area according to air velocity was not too large. The specific surface area of paper sludge was larger than that of natural limestone. Third, as air velocity increased, the absorbed amount of sulfur dioxide decreased. And the absorbed amount of sulfur dioxide by paper sludge was larger than that of by natural limestone. Therefore, we knew that paper sludge was excellent absorbent and bed temperature had a great important variable on the calcination and sulphur retention in a fluidized bed.

• Resources Recycling
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• v.33 no.1
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• pp.69-76
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• 2024

In an effort to achieve the goal of carbon neutrality, countries around the world are aiming to phase out coal-fired power plants. Due to various reasons, electricity production through coal-fired power generation and sulfur oxide (SOx) emissions are expected to continue in the future. In the South Korea, sodium bicarbonate (NaHCO₃) and lime materials are used to treat SOx, and most of the sodium bicarbonate is imported. Therefore, this research was conducted to replace sodium bicarbonate by improving the physical properties of lime materials using domestic limestone. Limestone was heat-treated through a box-type electric furnace and a vertical electric furnace. Due to the structural characteristics of the vertical electric furnace, a lime material(quicklime) was possible to improve the physical properties like a specific surface area and a pore volume. Then, they were reached to 22.33 m²/g specific area and 0.14 cc/g pore volume.

• Journal of the Korean earth science society
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• v.27 no.7
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• pp.768-777
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• 2006

The goal of this study is to elucidate the fusulinid biostratigraphy of the Carboniferous limestones distributed in the Gangdong area of Samcheok coalfield, Korea. The Carboniferous strata of the study area mainly comprise alternaton of dark gray shale, dark gray and reddish sandstone, and gray limestone. The limestones consist mainly of wackestonepackstone containing various fossil fragments such as crinoid, coral, brachiopod, foraminifera, fusulinid, and bryozoa; this observation thus suggests that the study site was the shallow marine environments. A tital of 12 species belonging to 5 genera of fusulinids are identified from the limestones of the Gangdong geologic section: Ozawainella turgida Sheng, Ozawainella sp. A, Ozawainella magna Sheng, Pseudostaffella antiqua (Dutkevich), Pseudostaffella paracompressa Safonova, Pseudostaffella kimi Cheong, Pseudostaffella sp., Beedeina lanceolata (Lee and Chen), Beedeina samarica (Rauser-Chernoussova), Beedeina sp. A, Neostaffella sphaeroidea cuboides Rauser-Chernoussova, and Hanostaffella hanensis Cheong. Such fusulinids species were reported from the lower part of the Geumcheon Formation in Samcheok coalfield and the middle Moscovian stage in Eurasia. On the basis of the fusulinid biostratigraphic correlation of the Gangdong geologic sections (A) to (C), the limestone should be overlapped by faults and folds. Moreover the stratigraphic thickness of the limestone is thinner than the thickness of the limestone outcrop of the Gangdong geologic section. Therefore, the stratigraphic sequence of the Gangdong geologic section is represented as the Gangdong geologic section (A).

• Journal of the Korean earth science society
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• v.23 no.6
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• pp.486-493
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• 2002

Hydrogeochemical characteristics of groundwater from a limestone and granite area were studied in the Hwanggangri district, where important fluorite ore deposits are distributed. The geochemical properties of groundwater from limestone and granite are commonly characterized as Ca$^{2+}$-HCO$_3\;^-$ and (Ca$^{2+}$+Na$^+$)-HCO$_3\;^-$ type, respectively. Groundwater, contaminated by mine drainage water from the neighboring ore deposits, has not been observed yet. However, fluoride in groundwater exceeding the drinking water permission level is found in the wells located in a Cretaceous granite area. The concentrations of F in the groundwater show a positive relationship with the values of Na, HCO$_3$, Li and pH. This may suggest that the groundwater come from the decomposition of fluoride-bearing silicate minerals within highly differentiated granitic rocks.