• The Journal of Engineering Geology
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• v.28 no.4
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• pp.701-714
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• 2018

The purpose of this study is to show the possibility of 3-dimensional modeling of open-pit limestone mine by using a rotary-wing unmanned aerial vehicle, a drone, and to estimate the amount of mining before and after mining of limestone by explosive blasting. Analysis of the image duplication of the mine has shown that it is possible to achieve high image quality. Analysis of each axis error at the shooting position after analyzing the distortions through camera calibration was shown the allowable range. As a result of estimating the amount of mining before and after explosive blasting, it was possible to estimate the amount of mining of a wide range quickly and accurately in a relatively short time. In conclusion, it is considered that the drone of a rotary-wing unmanned aerial vehicle can be usefully used for the monitoring of open-pit limestone mines and the estimation of the amount of mining. Furthermore, it is expected that this method will be utilized for periodic monitoring of construction sites and road slopes as well as open-pit mines in the future.

• Tunnel and Underground Space
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• v.17 no.4
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• pp.255-265
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• 2007

As the mechanism and effect range of subsidence are altered according to the various conditions (the ground condition, the earth pressure, the geometric condition of underground cavity and the structure load), the analysis and prediction of subsidence in abandoned mining area are very difficult. Also, as the geological characteristics and the mining methods are differed in each mines, the application of the pre-existing reinforcements without improvement has a lot of difficulties and limits. In this study, the various underground investigation such as long-depth core drilling, seismic tomography and BIPS (borehole image processing system) were performed, the distribution of underground cavity and coal seam and rock relaxation condition were analyzed. And we predicted the type of subsidence and estimated the subsidence by theories of mining subsidence. With these results, we analyzed the mechanism of subsidence occurrence in the research object area. Finally, we improved existing methods which were applied to the abandoned mining area and also we established the rational reinforcement for the ground and structure foundation against each subsidence cause.

• Environmental and Resource Economics Review
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• v.15 no.4
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• pp.673-692
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• 2006

In order to test for the dynamic optimality condition for the use of nonrenewable resource, it is necessary to estimate the shadow value of the resource in situ. In the previous literatures, a time series for in situ price has been derived either as the difference between marginal revenue and marginal cost or by differentiating with respect to the quantity of ore extracted the restricted cost function in which the quantity of ore is quasi-fixed. However, not only inconsistent estimates are likely to be generated due to the nonmalleability of capital, but the estimate of marginal revenue will be affected by market power. Since firms will likely fail to minimize the cost of the reproducible inputs subject to market prices under realistic circumstances where imperfect factor markets, strikes, or government regulations are present, the shadow in situ values obtained by estimating the restricted cost function can be biased. This paper provides a valid methodology for checking the dynamic optimality condition for a nonrenewable resource by using the input distance function. Our methodology has some advantages over previous ones: only data on quantities of inputs and outputs are required; nor is the maintained hypothesis of cost minimization required; adoption of linear programming enables us to circumvent autocorrelated errors problem caused by use of time series or panel data. The dynamic optimality condition for domestic coal mining does not hold for constant discount rates ranging from 2 to 20 percent over the period 1970~1993. The dynamic optimality condition also does not hold for variable rates ranging from fourth to four times the real interest rate.

• Environmental and Resource Economics Review
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• v.25 no.2
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• pp.255-276
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• 2016

This paper is designed to investigate the dynamic structure of optimal tariff imposed by the oil importing country from OPEC when OPEC increases the oil reserves through exploration and development. For this purpose, we used a Stckelberg differential game modeling approach, and tried to analyze two cases such that the one is the extraction cost is dependent on the oil reserves and the other is the extraction cost is independent of it. On the basis of this analysis, we propose that the importing contry has to impose dynamically inconsistent tariffs if the extraction cost is dependent on the oil reserves. Otherwise, she should impose dynamically consistent tariffs announced at initial time. In addition, we found that whether or not the exporting country uses some portion of oil produced for domestic consumption does not affect our policy proposition stated above.

• Tunnel and Underground Space
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• v.18 no.6
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• pp.436-446
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• 2008

The volumetric expansion ratio of rock mass on the subsidence occurrence area can explain why the depth of the surface subsidence is lower than the height of an opening; it is because the empty space of the gangway is filled with the broken rock. But, until now, when the surface subsidence mechanism is studied without consideration of the volumetric expansion ratio, it is usually overlooked that the amount of subsidence occurrence can be overestimated. Therefore, in this study, the authors researched the subsidence occurrence mechanism with a new theoretical approaching method. The volumetric expansion ratio obtained from this method has been applied to the numerical simulations. The authors adopted the UDEC(Universal Distinct Element Code) for their discontinuum numerical analysis, because this program has an advantage for analyzing the behavior of rock discontinuities.

• Journal of the Korean GEO-environmental Society
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• v.4 no.2
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• pp.15-25
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• 2003

Time Domain Refletometry, or TDR, is a remote sensing electrical measurement technique that has been used for many years to determine the spatial location and nature of various objects, especially in the United States of America and Australia at mining industry. Since early on 1990, the TDR techniques have been applied to the geotechnical engineering such as : deformation measurement of rock slope and landslide, monitoring of ground water content and ground water level change, investigation of ground contamination and its movement. The first application of this technique, in 1996, to the domestic area is to determine the possibility of ground settlement caused by subsidence from abandoned underground mines at the Tongri and Gosari in Gangwon-d. In this paper, through the results of analysed deformation data between conventional measurements and the TDR, it was concluded that the TDR technique is a useful instrumentation method for the prediction of ground deformation.

• Economic and Environmental Geology
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• v.46 no.4
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• pp.351-358
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• 2013

Methane burns more clearly than any other fossil fuels. Coalbed methane(CBM) is natural gas contained in coal beds. This gas is usually producted from coal that is either too deep or too poor-quality to be mined commercially. While global coalbed methane resource estimates are rough, they indicate between 84 and 377tcm, which compares with proven natural gas reserves of 180tcm. Coalbed methane resources are currently only produced on a major scale in the United States, Canada, Australia and China. In this study, we analysed total 109 published papers for the CBM during the 1990~2012 periods by the programs of 'web of science'. The results of analysis, the CBM study led by the United States, the follow India and Australia. In subject area(web of sciences), Energy Fuels is 57, Engineering 58 and Geology 41 papers, respectively.

• 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.

• Geophysics and Geophysical Exploration
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• v.4 no.4
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• pp.101-109
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• 2001

In order to develop a spatial information system that can efficiently manage various subsurface data and produce information in a proper form for a user, we established a database of the well cores and built 3-D shapes that visualize the subsurface objects such as wells, ore bodies, tunnels, and mine cavities. We also made analysis tools available for three-dimensional ore bodies constructed here, such as vertical cross-section generator and mass computing tool. This system was developed by coding Avenue, a scripting language incorporated in ArcView, which is a commercial GIS software. Using the system, it is expected that users can make fast and accurate analysis and interpretation through real-time queries and by contemplating various objects in 3-D perspective.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.870-870
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• 2013

운송수단은 시대별로 요구되는 성능과 기술 수준 그리고 사용 가능한 에너지의 형태에 따라서 변화되어 왔습니다. 1900년대 초 전기자동차의 고질적인 제한적 운행 거리 문제는 내연기관의 발명으로 인해서 쉽게 해결되었다. 이 후 내연기관의 급속한 보급과 도심 과밀화로 인해서 공해 문제가 대두되었는데, 공해 문제 역시 배기 가스 환원 촉매의 발달과 자동차 전자 제어 기술의 발달로 대부분 해결된 상태이다. 최근에는 사용 가능한 화석에너지의 절대량 측면에서 하나의 커다란 시대적 전환점에 서게 되었다. 즉 아직도 사용 가능한 석유의 절대적인 양적 측면에서는 적당한 공급이 이루어지고 있으나 그 가격 면에서는 급격한 상승이 이어지고 있으며 이는 석유의 채굴이 점점 어려워지고 있음에 기인한다. 에너지의 현황을 객관적으로 살펴 보기 위해서 자동차에 있어서 절대적인 오일을 중심으로 그리고 통계자료 위주로 문제를 분석해 본다. 그리고 수소 연료 전지와 전기자동차 등 여러 가지 대체 에너지 운송기술이 많이 거론되고 있으나 널리 대중화 되고 있지 못하는 근본적인 문제점들이 어디에 있는지 분석해 본다. 이어서 소위 대체 에너지들이 자동차에 있어서 석유의 대체 수단으로 적합하지 않다면 과연 에너지를 가장 많이 쓰는 영역중의 하나인 운송 분야의 현재와 미래의 나아갈 방향은 무엇인지 그 해법을 생각해 본다. 석유를 대체할 에너지의 공급 방안이 충분하지 않다면 마지막으로 생각할 수 있는 것은 에너지의 소비 측면이다. 다행히도 그간 소비 측면의 개선 방안이 많이 소홀하게 취급되어져 왔다. 즉 에너지의 효율을 향상시킬 수 있는 여력이 충분하고도 많이 있다는 희망적인 소식이다. 이에 따라 에너지 효율 향상에 유용하게 사용할 수 있는 다양한 제어 기술을 소개한다. 에너지와 운송수단의 문제를 거시적이고 동시에 현실적으로 바라볼 수 있는 안목을 갖게 되기를 기대한다.