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

• Journal of the Korean earth science society
• /
• v.34 no.3
• /
• pp.195-208
• /
• 2013

We employed electrical resistivity and optical borehole imaging methods to identify underground cavities and determine ground subsidence rate at the study area affected by land subsidence due to abandoned underground mines. At the study site 1, the anomalous zones of low resistivity ranging between 100 ohm-meter and 150 ohm-meter were observed and confirmed as an abandoned underground mine by subsequent borehole drilling and optical borehole imaging. Although the electrical resistivity survey was unavailable due to the paved surface of the study site 2, we were able to locate another abandoned underground mine with the collapsed mine shaft based on the distribution of the ore veins and confirmed it with borehole drilling. In addition, we measured vertical displacements of underground features indicating underground subsidence by conducting optical borehole imaging 6 times over a period of 43 days at the study site 2. The displacement magnitude at the deep segment caused by subsidence appeared to be 3 times larger than those at the shallow segment. Similarly, the displacement duration at the deep segment was 4 times longer than those at the shallow segment. Therefore, the combination of electrical resistivity and optical borehole imaging methods can be effectively applicable to detect and monitor ground subsidence caused by underground cavities.

• Tunnel and Underground Space
• /
• v.24 no.6
• /
• pp.449-463
• /
• 2014

There are many case studies and application cases in abandoned mines for hydraulic filling method filled by slurry or paste form, but research on the pneumatic filling is not applied in Korea. The damage of steel pipe is occurred by wear due to the flow of filling material in the bent area of steel pipe in traditional pneumatic filling method. In this study, the new pneumatic filling method was developed using a newly devised improved nozzle to improve the above problem. The model test for mine filling was performed in the laboratory for the simulated accessible or inaccessible mine cavities, and the filling efficiency by the results obtained from the test was calculated. The filling efficiency was analyzed from the variation of outlet angle, feed rate and grain size of sand in model test of simulated accessible mine cavity. The superiority of improved pneumatic filling method was proved through the analysis of filling efficiency by the results obtained from each model tests of gravitational, traditional, and improved filling method in simulated inaccessible mine cavity.

• Economic and Environmental Geology
• /
• v.53 no.3
• /
• pp.287-296
• /
• 2020

Mine Reclamation Project is being carried out with the aim of ensuring a sustainable green living and helping to develop eco-friendly mines by analyzing, removing and preventing the harmful factors. Mines developed during the japanese colonial period and mining boom period are still not repaired throughout the country, and from these scattered risks, public safety is worth pursuing as a top priority. The project that is close to public safety in the mine recalmation project is an emergency treatment, and the most widely used method is a filling method similar to the ground subsidence prevention. If dangerous mine cavity or tunnels are located in the mountains, charging with existing materials may not be possible, or unreasonable cases may occur, and new methods of technological development are required. Emergency actions should be carried out safely and efficiently to prevent the loss of precious people's lives on the hiking paths adjacent to dangerous mining sites. In these field conditions, urethane foam materials may be an alternative. In this study, the applicability of urethane foam materials in mining was reviewed through overseas cases. It was also tested on the appropriate depth of top soil for the protection of urethane foam materials through forest fire simulation test. The test result show that approximately 15cm of soil covering (recommended 20cm over) was suitable for maintaining the function of foam materials from forest fires.

• Geophysics and Geophysical Exploration
• /
• v.1 no.1
• /
• pp.25-30
• /
• 1998

Time-lapse crosswell seismic data, recorded before and after the cavity filling, showed that the filling increased the velocity at a known cavity zone in an old mine site in Inchon area. The seismic response depicted on the tomogram and in conjunction with the geologic data from drillings imply that the size of the cavity may be either small or filled by debris. In this study, I attempted to evaluate the filling effect by analyzing velocity measured from the time-lapse tomograms. The data acquired by a downhole airgun and 24-channel hydrophone system revealed that there exists measurable amounts of source statics. I presented a methodology to estimate the source statics. The procedure for this method is: 1) examine the source firing-time for each source, and remove the effect of irregular firing time, and 2) estimate the residual statics caused by inaccurate source positioning. This proposed multi-step inversion may reduce high frequency numerical noise and enhance the resolution at the zone of interest. The multi-step inversion with different starting models successfully shows the subtle velocity changes at the small cavity zone. The inversion procedure is: 1) conduct an inversion using regular sized cells, and generate an image of gross velocity structure by applying a 2-D median filter on the resulting tomogram, and 2) construct the starting velocity model by modifying the final velocity model from the first phase. The model was modified so that the zone of interest consists of small-sized grids. The final velocity model developed from the baseline survey was as a starting velocity model on the monitor inversion. Since we expected a velocity change only in the cavity zone, in the monitor inversion, we can significantly reduce the number of model parameters by fixing the model out-side the cavity zone equal to the baseline model.

• Explosives and Blasting
• /
• v.42 no.2
• /
• pp.29-41
• /
• 2024

The increasing demand for metallic minerals due to global growth and the continued exploitation of near-surface minerals requires safe and efficient ways to mine ores present in deep mines. In deep mines, stresses concentrated around the cavity increase, which can lead to problems such as induced seismicity and rockbursts. In addition, the transfer of energy from blasting to deeply located faults can cause fault slip, which can lead to earthquakes, and controlling these events is key to deep mining methods. In this technical report, we will introduce the Underhand Closed Bench (UCB) mining method, which can control possible accidents and increase productivity when mining in deep mines.

• Tunnel and Underground Space
• /
• v.22 no.6
• /
• pp.412-428
• /
• 2012

To achieve mine development, a large amount of data concerned with the geological structure and the ore body had to be investigated and collected through geological survey, drilling and geophysical explorations. In most previous cases, however, the data were usually analyzed two dimensionally and those results showed some limits because of their 2D presentation. Those 2D maps such as geological plane sections or longitudinal sections cause lots of difficulties in understanding the complex geological structure or the feature of ore body in a spatial way. In this study, research area was set on the abandoned Yangyang iron mine in Korea and the Sugaeng ore body within the mine was selected as the research target to design a mine haulage system for reopening. A 3D mine model of this area was tried to be constructed using a 3D modelling software, GEMS. An accurate 3D model including the ore body, the geological structure, the old underground mine drifts and the new mine drifts was constructed under the purpose of reopening of the abandoned iron mine. Especially, mine design for trackless haulage system was conducted. New inclines and drifts were planned and modelled 3 dimensionally considering the utilization of old drifts and shaft. In addition to the 3D modelling, geostatistical technique was adopted to generate a spatial distribution of the ore grade and the rock physical properties. 3D model would be able to contribute in solving problems such as evaluating ore reserves, planning the mine development and additional explorations and changing the development plans, etc.

• Tunnel and Underground Space
• /
• v.31 no.3
• /
• pp.145-166
• /
• 2021

Korea Stress Map database is built by integrating actual data of 1,400 in-situ stress measurements using hydraulic fracturing and overcoring method in South Korea. Korea Stress Map 2020 is presented based on the guideline proposed by World Stress Map Project. As detailed data, stress ratio and maximum horizontal stress direction distribution for each region are also presented. The dominant maximum horizontal stress direction in the Korean Peninsula is from northeast to southeast, and the magnitude of the in-situ stress is relatively distributed. There is some stress heterogeneity caused by local characteristics such as topographical and geological properties. We investigated case studies in which the in-situ stress was affected by mountainous topography, difference in rock quality of fracture zone, presence of mine or underground cavities, and geological structure of fault zone.

• Tunnel and Underground Space
• /
• v.31 no.6
• /
• pp.623-646
• /
• 2021

As the demand for electric power increases with acceleration of electrification at home and abroad, the needs for coal-fired electrical power plant are accordingly increased. However, these coal-fired electrical power plants induce also many environmental problems such as increase of air pollutants, increase of possibility of land contamination by reclamation of coal ash, even though these power plants have a good economical efficiency. In case of a by-product of coal-fired electrical power plants, only 70% of them are recycled and the remaining 30% of by-product are fully buried in surrounding ground. Consequently, this study deals with coal ash backfilling mechanism in abandoned mine openings for the purposes of increasing the coal ash recycling rate as well as securing the mine area stability. In order to analyze the backfill and ground reinforcement by interaction between rock mass and backfills, the copying samples of discontinuous surface with different roughnesses were produced for bond strength tests and direct shear tests. And statistical analysis was also conducted to decide the characteristics of bond and shear behavior with joint roughness and their curing day. Numerical simulations were also analyzed for examining the effect of interface behavior on ground stability.

• The Korean Journal of Air & Space Law and Policy
• /
• v.29 no.1
• /
• pp.161-198
• /
• 2014

The idea of creating an International Space Exploitation Agency (tentative title: hereinafter referred to ISEA) is only my academic and theoretical opinion. It is necessary for us to establish ISEA as an international organization for the efficient and rapid exploitation of natural resources in the moon and other celestial bodies. The creation of ISEA as a new international organization is based on the Article 11, 5 and Article 18 of the 1979 Moon Agreement. In order to create it as a preliminary procedure, it needs to make the Draft for the Convention on the Establishment an ISEA among the space-faring countries. The main contents of this paper is composed of (1) introduction, (2) joint exploitation of the natural resources (Heliumn-3, etc.) in the moon and ISEA, (3) activities for the exploitation of moon and other celestial bodies by the space-faring powers, (4) legal problems and Solution for the exploitation and mining rights of the natural resources in the moon, mars and celestial bodies, (5) procedure of creating an ISEA, (6) the principal points that need to be included in the draft for the ISEA convention, (7) conclusion. The creation of an ISEA would lead to a strengthening of the cooperation among the States deemed essential by the global community towards joint undertakings in space and would act as a catalyst for the efforts on the exploitation of the natural resources moon, mars, Venus, Mercury and other celestial bodies and allow resources, technology, manpower and finances to be centrally managed in an independent fashion to the benefit of the space-faring countries. It is desirable and necessary for us to create ISEA in order to promote cooperation in the field of space policy, law, science technology and industry etc. among the space-faring countries. The creation of the ISEA will be promoted the international cooperation among the space-faring countries in exploration and exploitations of the natural resources in the moon, Mars, Venus, Mercury and other celestial bodies. Finally, it should be noted that the political drive will be necessary not only to set up the organization ISEA, but also study a subsequent measures. It is also necessary for us to create the ISEA in order to develop the space industry, to strengthen friendly relations and to promote research cooperation among the space-faring countries based on the new ideology and creative ideas. If the heads (president or prime minister) of the space super-powers including the UNCOPUOS will be agreed to establish ISEA at a summit conference, 1 believe that it is possible to establish an ISEA in the near future.