• Tunnel and Underground Space
• /
• v.26 no.2
• /
• pp.131-142
• /
• 2016

Investigation for rock joints, inspection for rock core, and laboratory tests for rock specimens, in this study, have been performed for identification of the extent and properties of Excavation Damaged Zone in a underground limestone mine, which plans to enlarge the size of openings to improve the production rate. Properties of EDZ and surrounding rock masses have been used numerically for discontinuum analysis, and it is concluded that the effect of EDZ can be increased with increasing the opening size and a blasting pattern of high precision can be suggested for the counterplan.

• Geophysics and Geophysical Exploration
• /
• v.9 no.1
• /
• pp.37-43
• /
• 2006

In 2006, the Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC) plans to undertake (subject to receiving the necessary approvals) a Pilot program for $CO_2$ storage within a depleted gas reservoir. The Otway Basin Pilot Program (OBPP) aims to demonstrate that subsurface $CO_2$ storage is both economically and environmentally sustainable in Australia. This will be the first $CO_2$ storage program in the world to utilise a depleted gas reservoir and, hence, the experience gained will be a valuable addition to the range of international $CO_2$ storage programs that are underway or being planned. A key component of the OBPP is the design of an appropriate geophysical monitoring strategy that will allow the subsurface migration of the $CO_2$ plume to be tracked and to verify that containment has been successful. This paper presents the results from modelling the predicted gravity response to $CO_2$ injection into the Otway Basin reservoir, where the goal was to determine minimum volumes of $CO_2$ that may be detectable using non-seismic geophysical techniques. Modelling results indicate that gravity measurements at 10 m spacing within the existing observation well and the planned $CO_2$ injection well would provide excellent vertical resolution, even for the smallest $CO_2$ volume modelled (10000 tonnes), but resolving the lateral extent of the plume would not be possible without additional wells at closer spacing.

• Journal of the Korean GEO-environmental Society
• /
• v.14 no.4
• /
• pp.47-52
• /
• 2013

In Korea, the number of mining operations are getting smaller. But buried accidents are on the increase every year. For this reason, it is important to safety management in construction process, especially the worker's safety. In the field of construction needs utilization of integration system according to purpose of utilization, particularly in underground construction sites utilizing is emphasized even more. The current element technologies of location tracking, sensors and wireless communication possible to utilize but it is still difficult to utilization of integration system in construction field because a study is not complete on commercialization and availability. In this study, for real time 3-dimensional management of ubiquitous construction site in ground and underground, measure data using MEMS sensor, EDM and DGPS in 2 test site. Also results were analysed by MATLAB. As a result, error is verification less than 3 meter that possible to distinguish with the naked eye and construct direction of study based on result of former.

• Tunnel and Underground Space
• /
• v.15 no.5 s.58
• /
• pp.369-377
• /
• 2005

The stability of underground openings is a major concern for the safety and productivity of mining operations. Rock mass classification methods provide the basis of many empirical design methods as well as a basis for numerical analysis. Of the many factors which influence the stability of openings, the span of the opening for a given rock mass condition provides an important parameter of design. In this paper, the critical span curves proposed by Lang, the Mathews stability graph method and the modified critical span curve suggested by the authors have been assessed. The modified critical span curve was proposed by using Mathews stability graph method. The modified critical span curve by the author have been used to assess the stability of underground openings in several limestone mines.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.2 no.2
• /
• pp.62-71
• /
• 2000

The abandoned mines causing settlement of the surface above and collapse of the cavities are the major influencing factor on the stability of the nearby underground structures. To prevent the harmful effect, the backfill methods are commonly applied to the cavities although the design criteria and the analysis method are not properly addressed in some cases. An approximate analytical method together with the numerical technique is considered in this study to simulate the gradual deterioration of the rock masses around the cavities and, therefore, the influential zone to the underground structures passing through the cavities. Also considered in this study is the backfill effect on the stability of the rock masses around the cavities. Specifically, the incomplete backfill effect is compared with that of the idealized backfill method by adopting elasto-plastic analysis involving a strain softening material law.

• Tunnel and Underground Space
• /
• v.23 no.1
• /
• pp.31-41
• /
• 2013

Graphical method has been widely applied to the prediction of subsidence area, and is known to have advantages in analysis of trough subsidence which is common in horizontally seamed mine area. However, it is reported that most of the ore bodies in Korea are geologically inclined from sub-horizontal to steep, and therefore, the sinkhole subsidence is frequent in abandoned mine area. For these reasons, it is not to be desired that graphical method is applied for predicting the subsidence occurrence. This paper describes the results of subsidence zone prediction considering the dip direction and the opposite direction of inclined ore bodies from the case studies on the 163 subsidence occurrence regions. The results show also the assumed angle which can define the range of subsidence in the surface area. In conclusion, the limit of this angle is suggested after taking into account the comparison with graphical method and the application to the case histories.

• 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.

• Tunnel and Underground Space
• /
• v.26 no.5
• /
• pp.418-430
• /
• 2016

In this study, experimental study on cement grout materials containing anti-washout admixtures or accelerators in grout column for reinforcement technology in groundwater-saturated mining cavity was conducted. As a result, the cement milk containing anti-washout admixtures was suitable for mixed aggregates, and the cement mortar containing anti-washout admixtures and the cement milk containing accelerators were suitable for crushed stone aggregate in terms of forming grout column. Especially, in the case of crushed stone aggregate injecting the cement milk containing accelerators, the diameter of the grout column was greatest and the void of the crushed stone aggregate was filled with grout materials. Therefore the case of crushed stone aggregate injecting the cement milk containing accelerators is considered for optimal grout materials and aggregate.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2005.05a
• /
• pp.181-186
• /
• 2005

Gravity method produces subsurface density distribution, which is direct information of soundness of basement. Therefore, microgravity is one of the most effective method for detections of limestone cavities, abandoned mine-shafts and other tunnels, The paper show the effectiveness of microgravity by three different field cases.

• Tunnel and Underground Space
• /
• v.19 no.6
• /
• pp.534-544
• /
• 2009

The collapse of the underground cavity can cause the abrupt local subsidence of the ground surface. It can be hazardous to the stability of road and building for human activity. Therefore it is necessary to develop reinforcement methods for the filling of the underground cavity. This study was executed to improve the material quality and systems to fill the calcium-aluminate mineral $(C_{12}A_7)$ environmentally, and minimize the loss of filling materials for the steep underground cavity. Filling material which was developed in this study is composed of rapid hardening material and additives. The developed material had rapid hardening and non-separation ability in the water cavity condition, so it made the effective underground dam in the cavity with prevention of material loss when it was poured in the water cavity. Results of heavy metal leaching test for environmental assessment showed that it was environmentally suiTable material for the filling in the mine cavity.