• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.253-255
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• 2004

The mining-related damages such as ground subsidence, acid mine drainage(AMD), and deforestation in the abandoned underground coal mine areas become an object of public concern. Therefore, the system to manage the miningrelated damages is needed for the effective drive of rehabilitation activities. The management system for Abandoned Underground Coal Mine using GIS includes the database about mining record and information associated with the mining-related damages and application programs to support mine damage prevention business. Also, this system would support decision-making policy for rehabilitation and provide basic geological data for regional construction works in abandoned underground coal mine areas.

• Environmental Engineering Research
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• v.23 no.3
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• pp.265-270
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• 2018

This study was to measure the exposure of diesel vehicle drivers to elemental carbon (EC) as an indicator of diesel particulate matter (DPM) emitted from diesel vehicles in an underground coal mine over 3 years as per NIOSH Method 5040. Our study results (range $10{\mu}g/m^3-377{\mu}g/m^3$ for the loader drivers, $19{\mu}g/m^3-162{\mu}g/m^3$ for the SMV drivers) were similar or less than previous study results (range $5{\mu}g/m^3-2,200{\mu}g/m^3$) for normal mine operations. From this study results, it appeared that the exposures decreased in the second and the third year. It is thought that the reasons for the decreased personal DPM (EC) exposures over the 3 years were related to the following recommendations; more frequent monitoring and maintenance of the diesel vehicles and their DPM filtration systems, more consistent monitoring of the mine's ventilation system and changes of work practices such as minimizing the opening of diesel vehicle windows. An educational program on adverse health effects of exposure to DPM and use of respiratory protection (P2 respirators) also assisted in minimizing driver exposure to DPM.

• Safety and Health at Work
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• v.11 no.3
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• pp.322-334
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• 2020

Background: Spontaneous combustion of coal is one of the factors which causes direct or indirect gas and dust explosion, mine fire, the release of toxic gases, loss of reserve, and loss of miners' life. To avoid these incidents, the prediction of spontaneous combustion is essential. The safety of miner's in the mining field can be assured if the prediction of a coal fire is carried out at an early stage. Method: Adularya Underground Coal Mine which is fully mechanized with longwall mining method was selected as a case study area. The data collected for 2017, by sensors from ten gas monitoring stations were used for the simulation and prediction of a coal fire. In this study, the fuzzy logic model is used because of the uncertainties, nonlinearity, and imprecise variables in the data. For coal fire prediction, CO, O₂, N₂, and temperature were used as input variables whereas fire intensity was considered as the output variable.The simulation of the model is carried out using the Mamdani inference system and run by the Fuzzy Logic Toolbox in MATLAB. Results: The results showed that the fuzzy logic system is more reliable in predicting fire intensity with respect to uncertainties and nonlinearities of the data. It also indicates that the 1409 and 610/2B gas station points have a greater chance of causing spontaneous combustion and therefore require a precautional measure. Conclusion: The fuzzy logic model shows higher probability in predicting fire intensity with the simultaneous application of many variables compared with Graham's index.

• Geomechanics and Engineering
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• v.18 no.1
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• pp.21-27
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• 2019

Rockburst disasters pose serious threat to mining safety and underground excavation, especially in China, resulting in massive life-wealth loss and even compulsive closed-down of some coal mines. To investigate the mechanism of rockbursts that occur under a state of static forces, a stress model with sidewall as prototype was developed and verified by a group of laboratory experiments and numerical simulations. In this model, roadway sidewall was simplified as a square plate with axial compression and end (horizontal) restraints. The stress field was solved via the Airy stress function. To track the "closeness degree" of the stress state approaching the yield limit, an unbalanced force F was defined based on the Mohr-Coulomb yield criterion. The distribution of the unbalanced force in the plane model indicated that only the friction angle above a critical value could cause the first failure on the coal in the deeper of the sidewall, inducing the occurrence of rockbursts. The laboratory tests reproduced the rockburst process, which was similar to the prediction from the theoretical model, numerical simulation and some disaster scenes.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.422-425
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• 2003

This study was carried out to apprehend the variation of quality of mine drainage in the abandoned Samtan coal mine. After closure of coal mine, although still pumping, water level in underground was raised to loom and the concentration of some elements such as Fe and Mn was elevated. At present, the worst pollution source in this area is too the acidic leachate drained from uncovered mine waste impoundment. The flow rate of mine drainage from the adit is ave. about 20,000t/d. If water were flooded and deteriorated due to stopping pumping, the impact of the mine drainage on the stream around the abandoned mine would be more severe. Therefore, It is considered that the prediction of water quality of mine drainage from the adit after stopping pumping will be very important with a view to establishing countermeasures.

• Proceedings of the KSRS Conference
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• v.2
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• pp.728-731
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• 2006

Ground subsidence near abandoned underground coal mines has become a serious social problem in Korea. The purpose of this study is to perform a comparative analysis between the ground subsidence area and the electrical resistivity measured by field survey at Samcheok City. A raster database composed of ground subsidence areas and electrical resistivity data was constructed for GIS. To analyze correlation between the two constructed raster datasets, we used a frequency ratio model. The results show that low and high electrical resistivity anomaly zones coincide with the existing subsidence areas. We infer that the high anomaly zone means saturated and low anomaly zone means vacant. It suggests that electrical resistivity might be a useful factor for analyzing ground subsidence hazard zone.

• Tunnel and Underground Space
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• v.22 no.6
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• pp.373-382
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• 2012

Cessation of dewatering usually results in groundwater rebound after closing an underground coal mine because the mine voids and surrounding strata flood up to the levels of decant points such as shafts and drifts. Several numerical models have been developed to predict the timing, magnitude and location of discharges resulting from groundwater rebound. This study reviews the numerical models such as VSS-NET, GRAM and MODFLOW, and compares their scopes of assessment at different spatial and time scales. In particular, the GRAM model was reviewed in details to implement it. This paper describes the implementation of GRAM model and its application to the Dongwon coal mine in Korea. The application showed that the groundwater level modeled at the shaft of Dongwon coal mine using the GRAM model is similar to the observed one in the field.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.325-328
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• 2005

To estimate presumptive local ground subsidence area near Abandoned Under ground Coal Mine(AUCM) at Samcheok city in Korea, the geological properties of existing ground subsidence area and the geophysical prospecting data were analyzed using GIS. The electrical resistivity survey and seismic reflection survey database were constructed from investigation reports and factors which are related with ground subsidence such as geological map, topological map, land use map, lineament map, groundwater level, RMR (Rock Mass Rating), mining tunnel map and slope database were constructed also to make a comparative study of each parameters. As a result of the spatial analysis of existing ground subsidence area, 9 major factors causing ground subsidence were extracted and a connection between the structure of underground and the ground subsidence was determined from the analysis of geophysical prospecting data. The estimation of presumptive ground subsidence area was performed using the correlation between the result from neural network analysis of 9 factors and the scrutiny of geophysical prospecting data.

• Proceedings of the KSRS Conference
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• v.2
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• pp.717-720
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• 2006

In this study, we predicted locations vulnerable to ground subsidence hazard using fuzzy logic and geographic information system (GIS). Test was carried out at an abandoned underground coal mine in Samcheok City, Korea. Estimation of relative ratings of eight major factors influencing subsidence and determination of effective fuzzy operators are presented. Eight major factors causing ground subsidence were extracted and constructed as a spatial database using the spatial analysis and the probability analysis functions. The eight factors include geology, slope, landuse, depth of mined tunnel, distance from mined tunnel, RMR, permeability, and depth of ground water. A frequency ratio model was applied to calculate relative rating of each factor, and the ratings were integrated using fuzzy membership function and five different fuzzy operators to produce a ground subsidence susceptibility map. The ground subsidence susceptibility map was verified by comparing it with the existing ground subsidences. The obtained susceptibility map well agreed with the actual ground subsidence areas. Especially, ${\gamma}-operator$ and algebraic product operator were the most effective among the tested fuzzy operators.

• Tunnel and Underground Space
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• v.22 no.6
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• pp.449-461
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• 2012

Coal ash generated from thermal power plants is planned to use for mine filling in order to prevent subsidence of the ground. In according, the basic physical properties and flow characteristics were grasped using coal ash from generated Yeongdong thermal power plant, and hydraulic filling experiments were performed a total of eight times by manufacturing the model of 1 inclined shaft in Hanbo coal mine. The specific gravity of coal ash is 2.34, and the result of particle size analysis belongs to silty sand (SM). Coal ash of weight ratio of 60% was used in the filling experiments of the model, since liquefaction have shown in coal ash less than weight ratio of 70% from the result of slump and flow test. The outlet should be located at the bottom of the inclined and vertical shaft, this was favorable way in improving the filling efficiency from the experiment results regardless of groundwater exists.