• Economic and Environmental Geology
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• v.30 no.2
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• pp.105-116
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• 1997

This study is for extent of polluted area by acid mine drainage from the Daeseong coal mine, Keumsan. Black shales of the Changri Formation containing the Daeseong coal mine are geochemically similar to those from the North America as well as Europe. Comparing with geochemical compositions and relative ratios, coal bearing and non-coal bearing soils are similar to the stream sediments influenced and not influnced by the acid mine drainage, respectively. These characteristics suggest that acidification of the soils and of the stream sediments are related to the the coal bearing black shale. Soil waters beneath the coal bearing soil have low pH and high cation contents than those beneath non-coal bearing soil, suggestive of extractions of cations with increasing oxidizations within the soils. Surface waters show that those influenced by the acid mine drainage are low pH, and have high $SO_4{^{2-}}$, $Mg^{2+}$, $Fe^{2+}$, Mn and slightly lower DO, suggesting that heavy pollutions have been progressed in these area. Geochemical comparisons between the polluted surface water and adjacent black shales suggest that pollutions of the surface water are related to the black shales.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.37-47
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• 2004

In Korea, over three hundreds of the coal mines were closed or abandoned due to the depression of the mining industry since the late 1980s. Many of them locate in the steep mountain valleys and the coal mine wastes had been disposed without a proper treatment From these mines, enormous amounts of coal mine overburdens have been abandoned in the slopes and the ample amounts of acid mine drainage (AMD) from either portal or overburdens have been discharging directly to the streams, causing the detrimental effects on soil and water qualities. Objectives of this research were to reclaim the coal mine overburdens using the lime waste cake from the soda ash production by stabilizing the overburden slopes, introducing the vegetation alleviate the environmental problems caused by the closed coal mines. The percentages of the grass distribution ratio (%) and the surface coverage ($\textrm{cm}^2$) in each treatment plot were determined during June to August after seed spraying grasses such as orchard grass (Dactylis glomerata L), Kentucky Bluegrass (Poa pratensis L.) and Eulalia (Miscanthus sinensis Anderss) at the end of May. The grasses covered only 15.5 % of the coal overburden plot at the early stage but the coverage was increased with time to 33% in August. Growth of such grasses was enhanced with the combined treatments of lime waste and topsoil resulting in the increased surface coverage by the grasses. The Increment of the surface coverage from June to August was higher with lime waste treatments. The distribution percentages and surface coverage were highest when the lime wastes were treated at 25 % of the lime requirement. This might be related with the high salt contents in the hire wastes. Results demonstrated that the amounts of lime wastes at 25% of the lime requirement were sufficient for neutralizing the acidic coal overburden and introducing the re-vegetation. Either layering between the coal waste and topsoil or mixing with coal overburdens could be adopted as the lime waste treatment method. The combined treatment of lime wastes and topsoil was recommended for re-vegetation in the coal overburden slopes. The lime wastes from the soda ash production might have a potential to be recycled for the reclamation of the abandoned coal mines to alleviate the environmental problems associated with coal mine waste.

• Structural Engineering and Mechanics
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• v.60 no.6
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• pp.923-937
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• 2016

The common prospect in diminishing mine-blast vibration is decreasing vibration with increasing distance. This paper indicates that, contrary to the general expectancy, vibration waves change their forms when they are travelling through the low velocity layer like coal and so-called guided waves moving the vibration waves to longer distances without decreasing their amplitudes. The reason for this unexpected vibration increase is the formation of guided waves in the coal bed which has low density and low seismic velocity with respect to the neighboring layers. The amplitudes of these guided waves, that are capable of traveling long distances depending on the seam thickness, are several times higher than that of the usual vibration waves. This phenomenon can many complaints from the residential areas very far away from the blasting sites. Thus, this unexpected behavior of the coal beds in the surface coal mines should also be considered in vibration minimization studies. This study developed a model to predict the effects of guided waves on the propagation ways of blast-induced vibrations. Therefore, vibration mitigation studies considering the nearby buildings can be focused on these target places.

• Explosives and Blasting
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• v.24 no.1
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• pp.57-62
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• 2006

The typical blasting method adopted in Pasir Coal Mine is a surface blasting technique with a single free face. It means that there is only one free face, which is usually the ground surface. This kind of blasting method is easy to use but inevitably causes enormous ground vibrations, which, in turn, can affect the stability of the slopes comprising the various boundaries of the open pit mine. In addition, the method also has the problem of lowering the blast efficiency compared to other methods such as bench blasting methods or ones with more than two free faces. In this respect, a project was launched to develop a new blasting method that is suitable for controling the ground vibration and enhancing the blast efficiency. As a part of the project, authors investigated the current blasting method as well as the overall pit developing process in the mine, and established some important guidelines that should be observed during the whole development process. This paper presents the details of the typical blasting pattern and the pit developing method in the mine, and suggests the guidelines determined from the results of the observations.

• Resources Recycling
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• v.26 no.2
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• pp.80-88
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• 2017

Globally, there has been a lot of research related to recycling coal ash from power plant stations. This research is happening because there is a considerable shortage of sites for reclamation of increased coal ash every year. In addition, a variety of environmental pollutants have appeared because of mining activity. Abandoned coal mine, pits, and mine tailing piles caused pollutants to come to the surface resulting in serious damage for humans and the environment. Therefore in this study, we investigated whether or not coal ashes have the ability to prevent several environmental problems by mining in Korea and a manageable form recycling coal ashes. In overseas countries, there is a sufficient field of applicable cases where coal ash is used for neutralizing AMD (Acid Mine Drainage), covering of the waste materials, grouting, and soil amendments. However in Korea, since the coal ash is classified as a 'waste', there is an insufficient field applicable cases so far. Therefore it is necessary to establish a specific standard and management system for the utilization of coal ash based on the relevant precedent cases applied abroad in order to prevent environmental pollution caused by mining activity in Korea.

• Journal of Korea Soil Environment Society
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• v.2 no.3
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• pp.31-38
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• 1997

Temporal and spatial comparisons of acid mine drainage contaminated waters are difficult because of the complex physico-chemical nature of the pollutant. In the present study, an acid mine drainage index has been developed and evaluated for the assessment of surface waters. AMD index is calculated using a modified arithmetic weighted index using seven parameters which are most indicative of AMD contamination, i. e. pH value, sulphate, iron, zinc, aluminum, copper and manganese. Weighting is used to express the relative indicator value of each parameter. The proposed AMD index is used to quantify contamination from acid mine drainage over ten different old mine sites and assess the degree of impact on surface on surface waters. As a result of AMD evaluation, the Sukbong Mine located near the Moonkyung province showed lowest AMD value indicating the worst acid mine drainage quality. In overall, Youngdong mine sites showed higher contaimination compared to the other mine sites including Youngsuh, Choongbu, Suhbu and Nambu area.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.10a
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• pp.59-61
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• 2005

In Korea, hundreds of abandoned and closed coal and metallic mines are present in the steep mountain valleys due to the depression of the mining industry since the late 1980s. From these mines, enormous amounts of coal waste were dumped on the slopes, which causes sedimentation and acid mine drainage (AMD) to be discharged directly into streams causing detrimental effects on soil and water environments. A limestone slurry by-product (lime cake) is produced from the Solvay process in manufacturing soda ash. It has very fine particles, low hydraulic conductivities ($10^{-8}{\sim}10^{-9}cm/sec$), high pH, high EC due to the presence of CaO, MgO and $CaCl_2$ as major components, and traces of heavy metals. Due to these properties, it has potential to be used as a neutralizer for acid-producing materials. A field plot experiment was used to test the application of lime cake for reclaiming coal wastes. Each plot was 20 x 5 m (L x W) in size on a 56% slope. Treatments included a control (waste only), calcite ($CaCO_3$), and lime cake. The lime requirement (LR) for the coal waste to pH 7.0 was determined and treatments consisted of adding 100%, 50%, and 25% of the LR. The lime cake and calcite were also applied in either a layer between the coal waste and topsoil or mixed into the topsoil and coal waste. Each plot was hydroseeded with grasses and planted with trees. In each plot, surface runoff and subsurface water were collected. The lime cake treatments increased the pH of coal waste from 3.5 to 6, and neutralized the pH of the runoff and leachate of the coal waste from 4.3 to 6.7.

• Economic and Environmental Geology
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• v.53 no.6
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• pp.793-807
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• 2020

The policy for Green New Deal will promote the shift of the application to coal as feedstock from coal as fuel. Coal can be used as fuel for production of hydrogen and as feedstock materials such as synthetic graphite or activated carbon. Hydrogen is obtained from syngas produced through Steam carbon(SC), Water-Gas Shift(WGS), and Carbonation reactions, and these processes should be used in conjunction with CO2 sequestration technology. Anthracite has a potential in terms of cost advantage as a feedstock compared to a petroleum pitch, because Synthetic graphite is prepared by heat treating an anthracite with high rank to a graphitization temperature which is in the range of 2400~2800℃, in the presence of inorganic catalyst such as silicon or iron. From several studies, it has been confirmed that coal-based activated carbon(AC) is manufactured with quality similar to the large specific surface area and much micropore volume of lignin-based AC, can be prepared. Therefore it is expected that lignin-based AC is replaced to coal-based AC.

• Geomechanics and Engineering
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• v.21 no.1
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• pp.23-33
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• 2020

An advancing cutting roof for gob-side entry retaining with no-pillar mining under specific geological conditions is more conducive to the safe and efficient production in a coalmine. This method is being promoted for use in a large number of coalmines because it has many advantages compared to the retaining method with an artificial filling wall as the gateway side filling body. In order to observe the inner structure of the gateway cutting roof and understand its stability mechanism, an equivalent material simulation experiment for a coalmine with complex geological conditions was carried out in this study. The results show that a "self-stabilization bearing structure" equilibrium model was found after the cutting roof caving when the cut line deviation angle was unequal to zero and the cut height was greater than the mining height, and the caving roof rock was hard without damage. The model showed that its stability was mainly controlled by two key blocks. Furthermore, in order to determine the optimal parameters of the cut height and the cut line deviation angle for the cutting roof of the retaining gateway, an in-depth analysis with theoretical mechanics and mine rock mechanics of the model was performed, and the relationship between the roof balance control force and the cut height and cut line deviation angle was solved. It was found that the selection of the values of the cut height and the cut line deviation angle had to conform to a certain principle that it should not only utilize the support force provided by the coal wall and the contact surface of the two key blocks but also prevent the failure of the coal wall and the contact surface.

• Explosives and Blasting
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• v.24 no.2
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• pp.51-63
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• 2006

The typical blasting method adopted in Pasir Coal Mine is a surface blasting technique with a single free face. It means that there is only one free face, which is usually the ground surface. This kind of blasting method is easy to use but inevitably causes enormous ground vibrations, which, in turn, can affect the stability of the slopes comprising the various boundaries of the open pit mine. In addition, the method also has the problem of lowering the overall blast efficiency compared to other methods such as bench blasting methods or ones with more than two free faces. In this respect, a project was launched to develop a new blasting method that is suitable for both controling the ground vibration and enhancing the blast efficiency. As a part of the project, we investigated the current blasting method of the mine, and have conducted field measurements of the ground vibrations from 12 biasts. This Paper presents the details of the typical blasting pattern and the Propagation characteristics of the ground vibration from the surface blasting in the mine. Especially, various predictive equations for peak Particle velocities that can be used to estimate the ground vibration level in the mine area were derived from the regression analyses using the measured ground vibration data.