• 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.

• Economic and Environmental Geology
• /
• v.35 no.1
• /
• pp.55-66
• /
• 2002

There are several abandoned coal mines around Donghae mine area in the Taebaek coal field. Two major creeks, Soro and Sanae, are contaminated with the colored precipitates formed from the coal mine drainages. Bed rocks of the study area consist of limestone, shale, and sandstone. Limestone consisted mainly of calcite and dolomite, and shale of quartz, pyropyllite and chlorite, and sandstone of quatz and illite. Coal coal spoil dumps composed mainly of pyrite and chlorite. The oxidative dissolution of sulfide minerals leads to acid mine drainage and adds the metal ions in the stream water. The ion concentrations of Fe, Ca, Mg, Al, Si, SO$_{4}$in the stream polluted by AMD are generally higher than those in the unpolluted stream water. High concentrations of Ca and Mg, Al and Si can be resulted from dissolution of carbonate minerals such as calcite, dolomite and aluminosilicates such as chlorite, pyrophyllite. Although the Fe, Al, Si, SO$_{4}$ contents are considerbly high in the acid water released from the mine adits, they become decreased downstream due to dilution of unpolluted water and precipitation of oxide/hydroxide and sulfate minerals on the bottom of stream.

• Journal of the Korean Society of Groundwater Environment
• /
• v.5 no.1
• /
• pp.44-55
• /
• 1998

Imgok creek is the most severly polluted one out of the streams which have been being polluted by acid drainages from the abandoned coal mines in the Gangdong-Myeon area, the central part of the so called Gangreung coal field. Imgok creek is being mainly polluted by the drainage from Youngdong coal mine, which supplies such pollutants as Mg, Fe, Al, Si, Ca, Mn, and SO$_4$as major dissolved components and Cr, Co, Ni, Cu, Zn, Rb, Sr, Cd, Pb, and U as minor dissolved components. After the influx, the pollutants migrate mainly as dissolved solid, rather than as suspended solids along Imgok creek. The suspended solids in Imgok creek are very rich in Fe and Al, indicating that they mainly consist of the precipitates of present and past from the polluted water. Most of the dissolved components in the stream waters of Imgok creek removed from the aqueous phase by precipitation and dilution before reaching the East Sea, so that water quality of the downstreams of Imgok creek is very similar to that of unpolluted tributaries. It suggests that Imgok creek itself is now being severly polluted by the acid drainages from the abandoned coal mines, but the East Sea is relatively safe from the same pollution. The estuary and sea waters around the Goonseon estuary, which accepts Imgok creek water, certainly show no significant difference in chemical compositions from the mean oceanic water. The bottom sediments at the sampling sites of the sea waters also show no significant trend of their component variation, especially the variations of Fe, SO$_4$ and Al concentrations. These facts again supper that the acid mine drainage is not considerablly polluting the East Sea. However, the tributaries supplying the fresh water to the Imgok creek will be certainly polluted by the acid mine drainage as time passes and pollutants will have more chance to migrate in significant amount to the downstream area, which all can be a real threats to the East Sea on the pollution possibility. Therefore, it is suggested that urgently required are not only water quality and environmental improvement of the severely polluted Imgok creek but also preparation of the measures on the possible future pollution of the East Sea by the acid drainage from the abandoned coal mines in the area, while the East Sea is still not much affected by the pollution of the same kind.

• Journal of the Korean GEO-environmental Society
• /
• v.12 no.2
• /
• pp.15-22
• /
• 2011

In this study, the effect of surface coating on iron-sulfide mineral for preventing the product acid mine drainage(AMD) was progressed by oxidation process of sulfide minerals abandoned mine Area. Three abandoned mines, Yongdong coal mine, Sil Lim mine, and Il Koang mine were selected as a sulfide mineral resource due to higher contamination rate. Six coating agents, apatite, limestone, mangnite, dolomite, bentonite, and cement were used for preventing the AMD with $H_2O_2$ and NaClO as a oxidizing agent helping for oxidizing process on sulfide minerals. Experimental results showed that sulfide mineral surface was coated effectively. Cement has a higher ability of preventing AMD when the ratio of cement to mineralis 1:1 and experimental condition is maintaining 4Days.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2004.04a
• /
• pp.167-174
• /
• 2004

Several metalliferous and coal mines, including Myungjin, Seojin and Okdong located at the upper watershed of Okdong stream, were abandoned or closed since 1988 due to the mining industry promotion policy and thus disposed an enormous amount of mining wastes without a proper treatment facilities, resulting in water pollution in the downstream areas. AMD and waste effluents from the closed coal mines were very strongly acidic showing pH ranges of 2.7 to 4.5 and had a high level of total dissolved solid (TDS) showing the ranges of 1,030 to 1,947 mg/L. Also heavy metal concentrations in these samples such as Fe, Cu, Cd and anion such as sulfate were very high. These parameters of AMD and effluents were considered to be highly polluted as compared to those in the main stream area of the Okdong river and be major pollutants for water and soil in tile downstream area. Pollution indices of the surface water at the upper stream of Okdong river where AMD of the abandoned coal mines was flowed into main stream were in the ranges of 16.3 to 47.1. On the other hand, those at the mid stream where effluents from tailing dams and coal mines flowed into main stream were in tile ranges of 10.6 to 19.5. However, those at the lower stream were ranged from 10.6 to 14.9 These results indicated that mining wastes such as AMD and effluents from the closed mines were tile major source to water pollution at the Okdong stream areas.

• Korean Journal of Ecology and Environment
• /
• v.45 no.1
• /
• pp.72-81
• /
• 2012

We investigated the effects of acid mine drainage (AMD) from abandoned coal mines on benthic macroinvertebrate communities in the upper reaches of the Nakdong River from May to October in 2009. Qualitative and quantitative sampling (Surber sampler: $50{\times}50$ cm; mesh size, 0.2 mm) was conducted at 7 study sites and 3 control sites in the study area. We thus sampled 117 species belonging to 53 families, 15 orders, 6 classes, and 5 phyla; the Ephemeroptera, Plecoptera, and Trichoptera group (EPT-group) represented the majority of the benthic macroinvertebrate community (71 species; 64.5%). In the quantitative sampling, a total of 11,575 individuals belonging to 58 species of benthic maroinvertebrates were sampled from the study sites (Sites 1-7), whereas 2,844 individuals belonging to 79 species were sampled from the control sites (Sites A-C). Tolerant species such as oligochaetes, $Epeorus$ $pellucidus$, $Baetis$ $fuscatus$, Hydropsychidae species, and Chironomidae species were predominant in the study sites. The community indices for the study sites, such as MacNaughton's dominance index (DI) (mean${\pm}$SD, $0.52{\pm}0.21$; range, 0.33-0.85) and the Shannon diversity index ($H^{\prime}$) ($2.06{\pm}0.60$; 1.06-2.57), were different from those for the control sites (DI: $0.29{\pm}0.07$, 0.22-0.35; $H^{\prime}$: $3.13{\pm}0.14$; 3.03-3.30). In the study sites, shredders and scrapers were scarce, whereas gathering-collectors (mainly Chironomidae species) were relatively abundant, as were clingers and burrowers. The detrended correspondence analysis (DCA) and similarity analyses showed that benthic macroinvertebrate communities in the study sites were clearly separated from those of the control sites, with the greatest dissimilarity being noted at the uppermost study site (Site 1), which is located close to an abandoned coal mine. The Korean saprobic index (KSI) and the ecological score using benthic macroinvertebrates (ESB) showed that the uppermost study site (Site 1) was ${\alpha}$-mesosaprobic or heavily polluted, whereas other study sites were in a fair or relatively good condition.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.26 no.5
• /
• pp.33-46
• /
• 2023

In this study, carbon storage in the aboveground biomass, litter layer, and soil layer was calculated for abandoned mining restoration areas to determine the level of carbon storage after the restoration project through comparison with the ecological reference. Five survey sites were selected for each abandoned mining restoration area in Boryeong-si, Chungcheongnam-do, and the ecological reference that can be a goal and model for the restoration project. The carbon storage in the restoration area was 0~21.3Mg C ha^-1, the deciduous layer 3.3~6.0Mg C ha^-1, and the soil layer(0-30cm) 8.3~35.1Mg C ha^-1, showing a significant difference in carbon storage by target site. The total carbon storage was between 6.1 and 35.3% of the ecological reference, with restoration area ranging from 14.0 to 62.4 Mg C ha^-1. The total carbon storage in the restoration area and the ecological reference differed the most in the aboveground biomass and was less than 12%. Based on these results, forest restoration area need to improve the carbon storage of forests through continuous management and monitoring so trees can grow and restore productivity in the early stages of the restoration project. The results of this study can be used as primary data for preparing future forest restoration indicators by identifying the storage of abandoned mining restoration areas.

• Economic and Environmental Geology
• /
• v.35 no.3
• /
• pp.241-255
• /
• 2002

The purpose of this study is to investigate environmental geochemical characteristics for the acid mine drainage and stream sediments in the abandoned Honam coal mine area. For the chemical analysis, stream winter samples were collected at 54 sites and for the mineralogical and chemical analysis, stream sediments samples were collected at 34 sites. Physical and chemical characteristics of stream water were measured at the site and chemical compositions were analyzed by ICP-AES, ICP-MS and IC. Mineralogical characteristics of stream sediments samples were determined using XRD, SEM and EDS. In physical and chemical properties, stream water shows thats pH 2.85~8.12, Eh -62~215 mV, EC 0.205~146 ms/m, ER 0.234~255 {$\Omega}{\cdot}$m, DO 0.03~1068 mg/L and TDS 10.96~1420mg/L. In chemical compositions, we obtain that K 0.118~3.184 mg/L, Mg 2.1~114.48 mg/L, Ca 2.59~l25.02 mg/L, Al 0.01~44.72 mg/L, Fe 0.108~89.49 mg/L and Na 5.45~125.41 mg/L. Stream sediments are commonly composed of quartz, illite and goethite in the result of x-ray diffraction. After heat treatment at 98$0^{\circ}C$, the hematite peaks are distinctly shown. In consideration of heavy metals (include Fe) for steam sediments, Fe ranges 22575~34713 ppm, Zn 41.66~970.3 ppm, Cd 0.52~52.07 ppm, Cu 1.25~198.5 ppm and Pb 0.43~77.35 ppm.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2000.03b
• /
• pp.117-124
• /
• 2000

This paper presents the construction planning and the detail design of a 16.2 km long railroad tunnel in a mountainous area. Major design conditions for railroad are the single track, loop-typed alinement, and a maximum grade of 24.5$\textperthousand$. A underground station(double track) with a length of 1.1km is located in the middle of the line for train cross-passing. Tunnel is excavated in highly complex geological conditions including faulted areas, abandoned mine works areas, and various rock types such as sandstone, shale, limestone, and coal seam partly. Drilling and blasting method was adopted because it is more flexible than TBM(Tunnel Boring Machine) as a result of risk assessment for geological conditions in this area. Two working adits were planned to adjust the construction schedule and can be used for ventilation and maintenance in operation phase. New material and concept were introduced to the tunnel drain design. They are expected to improve tunnel drain condition and capability. Rational tunnel support design was tried to consider the various tunnel size and purpose and to use the geological investigation results.

• Economic and Environmental Geology
• /
• v.36 no.2
• /
• pp.111-121
• /
• 2003

The objective of this study is to investigate the physical and chemical properties for environmental assessment of water system affected by acid mine drainage (AMD) from coal mining activities in the Youngwol, Jungseon and Pyungchang areas in Korea. During November 2000 to July 2002, 6 times of water samples were collected season-ally from acid mine drainage and nearby streams at 13 coal mines in the study area. The physical and chemical properties including pH, Eh, TDS, salinity, bicarbonates and DO were measured in the field. Eighteen cations includ-ing Al, Ca, Fe, Mg, Mn and Zn, and 6 anions including nitrates and sulfates were also analyzed by ICP-AES and If, respectively. Acid water from the Jungam coal mine has typical characteristics of AMD with very low pH(3∼4) and high TDS(1,000∼5,000 mg/1). Relatively high concentrations(mg/kg) of heavy meals, especially for Al(380), Fe(80), Mn(44) and Zn(8), were found in water samples from the Jungam coal mine area. Water samples from the Seojin, Sebang and Sungjin coal mines also contained over 50 mg/l of Al, >100 mg/1 of Fe and )10 mg/1 of Mn. In addition to anioins, over 1,000 mg/l of sulfate was found in several water samples. Seasonally, the concentrations of metals and sulfates varied; wet season samples were relatively higher in metals and sulfates than dry season samples. It is needed to establish the proper remediation and environmental monitoring of the AMD continuously.