• Journal of Soil and Groundwater Environment
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• v.8 no.4
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• pp.53-63
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• 2003

Objectives of this research were to fractionate heavy metals in soil samples in the upper Okdong River basin and to assess the potential pollution index of each metal fraction. Soil samples were collected from the cultivated land soils and analyzed for physical and chemical properties. pH of cultivated soils ranged from 5.2 to 7.6. Contents of total kelhaldal nitrogen and loss on ignition were in the ranges of 0.6∼2.5%, and 1.9∼12.9%, respectively. Heavy metals in the cultivated land soils were higher in the abandoned closed coal mine near field soils than those in the paddy soils. Total concentrations of metals in the cultivated land soils were in the orders of Zn > Pb > Ni > Cu > Cd, exceed the corrective action level of the Soil Environment Conservation Law and higher than the naturals were abundance levels reported from uncontaminated cultivated land soils. Mobile fractions of metals were relatively small compared to the total concentrations. Soil Pollution Assesment Index (SPAI) values of each fraction of metals were leveled from Non polluted to Moderately polluted based on total concentrations. SPAI values of mobil fractions were lower than those of immobile fractions. Results on metal fractions and SPAI values of the cultivated land soils indicate that field soils samples were contaminated with heavy metals and had potential to cause a detrimental effects on plants. A prompt countermeasure to prevent field soils in the abandoned closed coal mine near fields are urgently needed.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.5
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• pp.265-276
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• 2017

Heavy metals leaching from closed mines have been causing severe environmental problems in nearby soil ecosystems. Mine reclamation in Korea has been recently implemented based on the heavy metal immobilization (a.k.a., stabilization). Since the immobilization temporarily fixes the heavy metals to the soil matrix, the potential risk of heavy metal leaching still exists. Therefore the appropriate monitoring and the related policies are required to safeguard the soils, where all the cultivations occur. The current monitoring methods are based on either heavy metal concentration or simple toxicity test. Those methods, however, are fragmented and hence it is difficult to evaluate the site in an integrated manner. In this study, as the integrated approach, ecological functional state evaluation with a multivariate statistical tool was employed targeting physiochemical soil properties, heavy metal concentrations, microbial enzymatic activity, and arsenic respiratory reductase gene quantity. Total 60 soil samples obtained from three mines (Pungjeong, Jeomdong, Seosung) were analyzed. As a result, the stabilized layer soil and lower layer soil have shown the similar pattern in Pungjeong mine. In contrast, Jeomdong and Seosung mine have shown the similarity between the stabilized layer soil and the cover layer soil, indicating the possible contamination of the cover layer soil.

• Korean Journal of Environmental Agriculture
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• v.24 no.3
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• pp.215-221
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• 2005

Numerous abandoned or closed mines are present in the steep mountain valleys in Korea due to the depression of the mining industry since the late 1980s. From the mines, enormous amounts of wastes were dumped on the slopes causing sedimentation and acid mine drainage to be discharged directly into streams causing detrimental effects on surrounding environment. Objective of this research was to evaluate the feasibility of the lime cake by-product from the soda ash production (Solvay process) to neutralize the pyrophyllite mine wastes, which have discharged the acid drainage to soil and stream in the watershed. The pH of mine wastes was strongly acidic at pH 3.67 containing over 16% of $Al_2O_3$ and 11% of $Fe_2O_3$. Whereas the lime cake by-product was strongly basic at pH 9.97 due to high contents of CaO, MgO and $CaCl_2$ as major components. Column experiments were conducted to test the neutralizing capacity of the lime cake by-product for the acidic pyrophyllite mine wastes. The column packed with the wastes (control) was treated with the lime cake by-product, calcium carbonate, the dressing soil or combination. The distilled water was eluted statically through the column and the leachate was collected for the chemical analyses. Treatments of the mine wastes with the lime cake by-product (or calcium carbonate) as mixtures increased pH of the leachate from $3.5{\sim}4.0\;to\;7{\sim}8$. Concentrations of Fe and Al in the leachate were also decreased below 1.0 mg $L^{-1}$. A Similar result was observed at the combined treatments of the mine waste, the lime by-product (or calcium carbonate) and the dressing soil. The results indicated that the lime cake by-product could sufficiently neutralize the acid drainage from the pyrophyllite mine wastes without dressing soils.

• Economic and Environmental Geology
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• v.46 no.2
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• pp.165-178
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• 2013

This study is for the genetic differences of two closed asbestos mines from Jeongjeon and Ocheon areas in Boryoung, Chungnam. They are mined asbestos for past several decades. Host rocks are serpentinites for Jeongjeon mine and dolomites for Ocheon mine. Asbestos samples and their host rocks are collected from the field trips and examined with microscopes and FESEM, and analysed with XRD and EDX to confirm for the type and/or compositions of the minerals. The asbestos occur as layers, cracks and fractures assummed as a pathway of the hydrothermal water, but show different characteristics. The serpentinites from the Jeongjeon mine contain chrysotile, tremolite and actinolite asbestos. Non-asbestos minerals including tremolite and actinolite were also found. The chrysotiles occur as a cross fiber or slip fiber at veins and along cracks of several mm to cm thickness. Tremolite and actinolite asbestos occur along cracks and fractures of several cm to ten cm thickness. It suggests that the asbestos from Jeongjeon area were formed by the reactions between serpentinite and hydrothermal water. The dolomites of the Ocheon mine only contain tremolite and actinolite asbestos. The asbestos occur along layers, cracks and fractures, suggestive of asbestos from Ocheon area formed by the reactions between dolomite and hydrothermal waters influxed along layers, cracks and fractures. Overall results suggest that two asbestos mines showing different host rocks are located in a Boryoung area. They show a different type of asbestos minerals, reflecting variety of petrogeneses.

• Economic and Environmental Geology
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• v.31 no.2
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• pp.111-125
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• 1998

Dispersion, migration and enrichment of environmental toxic elements from the Samkwang Au-Ag mine area were investigated based upon major, minor and rare earth element geochemistry. The Samkwang mine area composed mainly of Precambrian granitic gneiss. The mine had been mined for gold and silver, but closed in 1996. According to the X-ray powder diffraction, mineral composition of stream sediments and soils were partly variable mineralogy, which are composed of quartz, orthoclase, plagioclase, amphibole, muscovite, biotite and chlorite, respectively. Major element variations of the host granitic gneiss, stream sediments and soils of mining and non-mining drainage, indicate that those compositions are decrese $Al_2O_3$, $Fe_2O_3$, MgO, $TiO_2$, $P_2O_5$ and LOI with increasing $SiO_2$ respectively. Average compositional ranges (ppm) of minor and/or environmental toxic elements within those samples are revealed as As=<2-4500, Cd=<1-24, Cu=6-117, Sb=1-29, Pb=17-1377 and Zn=32-938, which are extremely high concentrations of sediments from the mining drainage (As=2006, Cd=l1, Cu=71, Pb=587 and Zn=481 ppm, respectively) than concentrations of the other samples and host granitic gneiss. Major elements (average enrichment index=6.53) in all samples are mostly enriched, excepting $SiO_2$, $Na_2O$ and $K_2O$, normalized by composition of host granitic gneiss. Rare earth element (average enrichment index=2.34) are enriched with the sediments from the mining drainage. Minor and/or environmental toxic elements within all samples on the basis of host rock were strongly enriched of all elements (especially As, Br, Cu, Pb and Zn), excepting Ba, Cr, Rb and Sr. Average enrichment index of trace elements in all samples is 15.55 (sediments of mining drainage=37.33). Potentially toxic elements (As, Cd, Cr, Cu, Ni, Pb, and Zn) of the samples revealed that average enrichment index is 46.10 (sediments of mining drainage=80.20, sediments of nonmining drainage=5.35, sediments of confluent drainage=20.22, subsurface soils of mining drainage=7.97 and subsurface soils of non-mining drainage=4.15). Sediments and soils of highly concentrated toxic elements are contained some pyrite, arsenopyrite, sphalerite, galena and goethite.

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

• Geomechanics and Engineering
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• v.24 no.3
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• pp.227-235
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• 2021

A criterion and a method for solving a problem on the prevention of mine working fracture under the action of tectonic and gravitational forces are offered. Based on minimal criterion, theoretical analysis of the definition of the optimal shape of working in the rock mass weakened by arbitrarily located rectilinear cracks was carried out. A closed system of algebraic equations allowing to minimize the stress state and stress intensity factors depending on mechanical and geometrical characteristics of the rock, is constructed. The relation between the shape of the working and the stress intensity factors and also location and sizes of the cracks is obtained. The found optimal shape of working increases load-bearing capacity of the rock.

• Journal of Soil and Groundwater Environment
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• v.10 no.5
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• pp.25-36
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• 2005

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. Thus these disposed an enormous amount of mining wastes without a proper treatment facilities, resulting in water pollution in the downstream areas. Acid mine drainage (AMD) and waste water 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 Solids (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. Concentrations of water soluble heavy metals in the Okdong streams were in the orders of Fe>Al>Mn>Zn>Cu>Pb>Cd, indicating Fe from the AMD and waste water effluents contributed greatly to the quality of water and soil in the lower watershed of Okdong stream. Copper concentrations in the effluents from the tile drainage of mine tailings dams were highest during the raining season. Water Pollution Index (WPI) 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 tailings dams and coal mines flowed into main stream were in the WPI 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 the major source to water pollution at the Okdong stream areas.

• Economic and Environmental Geology
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• v.37 no.1
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• pp.1-19
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• 2004

Metallic deposits in Korea have a variety of genetic types such as hydrothermal veins, skarns, hydrothermal replacement and alaskite deposits and so on. Geological, mineralogical and geochemical features including host rock, wall-rock alteration, ore and gangue mineralogy, mineral texture and secondary mineralogy related to weathering process control the environmental signatures of mining areas. The environmental signatures of metallic deposits closed from early 1970s to late 1990s in Korea show complicate geochemistry and mineralogy due to step weathering of primary and secondary minerals such as oxidation-precipitation-remobilization. The potentiality of low pH and high heavy metal Concentration s from acid mine drainage is great in base-metal deposits associated with polymetallic mineralization, breccia-pipe type and Cretaceous hydrothermal Au veins with the amount of pyrite whereas skam, hydrothermal replacement, hydrothermal Cu and Au-Ag vein deposits are in low contamination possibility. The geoenvironmental models reflecting the various geologic features closely relate to disuibution of sulfides and carbonates and their ratios and finally effect on characteristics of environmental signatures such as heavy metal species and their concentrations in acid mine drainage.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.917-922
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• 2010

To assess the bioavailability of As in soils and to provide a basic information for adequate management of As contaminated fields, paddy soils and rice grains near 5 closed mines were collected and analyzed for As using sequential extraction procedure. The As contents extracted with 1M HCl against total As content in soils were ranged from 5.4 to 41.9% ($r=0.90^{**}$). However, these two contents of As in soils were not positively correlated with As concentration in rice grains. Major As fractionation of paddy soils was residual form ranging 38.1 to 84.1% except NS mine. Also, specially adsorbed fraction and fraction associated with amorphous Fe and Al oxyhydroxides, which are partially bioavailable As fractionation to the rice plant, were positively correlated with As in rice grains while fraction associated with crystalline Fe and Al oxyhydroxides and residual form were not correlated.