2003 Seattle Annual Meeting (November 2–5, 2003)

Paper No. 15
Presentation Time: 1:30 PM-5:30 PM

PERFORMANCE EVALUATION OF A PASSIVE TREATMENT SYSTEM TREATING MINE DRAINAGE IN THE ABANDONED DONGHAE COAL MINE, KOREA


YIM, Gil Jae1, CHEONG, Young Wook1 and JO, Young Do2, (1)Geological and Environmental Hazards Division, Korea Institute of Geoscience and Mineral Rscs, 30, Gajeong-dong, Yuseong-gu, Daejeon, 305-350, South Korea, (2)Geotechnical Engineering Division, Korea Institute of Geoscience and Mineral Rscs, 30, Gajeong-dong, Yuseong-gu, Daejeon, 305-350, South Korea, gjyim@kigam.re.kr

As of 2003, over 30 passive treatment systems have been built to treat mine drainage from closed coal mines in Korea. However, maintenance costs for the passive treatment systems currently installed at the abandoned mines are increasing due to some problems such as low metal removal efficiencies, overflows and accumulation of sludge. Moreover, passive treatment systems will be constructed at many closed mines, and similar problems be likely to be encountered in near future. So, measures to improve performance of the treatment system are required. An experimental study was undertaken to evaluate the performance of the passive treatment system. A passive treatment system in the Donghae coal mine, which consists of successive alkalinity producing systems (SAPS1 and 2), oxidation pond and oxic wetland with cattail, was selected for this study. The area of the whole treatment system is 4,724 m2, and the flow rate of influent is 269 ton/day. Hydraulic loading rate (HLR) in SAPS1, SAPS2, oxidation pond and oxic wetland were 0.11m/d, 0.20m/d, 0.55m/d, and 0.32m/d, respectively. Total loading rate of the metallic constituents of Fe, Al and Mn, was about 50.160 g/day. Chemical analysis showed that 100% of Fe and Al was removed by the treatment system. The removal rates for the Fe constituent were found as 13.6g/m2/d by SAPS1, 5.1g/m2/d by SAPS 2, 4.6g/m2/d by the oxidation pond, and 0.1g/m2/d by the oxic wetland. The pH of the influent and outflow was 3.81 and 6.36, respectively. SAPS play the important role in which the vertical flow through mushroom compost and limestone layers introduced alkalinity to minewater. It was observed that lots of brownish sludge resulted from oxidation in standing water heavily accumulated on the top of SAPS1 and SAPS2. This indicated that the sludge reduced the permeability of substrates of SAPS and impeded down flow in SAPS. Finally, remaining mine drainage not passed through substrates would discharge without any purification. It is considered that performance of SAPS depends on blockage of pores in substrates due to sludges.