강원도 도계 폐탄광에 형성되는 산성광산 배수와 황갈색 철수산화물에 대한 지구화학 특성

Abstract

This study was to investigate the geochemistry and the indigenous acidophilic bacteria in the acid mine drainage from the abandoned Dogye coal mine, Gangwon-do. The pH values were measured range from 3.02 to 3.57 in the mine drainage, and the content of Fe ions detected range from 1.91 to 295.9 mg/l. The size of the rod-shaped bacteria observed in the acid mine drainage ranged from 0.3×1.3 ㎛ to 0.4×3.4 ㎛, and sheathed-filament bacteria were observed in the yellow-colored iron hydroxide. These rod-shaped indigenous bacteria were grown in a growth-medium containing elemental sulfur and Fe2+ ion. As the rod-shaped bacteria were growing, the pH value was decreased from 3.72 to 2.08, whereas the Eh values were increased in the growth-medium. In decreasing the pH value and increasing the Eh value in the growth-medium and the subculture, it was identied that the rod-shaped indigenous bacteria were utilized the Fe2+ and elemental sulfur. The yellow-colored iron hydroxides mainly consisted of Fe2O3, SiO2, Al2O3 and S, and these contained As(maxi. 37 mg/kg), Cr(maxi. 74 mg/kg), Cu(maxi. 29 mg/kg) and Zn(maxi. 161 mg/kg). In the XRD analysis, the amorphous iron hydroxide, goethite, gypsum and quartz were identified in the yellow-colored iron hydroxide. The zero point of charge of the yellow-colored iron hydroxide were determined to range from 4.1 to 7.1 using zeta potential. The heavy metal contents were measured at a maximum in the alkali-supply pond, the oxidation pond, and the wetting pond.