화순 폐탄광지역 광산배수와 침전 및 증발잔류광물에 대한 지구화학적 및 광물학적 연구

This study investigated the geochemical characteristics of mine drainage discharged from an abandoned coal mine in the Hwasoon area. Surface water samples were collected from 23 locations along the Hancheon creek. The concentration of Zn and Cu in stream waters was highest at low pH(3.53), whereas the content of TDS and TDI was highest at high pH (7.78) due to the concentration of Ca, HCO₃and SO₄. At the upstream site, the Ba, Fe, Mn, zn, and SO₄contents were relatively high but decreased significantly with the distance from the coal mine. On the contraty, the Na and NO₃contents were low at the upstream site but increased downstream. Yellow precipitate material collected in the Hancheon consisted mainly of iron and LOI. This yellow precipitate was heated from 100 to 990℃ for 1 hour. With increasing temperature, the intensity of hematite peaks were sharply produced in X0ray pattern and the absorption band Fe-O of hematite increased in IR due to dehydration and melting. The yellow to brown precipitate and evaporite materials were collected by a air-dry from the acid mine water at the laboratory. After drying, the concentration of ions in the acid water samples increased progressively in oversturation with respect to either gypsum, ferro-hexahydrite or quenstedetite. The X-ray powder diffraction studies identified that the precipitated and evaporated materials after drying were well crystallized gypsum, ferrohexahydrite and quenstedetite. Diagnostic peaks used for identification of gypsum were the 7.65, 4.28, 3.03, 2.87 and 2.48Å peaks and those for ferr-hexahydrite were the 5.16, 5.12, 4.89, 4.44, 4.05, 3.62, 3.62, 3.46, 3.40, 3.20, 3.03, 2.94, 2.53, 2.28, 2.07, 1.88 and 1.86Å peaks. The IR spectra with OH-stretching, deformation of H₂O and SO₄2-stretching vibration include the existence of gypsum, ferrohexahydrite and quenstedetite in the precipitated and evaporite materials. In the SEM and EDS analysis for the evaporite material, gypsum with well-crystallized, acicular, and columnar from was distinetly observed.