Geochemistry of ochreous precipitates from coal mine drainage in India

• Published in: Environmental earth sciences 2010-08, Vol.61 (4), p.723-731
• Main Authors: Equeenuddin, Sk. Md, Tripathy, S., Sahoo, P. K., Panigrahi, M. K.
• Format: Article
• Language: English
• Subjects: Acid mine drainage; Ammonium; Biogeosciences; Coal mines; Coal mining; Drainage; Earth and Environmental Science; Earth Sciences; Earth, ocean, space; Electron microscopy; Engineering and environment geology. Geothermics; Environmental Science and Engineering; Exact sciences and technology; Geochemistry; Geology; Hydrology/Water Resources; Infrared spectroscopy; Metals; Mineralogy; Organic carbon; Original Article; Pollution, environment geology; Sedimentation & deposition; Silicates; Terrestrial Pollution; Water geochemistry
• ISSN: 1866-6280; 1866-6299
• DOI: 10.1007/s12665-009-0386-9

The deposition of ochreous is common by a consequence of acid mine drainage (AMD). The ochreous precipitated from the AMD sites around Tertiary coalfield of Assam, India were collected and characterized by X-ray diffractometry (XRD), Fe to S molar ratio, ammonium oxalate acid (pH 3.0) extraction, fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The ochreous mainly consists of goethite, schwertmannite, ferrihydrite and jarosite. Mineralogy of ochreous was controlled by the pH whereas formation of ferrihydrite was favored at high organic carbon content. Role of bacteria for the formation of secondary minerals was observed. Mobility of metals was controlled by the ochreous, and they were also retained during the process of phase transformation of poorly ordered iron-oxyhydroxysulfates into the stable forms.