Investigation of the Oxidation Rate of Sediments from AMD Using Humidity Cell Test

Abstract

Abstract-In this study the humidity cell test was carried out on two sediment samples from the basin of acid mine drainage around coal mine area. The samples were characterized using XRD and XRF for their mineralogical and elemental compositions respectively. The acid generation potential of the sediments was determined using the acid base accounting, through the balance between the acidity potential and neutralization potential. The release of other pollutants such as sulfate and metals was monitored through weekly analysis using Multiparameter Bench photometer and inductively coupled plasma optical emission spectrometer. The results show acidity formation from the early weeks and consistency throughout the test; the same trend was observed with the generation of pollutants such as SO4, Fe, Ni and U; the maximum release rate from samples UDB and IAD2 was SO4 2-: 9707; Fe: 839.1; Ni: 9.5; U: 0.127 mg/kg/week and SO4 2-: 1473; Fe: 215; Ni: 6.78; U: 0.041 mg/kg/week respectively. The acidity potential was found to exceed the neutralization potential of sediments, implying high risk of acid generation overtime.The findings in study inform about the consistent risk of the pollution of surface water around the coal mine area.