A Combination of Acid B Extra ™ and Biochar to Reduce Metal Concentrations in Acid Mine Drainage

Abstract

The Bureau of Land Management (BLM) Abandoned Mined Land Program has built and is operating the Eveline Mine Drainage Treatment Vault near Silverton, CO to investigate innovative passive treatment technologies for acid mine drainage (AMD) in high alpine environments. Column tests of several materials were conducted to determine treatment media to use in the vault. This case study examines the potential of combining Bauxsol Acid B Extra (an alumin are fining by-product) with biochar, pea-gravel, and porous concrete to reduce AMD metal concentrations. The objective of the trial was to create a passive treatment system that (1) reduces metal concentrations in effluent waters, (2) reduces operational costs, (3) utilizes waste streams from industry, and (4) operates in cold weather climates with limited space for infrastructure. Results suggest that the combination of Acid B Extra and biochar achieved optimal near term results with >95% removal of Cd, Cu, Fe, Mn, and Zn, and >60% removal of Al, while not clogging the pilot test columns.