Comprehensive Assessment on Utilization of Iron Ore Tailing as Backfill Material in Mechanically Stabilized Earth Wall

Abstract

World is bestowed with self-sufficient magnetite and hematite iron ores. Huge volume of mining waste, namely iron ore tailings (IOT), is generated during processing of iron ore, leading to environmental concerns. At the same time, due to excessive usage and environmental regulations, there is scarcity of naturally available granular material. This paper presents the detailed laboratory study carried out to ascertain the feasibility of adopting iron ore tailings as an alternate granular backfill material in mechanically stabilized earth wall. A comprehensive study on mineralogical, physiochemical, and geotechnical characteristics was carried out on IOT procured from Lakhya dam, Chikkamagaluru district, Karnataka, India. X-ray fluorescence study indicates the presence of silica as major mineral along with hematite as major iron-bearing mineral. IOT is classified as a poorly graded sand with high friction angle value varying between 44° and 50° under loose and dense states and negligible particle breakage under compaction. The environmental risk connected with IOT was assessed through leaching studies and it was characterized as low contamination low ecological risk material. Design of mechanically stabilized earth (MSE) wall with IOT and granular soil as backfill using tie-back wedge method revealed that identical number of reinforcement layers are required when iron ore tailing or granular soil is used as backfill. Further, finite element modeling of MSE wall with IOT and river sand as backfill was carried out to compare the deformation behavior. MSE wall with IOT as backfill showed 70% reduction in horizontal facing displacement in comparison with sand backfill. © The Author(s), under exclusive licence to Indian Geotechnical Society 2024.