High grade iron ore deposits in tropical areas are capped by a hard, erosion-resistant iron duricrust that protects the friable ore below [1]. Geochemical evidence suggests that biogeochemical cycling of iron has played a critical role in formation and ongoing evolution of these duricrusts even until the present day [2]. Hotspots for microbial activity in pools perched on iron duricrusts in Brazil indicates that extensive microbial iron cycling is occurring, with 5-25 ppm soluble iron typically measured, and up to 1000 ppm soluble iron detected in one instance. Novel iron reducing enrichment cultures have been obtained from microbial hotspots in the iron duricrust ecosystem and they are effective at goethite dissolution (up to 20% goethite reduction). One of these novel iron reducing microbial consortia was central in driving iron cycling and promoting iron duricrust re-formation from iron mine waste material in a 15-month pilot-scale experiment in Brazil. Effective microbial iron reduction was observed in all treatments during the pilot scale experiment. At end-harvest, the strongest aggregation of the iron duricrust fragments was observed in treatments that involved in situ microbial iron reduction (compared to ex situ). This technology holds promise for re-formation of iron duricrusts and accelerated remediation of iron ore deposits post-mining.