Evaluation of tailings migration and hydrogeological behaviour in co-disposal backfilling of the Canadian Malartic mine pit

Co-disposal of waste rock and tailings (WR&T) represents a promising alternative to conventional mine waste management, by depositing both materials in a single storage facility.This alternative reduces the required storage space and improves the properties of the waste materials, leading to safer and less environmentally hazardous facilities.The interaction between WR&T is crucial for efficient construction and operation, including the potential migration of tailings into the pores of waste rock.Since most past studies have focused on mixtures, co-disposal interactions between WR&T are seldom studied.This study presents a laboratory investigation of the migration of tailings into dry waste rock, once both materials are in direct contact.Multiple simple migration column tests were performed, varying the particle size distributions of the waste rock and the solids content of the slurry tailings.The adopted methodology was elaborated through consideration of existing empirical filter criteria.The results show that the grading of waste rock and the tailings' water content significantly influence tailings migration.The results will contribute to establishing criteria for evaluating the mixing of both types of mine waste in co-disposal facilities.