Numerical modeling of adaptive minefill operation: Leverage of multiphysics interactions

Mining activities are advancing into deep formations and frigid regions as mineral resources deplete, posing unprecedented challenges for contemporary underground tailings disposal. A critical concern pertinent to the emerging geographical transition is thus how the broadening spectrum of temperature configuration would influence the cost-efficiency of mine backfilling operations. To address the knowledge gap, multiphysics simulation is thus carried out in this study to replicate the perplexing backfill behavior in the exceedingly harsh thermal environment by establishing an evolutive thermo-poroelasticity framework. Our computation suggests that while catalyzing substantial non-monotonicity in the backfill response, the intricate THMC interactions could still enable unique pathways for innovating adaptive operation solutions. We have hence explored the optimal backfilling practice by leveraging judiciously the cross multiphysics couplings for practical temperature settings. Our investigation indicates that because of the prevailing effect of thermal water contraction, prioritizing filling of shallow or cold cavities could typically deliver superior stability in the long term regardless of placement temperature. Moreover, we have also demonstrated that given the suppressed thermal pressurization, enhanced fluid transmissivity and accelerated strength gain associated with higher temperature, maximizing backfilling capacity in hot season might also represent an ideal scheme for most underground mines of practical geothermal conditions.