Numerical analysis of the stability and minimum required strength of sill mats considering creep behavior of rock mass

• Rock creep significantly increases the minimum required cohesion (cmin) of sill mats, especially at large mine depths. • Neglecting rock creep can lead to unsafe underestimation of cmin, risking sill mat failure. • For deep mines with severe rock creep, ductile cemented backfill (low stiffness, adequate strength) is recommended to reduce binder use and prevent crushing. • Prompt filling of the stope below the sill mat improves stability and reduces cmin.