Sphalerite weathering and controls on Zn and Cd migration in mine waste rock: An integrated study from the molecular scale to the field scale

•Cross-scale analytical techniques are utilized to delineate mechanisms of sphalerite weathering in a mine waste-rock pile.•Oxidation causes congruent dissolution of sphalerite.•Secondary sequestration of Cu occurs locally on the surfaces of sphalerite.•Zinc and Cd migration is controlled by pH-dependent reactions on the surfaces of Fe-oxhydroxides.•Continuous release of Zn and Cd is expected in the seepage in absence of remedial efforts.