Mine tailings from an open‐pit molybdenum mine were discharged at 50 m depth to Alice Arm, B.C., Canada, during 1981–1982 We report here the results of a sediment‐trap survey to determine the scale of transport of suspended tailings within the fiord. Tailings clearly affect the particle fluxes in the deeper water of Alice Arm out to a distance of about 12–14 km, as demonstrated by increased particle fluxes and enrichment of these particles in heavy metals (Cd, Zn, Pb). However, the disposal strategy appears to have been effective in trapping suspended tailings within Alice Arm; there was no evidence of tailings entering surface water or escaping the inlet Three months after the mine closed, particle fluxes in Alice Arm dropped to natural or near‐natural levels. Natural inorganic particle delivery is abo recorded in the traps as seasonal pulses from rivers draining into the head and sides of the arm.