Abstract: This specification relates to a counter-flow sedimentation separator which is designed to separate mixed aggregate materials on either side of a preset cutoff density and to a method of separating such materials. The separator has been designed primarily to highgrade gold tailings but can be used to perform a similar function with other materials given an adequate difference in density between the materials to be separated. It employs a multi-column design which coupled with screening allows density separations to be completed throughout the usual spectrum of particle sizes found in tailings and can be modified according to the material to be processed in order to maximize efficiency.