Recent develognents in zinc flotation at the North Broken Hill Limited concentrator are discussed. An outline of the history of zinc flotation and a description of current practice is presented. Installation of on-stream X-ray analysis probes has resulted in inproved metallurgical performance and focussed attention on automatic control._x000D_
Results are presented of investigations made over the past six years which have led to the formulation of experimental schemes for the automatic control of zinc flotation.