THE recent announcement that the Zinc Corporation Ltd., as the result of the work done in their initial plant unit at Broken Hill, has definitely adopted the "Horwood" process for separating the lead and zinc constituents of their slime concentrates, has removed any doubts that may have been entertained as to the practicability of this process. The class of material being treated is too fine to be capable of separation on concentrating tables, and formerly' was sold to European works as a low-grade zinc concentrate at a, comparatively speaking, nominal price. The buyers of this material are unable to make adequate payment for the lead and silver contents, largely owing to the fact that in the roasting operation preceding the distillation of the zinc, and in the distillation process itself, material losses of these metals necessarily occur. As these slime concentrates are invariably rich in silver and lead, the importance of recovering as much as possible of these metals as a combined product will readily be understood in view of the advantages accruing from its disposal to the lead smelting works, where high recoveries of these metals can be achieved, and from whom much higher returns can consequently be obtained than when the material is sold as a mixed zinc-lead concentrate to the zinc distiller.