The increasing need for robust pyrometallurgical furnace construction is driven by two trends in the copper and other base metals smelting industry: the desire for increased production within a single furnace line by greatly increasing smelting intensities, which generates high heat fluxes to the crucible walls, and the operational and economic imperatives of maintaining high percentage online times and long campaign lives between rebuilds. A key feature of furnaces capable of producing at high rates, while containing intense processes, is a strong, thermally robust wail cooling system. Equally important design aspects include the furnace steel structure, refractories, a cooling water supply and piping arrangment for safety from leaks and disruptions, and instrumentation/controls for monitoring and rapid mitigation of process excursions. Integration of the cooling elements into these furnace systems is essential for optimum performance of the cooling elements, and indeed the entire furnace. This paper discusses the development of a composite copper / refractory water-cooled design, which has been successfully implemented on several copper smelting and converting furnaces, including Kennecott's flash converting furnace, INCO's MK reactor, and Kidd Creek's converting furnace.