A study of iron smelting at Lopanzo, Equateur Province, Zaire

The equatorial rain forests of Zaire, central Africa, were once home to an apparently unique variant of the bloomery iron smelting furnace-the slag tapping bowl furnace. The few recorded examples of this type are 50-100 cm in diameter, and have a single tuyere blown by two or more sets of valveless drum bellows. A second pit is dug alongside to receive the slag, which is tapped through a slit or tunnel linking the bowl furnace and slag pit. All three recorded examples of this technology are instances of 'salvage ethnography'-reconstructions of extinct processes by former practitioners-and are certainly less productive than they once were. We report here the results of petrographic and metallographic examination of specimens of ore, slag and bloom from reconstructions undertaken in 1973 and 1989 in the village of Lopanzo.