Smelting of gold and silver ores in Renaissance Austria

The gold and silver smelting area of the Angertal valley is located in the Gastein region, in the south west of Austria, and is linked to the Bockhart mining area, where there is evidence for mining of gold and silver ores. The principal minerals containing the noble metals are galena and pyrite, with variable amounts of sphalerite, chalcopyrite and arsenopyrite. Extensive mining of the Bockhart goldand silver-bearing veins started during the fourteenth century and ended at the end of the nineteenth century, with a peak of activity, according to written sources, in the second half of the sixteenth century. Excavation of one site in the Angertal valley revealed several well-preserved furnaces, used for smelting ores, and a vast amount of smelting slag, pieces of ore, furnace wall fragments, and charcoal. Their nature, quantity and degree of preservation made this site ideal to investigate the large-scale smelting technology of noble metal ores during the Renaissance, as a contribution to a larger project reconstructing the socio-economic dimensions of the metallurgical activity in this region. This paper presents the first results of the ongoing analytical study by optical microscopy, SEM-EDS and ED-XRF of ore, matte and slag. The slag is mostly fayalitic, and the presence of matte links the smelting process to the sulphidic ores from the region. A preliminary reconstruction is presented of the high-temperature processes performed to extract the noble metals from their ores.