It is thanks to a fortunate coincidence that the Mining and Gothic Museum is in possession of a cast bronze cake. This is the name for a by-product of primeval copper processing. The valuable raw material was primarily intended for further processing at the coppersmiths but was also used as payment during the Bronze Age.
In 2018 a German family salvaged this example after a mountain tour in late summer from a waterhole of the Schwarzleo stream in the vicinity of the Bronze Age mine discovered in 2004.
Mining activity during the Bronze Age took the form of an open-cast mine; this was proven by excavations by Robert Krauss and Martin Seiwald.
The family found fragments of large storage vessels made of clay mixed with slag, fine ceramics in the form of a small bowl and almost completely preserved spruce wood shingles, which probably once formed the roof of a living or workspace. Secondary minerals in the form of malachite and azurite can be found throughout the entire early mining site.
The discovery of the cast copper cake means that the smelting of ores in the mining district of Schwarzleo, while not yet proven, can now at least be assumed.
The cast copper cake, found in the summer of 2018 in the Schwarzleo stream, weighs 651 g, is oval-shaped and, with a thickness of 1 cm, relatively flat compared to other finds.
The material is solid and free of slag and charcoal. However, whether it is pure copper or copper alloy in the form of bronze will only be revealed through ongoing investigations.
Pure copper would secure Leogang as the place of origin, whereas bronze would have been delivered as for the production of mining tools.
The cast copper cake has signs that it has been at the bottom of the stream for a long time. Sanding sediments have round the edges and in some areas removed the rich green malachite patina down to the metal.
Thanks to the finders’ great understanding the cast copper cake was donated to the Mining and Gothic Museum and represents an important find for research into Leogang mining.