The principal method for extracting copper was heating the rock via large fires, known as fire-setting. When the rock cooled down, it would become brittle and crack, allowing manual tools such as wedges and sledge hammers to be brought to bear. After the ore had been transported out of the mine it was roasted to reduce sulfur content in open hearths. The thick, poisonous smoke produced would be a distinguishing feature of the Falun area for centuries. After the roasting, the ore was smelted; the output of which was a copper rich material. The cycle of roasting and smelting was repeated several times until crude copper was produced. This was the final output from the mine; further refinement took place at copper refineries elsewhere. This process was used without any major change for seven centuries, until the end of the 19th century.Rydberg, p. 14 It is likely that the methods and technology for fire-setting and drainage were imported from German mines, such as in the Harz Mountains.ICOMOS, p. 1
