Dannemora mine

The Dannemora mine (Dannemora gruvor) at Dannemora in Uppsala County, Sweden was once one of the most important iron ore mines in Sweden. The mine was closed by its owners SSAB in 1992. It may have been open since the 13th century, but the first documentary reference was in 1481.

The mine has a depth of 640 metres and supplied oregrounds iron by the Walloon process (Vallonsmide) using a blast furnace and finery forge. Ironworks making sites included Österbybruk and Lövstabruk). Their products were particularly pure iron, due to the manganese content of the iron ore. This made it the best material for conversion to blister steel, the main variety of steel made in Great Britain between the 1610s and the 1850s.