Telemark has a very old tradition of industry, mining and quarrying. At Eidsborg in Tokke, a 100 km from the coast, the quarrying of whetstones started more than a millennia ago. The stones were transported to Skien, across lakes, waterfalls, and rapids, and exported all over Scandinavia.
Norway's first mine was started around 1500 in the area of the municipalities of Fyresdal and Seljord. Fossum Iron Works near Skien is the oldest iron work in Norway. It was in operation from 1539 to 1869. Åmdals Verk in Tokke is a copper mine founded in 1540.
The most important resources mined in Telemark are niobium, molybdenum, nickel, quartz, copper and iron. Limestone is still mined for a cement factory at Brevik.