All in all there are ten known copper mines and two iron mines on the Ølve peninsula. Geologically, the nine mines on Varaldsøy Island also should be figured in. The industry began at Lilledal in 1642 wth the mining of iron ore. From Jernsmauget by Dyråsen, the iron ore was sent to the iron works in eastern Norway.
Large quantities of nickel ore have been mined from Litlandsvatnet, between Lonevågen and Hosanger. The discovery was made in 1875. During the period of operation from 1882 to 1945, 4170 tonnes of pure nickel were extracted from 462 000 tonnes of ore, a large production by Norwegian standards.
During the summer of 1979 a rock was found at Lykling in Bømlo that contained 450 grams of gold, and at the end of the 1980s a great many gold samples were laid out for sale. In the old mining area there are still gold miners hunting for the precious metal. But, the big adventure stories are a thing of the past.
Siggjo is a cone-shaped, volcano-like mountaintop in the part of Hordaland where one finds the best preserved volcanic rocks. The rock types originate from one or several volcanoes that spewed out glowing lava and ash. But, the shape of the mountain, as it appears today, formed later and by completely different forces.