The Otro Mines
There are manganese mines along the path leading to Otro. The Otro Valley contains manganese deposits in calcsist and quartzite, which are considered to be of excellent quality as they are free from traces of nickel and iron.
Here, the ore was extracted using explosives, collected and transported down to the valley by cableway. The deposit, which extends as far as the Belvedere area near Otro where it outcrops, was granted on 28 November 1938 to Ferriere Piemontesi, which was later acquired by the FIAT group, and was mined until 1949, primarily to supply the war industry. Manganese is, in fact, an essential mineral for the production of stainless steel and aluminium alloys.