Val Imperina
Access: short itinerary around the former mining center of Val Imperina
The copper valley
Val Imperina, known above all for its important mining past, is a lateral valley of torrent Cordevole, situated along the very evident structural discontinuity (Valsugana overthrust) where the very ancient rocks of the metamorphic basement (phyllites) come into contact with the stratified dolomitic rocks of Dolomia Principale (see the geological cross section). The transversal profile of the valley highlights a marked asymmetry (asymmetric valley), caused by the lithological diversity of the two slopes: the right slope, more steep (sometimes rocky) is sculpted in the compact/tough formation of Dolomia Principale, the left slope (gentler) is shaped into the soft and degradable rocks of the metamorphic basement (phyllites). However, Val Imperina is known above all for its mines that have been working, despite their ups and downs, for over five centuries (from 1400 to 1962). In the district of Val Imperina, a considerable deposit of sulfurs (above all cupriferous pyrite) was cultivated for a long time. Cupriferous pyrite (iron and copper sulfides), thanks to a complex metallurgical process (roasting, leaching, and several fusions; see notes) was used to obtain a good-quality malleable metallic copper, appreciated above all for its high resistance to alteration (for instance, it was used between the 17th and 18th century by the Serenissima Republic of Venice in cannon building, ship coating, and minting). At the end of the 19th century, after the fall of the world copper price (as a consequence of the discovery of huge deposits in Latin America), the production of Val Imperina became soon "way above market value". With the Montecatini management (1910-1962), the activity was reconverted and pyrite was used to produce sulfuric acid (used in the chemical industry for the production of fertilizers).
