La ricchezza geologica dell’Altipiano del Calisio è conosciuta fin dall’antichità dai suoi abitanti e dai signori della vicina Trento. Alcune risorse del sottosuolo hanno avuto un ruolo molto importante nello sviluppo di questo territorio.
Il nome stesso deriva dai giacimenti d’argento coltivati nel Medioevo da minatori di origine germanica, i canòpi, che estraevano il prezioso metallo per conto del Principe Vescovo: con l’argento del Calisio si coniava allora la moneta di Trento. Al loro lavoro dobbiamo il paesaggio lunare che caratterizza l’area centrale dell’Ecomuseo, crivellato da migliaia di pozzi e chilometri di stretti cunicoli. Dal Calisio proviene anche il Rosso Ammonitico, la roccia utilizzata per costruire la città di Trento fin dall’Età romana. I famosi cubetti di Porfido con cui sono lastricate strade e piazze, provengono dal lembo settentrionale dell’Ecomuseo, nel territorio di Albiano e Fornace.
Werfen Formation includes a silver-plated galena field, a lead sulphide containing a small amount of silver. In the Middle Ages, the Prince Bishop of Trento started an intensive cultivation of this deposit, summoning the best miners and silver workers from the Germanic regions (the canòpi – from the German Knappen, miners). The oldest European mining statute, Liber de Postis Montis Arzentarie written in the Codex Wangianus drawn up by Federico Vanga at the beginning of the 13th century was established to regulate this activity. Silver probably stocked the Mint of Trento, operative in those years, where the so-called “grossi" were coined.
The archaeological traces of this mining industry are impressive and constitute a unique example at European level: tens of thousands of vertical wells (the “cadìni") and miles of labyrinthine tunnels (the “canope”) cross the plateau and transform it into a lunar landscape.
The silver ended in a few centuries due to robbing cultivation, so much so that in 1637 the historian Michelangelo Mariani reported that the mines were nothing but “ancient vestiges".
The attempts to reopen crops in the last century weren’t successful, but the geologists involved in those years (first of all Gian Battista Trener) provided us with a lot of data about the deposit and about the development of galleries, which are the basis for the current research.
Between 1800 and 1900 (until the ’60s) some mines were cultivated for barite, a white mineral whose potentialities were unknown during the Middle Ages, and that is used in various fields of modern industry (such as paints, oil wells and medicine).
The story of the canòpi (from ancient German Knappen, miners) is largely unknown, and the research promoted by the Ecomuseum may perhaps clarify it in the years to come, thanks to the collaboration with an international research team.
The German technical terms in the Liber and the similarity of the archaeological traces of Calisio with those of Central European contexts confirm the hypothesis that these miners came from the Germanic territories where the extractive art was very developed.
The code provides little information about the canòpi. We know that the Prince Bishop demanded a mineral and metal tax, but for the rest he exempted miners from ordinary contributions; we know that the canòpi were subjected to the justice of the gastaldi, the Bishop’s court officials; we also know the fines for those who abandoned or damaged the mine (including hand cut). However, we have no news about the miners’ lifestyle, nor traces of interaction with the local population, which must have not been simple. There is also no data on furnaces for the mineral transformation.
Thanks to 15th and 16th century illustrations, we can get an idea of the look of the canòpi: they wore a simple tunic with a hood to protect their heads in the low mining tunnels and sometimes a “batticulo", a leather apron on which they could sit or kneel.
Even as regards excavation techniques there are still many aspects to clarify. The tens of thousands of cadìni that crushed the plateau were in part extraction wells that ended up in canòpe, used to bring the mineral outside with pulleys and to ensure the ventilation of the galleries. Some of them, however, are shallow and look like they are closed: they may be unsuccessful excavation tests or structures that have other functions, such as mineral wash.
Concerning instruments used by miners, the only findings known are those found by Trener and kept at the MUSE – Trento Museum of Science. These finds are bits protected by a grip on the long side of various sizes, wedges for breaking rocks and a hammer. From the comparison with tools found in other European mines, these finds seem to relate to the late Middle Ages or to the following centuries; perhaps they were used during attempts to reopen the canòpe rather than in the early works. According to the excavation traces visible on the walls of the tunnels, experts believe that the instrument used by the canòpi could be even more rudimentary, a kind of stocky little pick with which they could strike the rock directly, without the help of a hammer.
What we know well is how the galleries were illuminated. Many stone lumens have been found: they are simple rocks excavated and covered with animal fat and a wick. In the inner areas of the canòpe there are also burnt wood sticks, which could have been used as small torches by inserting them into the rock slits or holding them with the mouth.
Today we know about ten canòpe that have a certain development, some extended for a few kilometers: except for shorter and wider tunnels, access is only allowed if accompanied by an expert. Argentario Ecomuseum organizes guided tours on request.