Preliminary Studies Aimed at the Re-Opening of Pestarena Gold Mine (North-Western Alps, Italy)

Abstract

Gold, among all conventional metals subject to a progressive increase in value in the international market, has jumped powerfully into the spotlight during all economic crises. This contingency led to reconsider the dismissing process of some Italian mining sites and in particular at Pestarena- in the Anzasca Valley near Macugnaga (NW Alps) -the most important historical gold mine in the Alps. This mine site interests an area of 4 km² through about 40 km of tunnels. The orebodies are composed of gold-bearing post-metamorphic structures, represented by mineralized cataclasites and veins, often discontinuous and with complex structural geometry. Such a structural complexity makes it difficult to assume a profitable method of exploitation without a whole prospection of the deposit, pursuing the goals of safety and sustainability of the mine. In order to visualize the geometric relationships between orebodies and mine levels, it was necessary to digitalize the unique still existing mining plan, updated at the end of 1960 when the mine was closed. This process led to the creation of a 3D digital map. This has proven critical in the understanding of spatial relationships between surface topography and mine elements. The study allowed us to plan further field surveys based on new criteria that gave a better geo-mining knowledge of the site. It also demonstrates a potential interest for the exploitation of immediately exploitable gold resources and give interesting highlights on the possible future development of the mine activities.