In the second half of the twentieth century in the territory of Gerrei and partly also in Sarrabus some deposits of fluorspar, a mineral used in some sectors of industry, in the production of particular plastic materials (Teflon), in the refrigerant industry (Freon), in the glass industry and in the medicine industry, were identified and studied. In the early 1990s a good deal of the propellant gases, consisting of fluorine, chlorine and other chemicals, caused a crisis in the value of fluorspar and thus the Silius mine. This passed from the private company that had operated it since its inception to the Region of Sardinia, the current owner, the latter of which has in recent years initiated a series of projects aimed at rehabilitating and relaunching the ore mining activities, which are currently suspended, despite the ascertained presence of more than 2 million tons of extractable ore. The deposit, consisting of fluoride, barium and lead ores, stretches for several kilometers and covers an area just under 600 hectares wide, underground reaching depths of more than 350 meters, beyond which mineralization tends to be exhausted. Over the decades a mesh of tunnels and shafts has developed articulated in two large sites; Muscadroxiu and Gennas Tres Montis, with several nuclei inhabited by workers, among them Polish personnel specialized in digging shafts. Despite the “young” age of the mine, whose work began in 1968, that of Silius remains among the most interesting and in some ways traditional mining facilities nationwide. Access to the underground, in fact, is through shafts and not with the help of road ramps. Inside, new mining techniques, tools and machinery have been devised and tested, all aimed at improving the efficiency of the work and the training of the staff consisting, perhaps, of Italy’s last miners, just under 150. While mining took place on the Gerrei hills, on the outskirts of Assemini the ore from Silius was being processed to be separated from other minerals and impurities.
