This mine in the Oridda valley was also opened to extract calamine, a mix of zinc silicate and zinc carbonate, whose prophet was the Franco-Belgian engineer Giovanni Eyquem. Spurred by the example of the Planu Sartu mine, where that ore was filling the pockets of the Malfidano company, many prospectors started wandering up hill and down dale in this part of the lglesiente in search of traces of this 'new' zinc-bearing ore. Fortune favoured the French married couple Garnier, who with their Societe Civile d'lglesias obtained in 1873 the mining concession for the lands at S'arcu de sa Duchessa. Theirs was presumably a speculative move, as a few months later they sold their rights to the Societe des Mines et Fonderies de La Vieille Montagne, which aimed to rival the Malfidano company of Buggerru in the zinc market.
The Belgian multinational invested heavily in the new venture and within three years increased the output of high-grade run-of-mine zinc ore from just over 3,000 tonnes to eight times as much. Initial difficulties arrived with the outbreak of World War I (1915), when it became impossible to transport the ore to the Belgian foundries. Another impasse occurred in 1936, when the Vieille Montagne, on account of being a Belgian-owned company was hit by the Italian government's reaction to the sanctions imposed by the League of Nations: it was forced to assign all its Sardinian mining holdings to a State company, the Societa Anonima per il Rame Italiano (since at the worksites known as ribasso Maremma copper-bearing ore had been discovered), subsequently replaced by the newly-constituted AMMI (Agenzia Minerali e Metalli ltalianiJ.
The war and the difficult post-war period proved lethal for the mine: activity was gradually reduced and finally ceased in 1971.