In the Sinis of Cabras there are numerous calcarenite quarries. Some are located very close to the coast for the cost-effectiveness of transporting stone materials by sea, given the difficulties of land transport due to the lack until recent times of passable roads; among these can be mentioned the so-called “Sala da ballo” (Ballroom), located north of S. Giovanni di Sinis, the quarry of Punta Maimoni, those of Corrighias, Su Crastu Biancu, Is Aruttas, Su Bardoni and Muras. Others are instead found further inland in areas of vast rocky outcrops, as is the case in particular at the localities of Sa Pedrera and Procaxius.
The traces of working still visible document the extraction technique used, common to other ancient deposits: the quarrying activity involved the excavation, with the use of metal picks, of grooves between 5 and 15 cm wide, progressively narrower towards the bottom and with a V or U section, which made it possible to delimit blocks, even of considerable size, freeing them on the lateral faces; the detachment of the lower face was achieved through the use of wedges, in metal and perhaps also in wood, driven deep into the rock with the aid of heavy hammers. The progressive removal of the blocks created quarry fronts from which the subsequent extraction continued, both in depth and in extension. The dating of the Sinis quarries is still uncertain, but it is possible to hypothesise, at least for some of them, an exploitation starting from ancient times.
(images taken from “I quaderni a.m.p 02: storia e archeologia”, p. 55)