Since Roman times the mountainous area of "Cirifoddi", nowadays part of the municipality of Assemini, aroused interest for its minerals, attested by archaeological findings. In 1861 the Societè Anonyme des Auts Fourneaux, Forge set Accieries, Petit Gaudet et C. bought 360 hectares of land, including the iron ore soils, and started the exploitation of the vein in 1863 under the direction of the engineer L. Gouin. The iron ore deposits of San Leone included three old mine land grants: San Leone (name given by its discoverer engineer Leone Gouin), Su Meriagu and Sant’Antonio. It was also built a railroad, 15.4 km long, for a steam locomotive, the first in Sardinia, in order to transport the material from the mine to the beach of La Maddalena. Here the shipment went on through large ships in order to reach the French foundries.
The work of ore-mining continued on the surface up to the decrease of the outcrops, and the decrease of iron price which forced the company to suspend the mining of the mineral. From 1886 until 1922 it had been made other small attempts to resume the ore mining, but with poor results due also to the high cost of the ore of San Leone mine. In 1922 it was revoked the grant and the mine passed to the State. The last attempt of exploitation dates back to 1950 with the Società Mineraria e Siderurgica Ferromin that brought to light a quantity of ore amounting to several millions of tons and it had also built an important treatment plant of the mineral. The closure of the washing area in January of 1963 anticipated just the closure of the mine. In 1970-75 the land and buildings were sold to a food industry.