Hills Metalliferous

Hills Metalliferous are main and the greatest system hilly and mountainous dell'Antiappennino Toscano. The territory of the hills is shaping up in the centre-west of Tuscany, affecting as many as four provinces in the south-eastern province of Livorno, the southern part of the province of Pisa, the south-western province of Siena and the north - western province of Grosseto. The area is extremely rich in underground resources mining of various kinds, principally between the province of Pisa and Grosseto, are also sources of geothermal energy that occur in the form of soffioni boraciferi.