
Martina (tunnel boring machine)

The Martina tunnel boring machine is a hard rock tunnel boring machine built by Herrenknecht AG. It is the largest hard rock tunnel boring machine in the world and has been used for drilling the Sparvo Tunnel, a part of the larger Variante di Valico project in Italy.
Specifications and operations.
The Martina has a shield diameter of 15.55 metres, an excavation diameter of 15.62 metres, a length of 130 metres, a total weight of 4500 tonnes and an annual operating consumption of 62 million kWh. The machine started work on the Sparvo tunnel in 2011, with drilling of the 2430-metre north tube completed in 2012. The drilling of the 2600-metre south tube was finished in 2013, bringing the 5-kilometre tunneling project to an end.