Vipiteno mine, Italy – underground mining for marble

Abstract

There is increasing emphasis on the underground mining of industrial minerals in the UK and Europe. A recent example is Vipiteno mine in Northern Italy, whose products are crushed and powdered translucent white marble. The marble is in seams with minimal dark mineral impurities, about 20–30 m thick, dipping at about 45–50° extending about 1·5 km along strike and several hundred metres down dip. The mine is in mountainous terrain subject to heavy winter snowfalls. Production strategies have been developed using high and low elevation underground mines. A combination of large cross-section development and bulk mining methods has been adopted, notably open stoping with drawpoint extraction. Stopes excavated to date are up to 50 m high x 20 m true thickness x 80 m along strike. Higher stopes are planned. The rock mass is of good quality, with a GSI rating of up to 70 and a Q rating of up to 15. It is dominated by very continuous bedding, which controls hanging-wall stability. In some locations, faulting also exerts control on hanging-wall stability. The mass strength is about 24 MPa and the in situ stresses are estimated at 5–10 MPa. Pillars have been designed conservatively and the major design challenge is the hanging-wall stability. Extensometer instrumentation has been installed to monitor hanging-wall stability in some early stopes and these indicate stable behaviour to date. It is planned to modify current mining methods to minimise development costs by simplifying and eventually eliminating drawpoints.