Mine monitoring

A few kilometres from Tarvisio, in the north-eastern corner of Italy, lie the Raibl mining complex and the village of Cave del Predil.

It is a very old sphalerite and galena mine, developed over centuries of activity into an intricate system of tunnels extending for more than 150 km and reaching depths of over 500 m below the surface.

After a series of events, the mine closed definitively in the early 1990s.

The Friuli Venezia Giulia Region, which owns the complex, therefore designed a complex safety plan that provided for the controlled flooding of part of the mine, to a height of about 300 m from the bottom, up to the 13th level, where a gently sloping tunnel of about 5 km drains the water coming from the upper levels and the overflow from the lower ones into a parallel valley at a lower elevation. The planned works, including the reinforcement of the main shaft and service tunnels, lighting, and an emergency pumping station of over 1.5 MW, were carried out by the contractor Vidoni S.p.A. of Udine.

The drainage tunnel, known as the Bretto tunnel, was dug at the end of the 19th century. It is about 2 m wide and about 3 m high on average, with a significant part occupied by water. A stretch of over 1.5 km was assessed as geologically critical because it crosses faults and layers of schist that are particularly fragile and prone to movement and collapse. Despite the reinforcements made over the years (often in concrete and steel ribs), the stability of the tunnel is put at risk by the instability of the rock and the movement of the faults. It was therefore considered appropriate to build a continuous electronic monitoring system that would promptly indicate any sudden collapse and record the extent and speed of movement over time.

CASE HISTORY: Cave del Predil Mine

OMNIAEVO DIVISION: AUTOMATION

MANAGER: MASSIMO BELLUZ

CUSTOMER: VIDONI SPA

USER: REGIONE FVG DATA

DELIVERY: 2009

LOCATION: CARNIA/FVG

ABSTRACT: design and implementation of a continuous monitoring system that promptly detects sudden collapses of the tunnels and records the extent and speed of movement over time.