Simplico stretched by Sandvik

摘要

Drill and blast excavation is underway on six faces of the longest tunnel on the sprawling water conveyance system that will feed the Simplico hydro project in Brazil. The top bench of the 6,030km long bore is being opened to 7.5m high by 15m wide, the standard width of all four tunnels on the scheme. The lower bench height of the "T3" tunnel will be 7.2m to give a final height of 15.7m.Geology along all four tunnel alignments comprises gneiss with typical UCS of 200MPa. In recent months, as the excavation gets underway from the upstream and downstream portals and access tunnels a third of the way from each end, to give two faces each, the average advance has been 6m per day.