Excavation Category
Temporary mine openings.
Permanent mine openings, water tunnels for hydro-electric
projects, pilot tunnels, drifts and headings for large excavations.
Storage rooms, water treatment plants, minor road and railway
tunnels, surge chambers and access tunnels in hydro-electric
project.
Underground power station caverns, major road and railway
tunnels, civil defense chamber, tunnel portals and intersections.
Underground nuclear power stations, railway stations, sports and
public facilities, underground factories.