Underground working in waste water - has small bore and shallow depth concrete passage roofed after driving in timber supports

摘要

The system is for making underground holes, of fairly small size near the surface of rubbish dumps. It avoids the difficulties of large open digging and can be used in many types of application. Timber reinforcements are driven in hydraulically. The roof concrete is then installed and the opening can be covered and work carried on underground. The digging can be formed by a tunnel above which is another excavation. The tunnel have a double one, the bores side by side, or superimposed.