Tunneling requires careful ground investigation and engineered support systems. Cut-and-cover method involves excavation and temporary roof support. The area is then covered and buried. Difficult soils or water require extensive support. Tunnel boring machines (TBMs) advance through soft ground. The circular shield supports the tunnel wall. Spoil removal is continuous as the TBM advances. Segmental linings installed behind the TBM create the tunnel wall. Rock tunneling may not require support in strong rock. Weak rock requires shotcrete and bolt support. Heading and benching advance tunnel incrementally. Safety pressurized shield protection maintains safe working conditions in wet or unstable ground. Compressed air or EPB (earth pressure balance) maintains stability. Mining methods for deep tunnels include raising and stoping. Ground water control prevents inflow and instability. Dewatering lowers water table. Grouting seals permeable zones. Ventilation in tunnels provides fresh air and removes exhaust and dust. Tunnel cross-sections must accommodate ventilation. Exits and emergency procedures are critical for safety.