The 1 500m long pressure tunnel starts in Angolan
territory at the eastern end of the Diversion Weir. After an initial
downward slope of 1:17.5 degrees, the tunnel flattens slightly, reaching
its lowest point 1 200m further, where it reaches the Palmwash ravine.
From here the tunnel grades upwards (1:7.2) until it reaches the Surge
Headbay.
Tunnel Supports:
Various methods of support were used during the
excavations with steel mesh, rockbolts and prestressed cables, shotcrete
and gunite being the methods used most frequently.
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