RAISED BORE METHOD – 8.2.1.7. New Shaft Chamber and Tunnel, pp. 11-12

“. . . the raised bored construction method . . . involves drilling of a pilot hole from the surface. A boring drill rig would be assembled at the bottom of the shaft where the tunnel would terminate, and turned by a machine at the top. The boring spoils would fall into the tunnel, and would be removed as the drill is raised from the bottom of the shaft. Using the new tunnel for access, all the debris would collapse into the new tunnel and would be removed at the water treatment plant site . . . . This method would reduce the impact caused by construction in the area.”

Raised Bore:

From the Tunnel looking up the shaft: