In this chapter the tool consumption data of a rock cutting dredging operation are discussed. It concerns the excavation of the trench for the Sydney Harbour Tunnel, which was partially cut in rock (Hawkesbury Sandstone). The tool consumption data were compared with the wear factor F developed by Schimazek (Chapter 11.3), the SPW (specific wear rate) equation developed by Deketh (Chapter 12.5) and with the cutting- and abrasive wear rates as determined with the core cutting- (Chapter 9.7) and core abrasion test (Chapter 11.1). Also the data on the performance of roadheaders in the sandstones and siltstones of the Sydney Ocean Outfalls tunnelling operation were studied.