David Lees and Associates was appointed by the North Side Storage Tunnel Alliance of Transfield, Sydney Water, Connell Wagner and Montgomerey Watson to provide technical advice for the drill and blast excavation of the shafts at Scotts Creek and Lane Cove. This included the preparation of a Blast Quality Plan and submission to the Environmental Protection Agency. 

The two shafts were important parts of a major sewerage overflow capture scheme along the north shore of Sydney Harbour. The shafts provided access and ventilation at the east end of the scheme. Both shafts were located in National Parkland within close proximity to residential housing, schools and other existing sensitive structures. The work included the implementation of trial blasting, and on going blast designs and site monitoring of noise and vibration.