David Lees and Associates were appointed Brandrll Limited to determine the blasting efficiency and slope stability of a number of major motorway cuttings near Gympie in Queensland.
The excavations were in very broken andesitic lava requiring 4m batters at 60 degrees. A review was carried out of the geological information to determine the most appropriate slope design and potential needs for support.
A further review was carried out of the blasting, with particular regard to the presplit, and its effect on overbreak and stability. The work was successful in resolving the dispute and stabilising the slope.