Appendix D - Geotechnical Report

5.1.3        Proposed Lot 3
Proposed Lot 3 contained an existing residence to the south off Black Mountain Range Road. We
understand that the building would be maintained in situ as part of the development, and no additional
building envelopes are planned elsewhere on the proposed lot.
The topography on proposed Lot 3 was dominated by a rounded spur, which generally dipped down to
the north at about 10°, and the flanks were relatively steep at about 25°. The block would extend via a
‘dog leg’ to the north-east, to the frontage with the Bruce Highway corridor, with a small dam also
contained in this part of the site.
The existing residence was of one storey height with masonry brick walls and a tiled roof. The walls were
mostly in good alignment, however some cracking was present to the north-east and north-west (in the
north facing wall). The cracks were persistent from ground to window sill level, with an aperture of about
1 mm to 3 mm. An exterior concrete apron around the perimeter had dropped about 20 mm to 30 mm,
and separated ≤40 mm from the building walls. This was most prevalent to the north, east and west of
the building. Partially in-ground concrete water tanks were surrounded by concrete surfacing off the
eastern gable. The tanks had been sutured in a number of locations, and the adjacent surfacing was
cracked in several places. Additionally, the surfacing appeared to have slid laterally along the ground
surface to the north-east.
The wastewater pipe from the bathroom in the north-eastern corner of the house appeared to connect
to a broken clay pipe, which in turn extended under the house through the slab. It was not possible to
determine the position of the septic trenches for the property at the time of our walk-over.
Downslope of the house to the north-east, there was a fenced flat pad (presumed to be a former tennis
court). This was estimated to have involved historic earthworks of about 1.4 m depth of cut, and up to
1.2 m height of filling downslope. The cut was subvertical, and exposed about 0.6 m of residual soil (silty
clay with gravel) then grading to extremely weathered (XW) material of hard, silty clay and dense, clayey
gravel. Reference images of proposed Lot 3 are presented below in Text Figures 7 & 8.




 Text Figure 7: Site layout (courtesy MWA) existing residence (centre) and general view looking north
                                           over spur (RHS)




Geotechnical Investigation
10 June 2026 | 26073-001-Rev0                                                                             8