22244-002-Rev1 Barina Ct

Mark Kussrow                                                                                                    22244-002-Rev1
C/- CadCon Surveying & Town Planning                                                                           26 February 2024

3.0          DESCRIPTION OF EXISTING CONDITIONS
3.1         Geology
The 1:100,000 scale Gympie Surface Geological Map 1 (Ref. Text Figure 5 below) indicates that the site is
underlain by materials derived of the early to middle Triassic age Kin Kin Beds (blue-green shading),
which are described as “commonly cleaved and commonly kinked mudstone…” The Australian
Stratigraphic Units Database describes the Kin Kin Beds as “arenite, argillite and phyllite.” Quaternary
age alluvial deposits are mapped around a creek along the southern boundary of the site.




                                                                                       Approx. Site Location




Text Figure 5: Extract of Gympie Surface Geology Map

3.2         Subsurface Conditions
Detailed descriptions of the subsurface conditions encountered in the boreholes are provided in the
borehole reports attached, along with definition sheets which describe terms and abbreviations used on the
reports. DCP results are also provided on the borehole logs. Subsurface conditions encountered in the
boreholes are summarised as follows:

            Fill/Topsoil – comprising mostly stiff to very stiff, silty and gravelly clays of medium plasticity to
             depths between 0.9 m and 3.3 m BGL; then
            Natural Soils – very stiff to hard, silty and gravelly clay of medium to high plasticity to depths
             between 2.1 m and 7.5 m BGL (borehole BH1 termination depth).
            Extremely Weathered (XW) Materials – borehole BH2 intersected hard, gravelly clay of medium
             plasticity which was noted to be tending towards very low strength phyllite to the termination depth
             of 3.5 m BGL.

Standalone DCP1 which was conducted in the bed of the drainage line below the main dam wall toe
indicated a stiff/medium dense (or stronger) profile to 2.2 m BGL, becoming very stiff/dense (or stronger) to
the termination depth of 2.4 m BGL.

Groundwater inflow was encountered below about 3.1 m BGL in borehole BH1, with no groundwater
encountered in borehole BH2.




1
    State of Queensland, Dept. of Natural Resources, Mines and Energy, Gympie Surface Geology, Sheet 9445, 2018




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