Appendix 5. Geotechnical Engineering Report [As Published] · 132007.2399

October 2007                                               -4-                    077682076(AB)


4.0         INVESTIGATION FINDINGS

4.1         Preliminary ASS Assessment

Available geological information2 indicates that the site is underlain by Quaternary age strata,
being across the boundary between sand dune and coastal swamp deposits.

As shown in Figure No. 2, Extract of ASS Map, published ASS information3 covers the
subject site, with classifications given as follows:

•       S – Low-lying south-western area. “Land where ASS occurs within 5 m of the surface”.

•       LP/LP5 – Remainder of site. Land with a low or negligible probability of ASS
        occurrence, including ground above RL 5 m AHD.

Following the desktop study, and prior to the fieldwork, a walk-over survey of the site was
conducted by a Senior Geotechnical Engineer from our Maroochydore office on 25
September 2007. The walk-over survey was carried out in the presence of Mr Alan Starkey,
who provided anecdotal evidence regarding the site.

As mentioned in Section 2.0, a large part of the site is gently sloping land, where sandy soils
are exposed at the ground surface. The low-lying south-western part is approximately level or
has been filled and includes areas of melaleuca vegetation, which frequently indicates ‘wet’
ground and an increased risk of ASS occurrence (below RL 5 m AHD). Surface water drains
from this low-lying area via a system of drains and lakes towards the south.

Our preliminary assessment generally concurs with the published data in that potential ASS
(PASS) are likely to occur at shallow depths from natural ground level across the south-
western part of the subject site. No surface indications of previous oxidation of ASS (ie.
actual ASS or AASS) were observed; ie. we did not see any areas of iron staining, jarosite or
scalded vegetation.

4.2         Subsurface Conditions

The subsurface conditions encountered in the boreholes drilled across the subject site are
summarised below under classifications of inferred origin. Section A-A, Figure No. 3, shows
a cross-section through the site, overlain with subsurface conditions encountered in selected
boreholes.




2
    1:100,000 Geological Map, GYMPIE SPECIAL, Sheet 9445 & Part 9545, DME, 1999
3
    1:100,000 Redcliffe to Teewah ASS Map 2, DNRM, 1999




                                               Golder Associates