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

October 2007                                   -3-                            077682076(AB)


Samples for ASS testing were recovered from boreholes BH5 and BH8 at 250 mm intervals to
3 m depth. ASS sampling protocols in the field were conducted to minimise oxidation prior
to laboratory testing and followed the Queensland Sampling Guidelines1 October 1998
(Revision 4.0) of the “Guidelines for sampling and analysis of lowland Acid Sulfate Soils
(ASS) in Queensland 1998” produced by the Queensland Acid Sulfate Soils Investigation
Team (QASSIT).

The approximate location of each borehole was recorded using a hand-held GPS unit having
an accuracy of ± 3 m. Borehole positions are shown in Figure No. 1. Reports of boreholes
are presented in Appendix A, along with explanatory notes. Easting and northing coordinates
recorded for each borehole location are shown on the reports, together with ground surface
elevations interpolated from survey data provided.

Borehole drilling fieldwork was conducted on 4 and 5 October 2007 in the presence of a
Senior Geotechnician from Golder.

3.3     Geotechnical Laboratory Testing

Geotechnical classification testing was carried out on samples recovered from the boreholes at
the Bokarina laboratory of Geotech (S.C.) Pty Ltd in accordance with the procedures
described in Australian Standard AS1289 “Method of testing soils for engineering purposes”.
The results are given in Appendix B and are summarised in Table 1, Section 4.4.

3.4     ASS Laboratory Testing

Tests to assess field pH and pH after oxidation (with 30% hydrogen peroxide solution
buffered to pH>4.5) were conducted as an initial screening procedure to help select samples
for laboratory analysis. A total of 24 pHF/pHFOX tests were conducted and the results are
shown in Table C1 (Appendix C)

Based upon our assessment of the pH test results, a total of 6 samples were sent to Australian
Laboratory Services (ALS) at Stafford for ASS testing comprising the Chromium suite of
tests in accordance with ASS Method 23 laboratory procedures. pH was also measured in
KCl suspension by the analytical laboratory on all samples submitted for testing.

The ASS laboratory test reports from ALS are given in Appendix C and the results are
summarised in Table C1. Observations and discussion on the laboratory findings are given in
Section 5.




1
 Guidelines for Sampling and Analysis of Lowland ASS in Queensland, Qld ASS Investigation Team
(QASSIT), Revision 4.0, October 1998.



                                     Golder Associates