MCU14/0106 Appendix E - Engineering Report

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August 2004 -3- 04682104(AB)

 

Samples for ASS testing were recovered from test pits GA16 to 18 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 Guidelines’ October 1998 (Revision
4.0) of the “Guidelines for sampling and analysis of lowland Acid Sulfate Soils (ASS) in
Queensland 1998” produced by QASSIT (Queensland Acid Sulfate Soils Investigation Team).

In addition, disturbed and undisturbed (U50 tube) samples were recovered from the test pits and
boreholes for geotechnical laboratory testing (ref. Section 4.3).

Following positioning using a compass and tape survey from the flagged metes and bounds
boundaries, the approximate location of each borehole was recorded using a differential GPS
unit. However, due to the dense tree canopy, the GPS mapping was found to be inaccurate and,
consequently, the E / N coordinates have not been reported herein. It should be noted that each
test pit / borehole location was marked with a stake and flagging tape for later survey pick up,
which we recommend be undertaken, Reduced levels shown on the test pit / borehole report
forms have been interpolated from survey data supplied.

The fieldwork was carried out by a Senior Geotechnician on 21 and 22 July 2004.

Test pit and borehole locations are shown in Figure 1. Results of the fieldwork are presented in
the Reports of Test Pits & Boreholes in Appendix A, along with explanatory notes.

4.3 Laboratory Testing

Geotechnical classification testing was carried out on a number of the soil samples recovered in
accordance with the procedures described in AS 1289 “Method of testing soils for engineering
purposes”. The results are given in Appendix B and are summarised in Table Bl.

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 36 pH>/pHrox tests were conducted on samples from test pits
GAI16-18.

Based upon our assessment of the pH test results, a total of 10 samples were tested at the
Highvale laboratory of Bio-Track for ‘Chromium’ suite of tests in accordance with the ASS
Method 23 laboratory procedures.

The ASS laboratory test reports from ALS are given in Appendix C and the results are
summarised in Table C1 (Appendix C). Observations and discussion on the laboratory findings
are given in Section 7.4.

 

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

Golder Associates