Reference Document - Acid Sulfate Soil Management Plan (For Stamping) MCU25/0053 & OPW25/0074

        Reporting:                The site contractor should keep lime dockets to ensure that a record is kept onsite of all lime quantities
                                  brought on to site – a copy may be taken to prevent fading of original invoices/weighbridge dockets
                                  as required.

                                  All records will be available for inspection on site during earthworks.
        Corrective Action:        If Phase 2 daily groundwater monitoring indicates a change in acidity conditions during earthworks,
                                  groundwater treatment may be required. In this case, a suitably qualified and competent groundwater
                                  consultant should be contacted for further information.

                                  If Phase 3 sampling indicates that the excavated material has not been fully neutralised, additional
                                  lime will be applied based on the Phase 3 test results until the material passes subsequent validation
                                  testing.
        Lime Guard Layer:
                                                                                                    Acid Sulfate Soil
                                                                                                    (300mm layer)
                                                                                                                          Bund Wall
                                          Lime Guard Layer
                                          (5kg/m2/300mm
                                               layer)




                                                                                                                        Leachate Drain

                                         Compacted
                                         Clay Layer
                                       (300mm thick)


                                                               Figure 1 – Acid Sulfate Soil treatment pad design

        Validation Testing:       »       Validation/audit testing must be carried out once lime is thoroughly mixed with the Acid Sulfate
                                          Soil at the recommended rate. This testing will ensure all acidity has been neutralised and excess
                                          neutralising capacity is available and reported. Dockets for lime (neutralising agent) must be kept.
                                          An audit report shall be written at the completion of earthworks by a competent and qualified
                                          consultant.
                                  »       The recommended laboratory method to ensure there is sufficient lime to neutralise the acidity is
                                          the Chromium Reducible Sulfur (SCR) method. On the basis that no more than 471 m3 of soil will
                                          be disturbed below RL 5 m AHD, a total of three SCR tests are recommended to be carried out on
                                          excavated and lime treated soil. The final number of tests will be dependent on the total
                                          disturbance volume below RL 5 m AHD based on the following (<250 m3 = two samples; between
                                          250 m3 and 500 m3 = three samples, >500 m3 and <2% Sulfur = three samples, plus one sample
                                          per additional 500 m3).
                                  »       All soil samples will be collected by a qualified person and delivered to an approved laboratory for
                                          analysis. A minimum factor of safety of 1.5 is to be used to ensure that there is an excess amount
                                          of acid neutralising capacity in the lime treated soil, and to account for incomplete lime mixing.
                                  »       It should be noted that the results produced from validation testing may reveal acidic soils or soils
                                          with excessive lime content (an excessively alkaline soil). Proper care taken during soil lime
                                          mixing should ensure that this risk is reduced.
                                  »       An Acid Sulfate Soils ‘closure’ report will be required in accordance with the ‘Queensland Acid
                                          Sulfate Soil Technical Manual – Soil Management Guidelines Ver 5.1’ (Qld Government, 2024)
                                          after the earthworks are complete.


       5.3.3 REFERENCES
       Australian Government, 2018. ‘National Acid Sulfate Soils Guidance – National acid sulfate soils sampling and identification
       methods manual, June, 2018’. Department of Agriculture and Water Resources, Canberra ACT. CC BY 4.0.

       ANZECC & ARMCANZ, 2000. ‘Australian and New Zealand Guidelines for Fresh and Marine Water Quality – Volume 1, The
       Guidelines’. National Water Quality Management Strategy Paper No 4, Australian and New Zealand Environment and
       Conservation Council & Agriculture and Resource Management Council of Australia and New Zealand, Canberra.

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Document Set ID: 24149759
Version: 1, Version Date: 26/09/2025