PG-9236, 2022-10-31, Asr Ver 1

Project No. PG-9236                                                                                                                Page | 2
November 2022
Ref: PG-9236, 2022-11-01, ASSMP VER 1
Looroo Property Trust – Acid Sulfate Soil Management Plan – Proposed Residential Development, 128-132 Gympie Terrace, Noosaville




Tasks/Actions                          Investigations of ASS to date have targeted soils to a maximum
                                       depth of 3.0m below the existing ground level. Zones of materials
                                       with nett acidity above the action criteria have been identified over
                                       the site below the proposed excavation depths. The materials to a
                                       depth of approximately 1.5m have been shown by testing to not
                                       contain acid sulfate. If material below 1.5m is disturbed they will
                                       require lime treatment to neutralize acidity, to a depth of
                                       approximately 2.5 below ground level.

                                       In order to assess potential impacts and treatment requirements for
                                       ASS, the Earthworks Contractor shall prepare an earthworks
                                       schedule for the proposed construction activities prior to
                                       commencement of the construction and earthworks activities.
                                       ASS Treatment:
                                       The spoil will be removed from site and either:
                                       • treated at on-site or off-site location in accordance with the
                                           procedures given below; or
                                             −     A temporary stockpile and treatment area will be
                                                   established where all excavated material may be
                                                   conditioned (dried) and lime treated, for subsequent use for
                                                   site landscaping or general fill requirements.
                                             −     Bunding will be constructed around the perimeter of the
                                                   designated ASS treatment pad to intersect and contain run-
                                                   off from the pad during the soil treatment operations.
                                             −     A suitably sized drain or temporary retention basin will be
                                                   constructed to collect drainage water from the treatment
                                                   pad in the vent of heavy rainfall during the construction
                                                   period. This will be constructed in a manner to protect water
                                                   quality in adjacent waterways.
                                             −     Drainage water or run-off collected in the retention basin will
                                                   be tested to determine the quality of the water. If the water
                                                   quality falls outside the performance indicators (described
                                                   below), the water will be treated prior to discharge from the
                                                   site.
                                             −     The excavated spoil will be spread out in a designated
                                                   treatment area in layers up to 0.25m loose thickness. Aglime
                                                   with a neutralising value of 100% will be applied evenly over
                                                   the surface and thoroughly blended into the spoil at a
                                                   uniform minimum rate of 8kg (CaC03)/m3.
                                             −     For all disturbed material between 1.5m below ground level
                                                   and 2.5m below ground level, when incorporation of the
                                                   lime is complete, Chromium Suite validation testing of the
                                                   treated spoil will be carried out to establish that sufficient
                                                   lime has been added (and uniformly mixed) to neutralise the
                                                   acid generation potential of the spoil. The validation test will
                                                   be deemed to have passed if the net acidity is
                                                   18mol H+/tonne. A higher result will require the application of
                                                   additional lime, until a satisfactory validation result has been
                                                   achieved.
                                             −     Once lime treatment is complete, the treated spoil will be
                                                   removed from site or may then be stockpiled for later use for
                                                   landscaping or for general site fill requirements.
                                             −     Selection of the most appropriate test methods and
                                                   determination of liming requirements for neutralisation will be
                                                   the responsibility of the ASS Consultant.