1-22276-01 site plan

Project No. 1-22276                                                                                                                               Page | 2
March, 2020
Ref: 1-22276, 2020-03-25, ASSMP VER 2
Wessel Petroleum Pty Ltd – Acid Sulfate Soil Investigation and Management Plan - Proposed Service Station Reconstruction, 52-54 Mary Street and
Weyba Road, Noosaville




Construction Techniques - ASS Treatment

Current experience suggests that one of the most effective methods that can be implemented to
limit or prevent the adverse consequences of excavation of ASS material, is the controlled
application of a suitable neutralising agent.

Various neutralising agents are available, with aglime being the most widely used product for
ASS treatment.

It is advised that this ASSMP considers that excavated material will be treated on site.
However, recommendations following are equally valid should soils be treated off site,
including at an off site facility.

Treatment of ASS should be carried out in accordance with this management plan. Validation
testing would be required to confirm neutralisation.

Table E1 presents the estimated lime dosages per cubic metre of soil to be added to the
excavated material, based on the results at the various field investigations and laboratory
analysis.

TABLE E1                DESIGN LIMING RATE
                                                                                          Factored Liming Rate
                           Depth (m)
                                                                                 (kg of CaCO3/m3 of excavated material)
Existing Pavement Gravels                                                                           0
Existing Fill and Natural Soils
- < 1.0m depth below top of natural profile                                                                    5
- > 1.0m depth below top of natural profile                                                                    13
Notes:
      1.    Depth in metres below existing level at time of investigation.
      2.    Bulk (dry) density 1.7t/m3 assumed
      3.    Lime dosing rates include a factor of safety of 1.5
      4.    100% purity (neutralising value) is assumed for the aglime (any variation must be factored accordingly).
      5.    Dosing rate calculations were carried out in general accordance with the method set out in the QASSIT
            guidelines.

It should be noted that the liming rates arrived at in Table E1 are based on the most severe
laboratory results.

Construction Techniques

The construction technique implemented during the lime application is critical and as such, the
following measures will be undertaken:-

           Only aglime (calcium carbonate) should be used, as quicklime or slaked lime is not
            considered a long term neutralising agent of sulfuric acid, and eventually may raise
            groundwater pH to unacceptable levels.
           The recommended lime dosing rates refer to a 100% pure lime product. The actual
            liming rate would need to be factored according to the product's quoted neutralising
            value in order to reach the ideal neutralising capacity.
           The aglime must be fine grained to ensure better mixing and decreased chance of acid
            leachate runoff occurring.
           The maximum time between exposure on excavation and treatment should not exceed
            18 hours. This would require all disturbed material to be treated on the day of



                                                                                                                  SOIL SURVEYS