RFI - Attachment E - Acid Sulfate Soil Management Plan · MCU25/0053

The highest Chromium Reducible Sulfur test result was associated with the sample taken in borehole BH3 at a depth of 3.75 m-
4 m which had a net acidity value of 128 mol H+/t.

Assuming a maximum excavation depth of 3.5 m for the single level basement, the highest Chromium Reducible Sulfur test
result was associated with the sample taken in borehole BH2 at a depth of 2.25 m-2.5 m which had a net acidity value of 90 mol
H+/t, equating to a lime treatment rate of 7 kg/tonne based on a Factor of Safety of 1.5.

5      SUMMARY
Recommendations regarding soil management are outlined in Section 5.1.

Recommendations regarding groundwater management (where required) are described in Section 5.2.

General information regarding the Acid Sulfate Soil Management Plan is provided in Section 5.3.

5.1 Soils
Based on the soil test results, it is recommended that:

»   The earthworks are managed by a reputable and suitably qualified consultant experienced in the field of Acid Sulfate Soils
    and treatment;
»   Soils excavated below RL 5 m AHD in the existing fill profile will require lime treatment;
»   As an alternative to lime treatment of excavated soils, the excavated soils may be transported offsite untreated, where
    disposed of at a suitably licenced landfill facility which is able to accept untreated Acid Sulfate Soil. The Acid Sulfate Soil
    may still require lime treatment once placed at the landfill facility which would be required to be checked.

Refer to the Acid Sulfate Soil Management Plan in Section 5.3 for further information regarding lime treatment rates and
general earthworks recommendations.

5.2 Groundwater
Where groundwater is expected or seeps into the excavation, groundwater monitoring must be carried out.

Groundwater must be monitored before, during and after earthworks for groundwater level, pH, Electrical Conductivity, and
Iron (Fe) & Aluminium (Al) content (dissolved and total analyses).

Refer to the Acid Sulfate Soil Management Plan in Section 5.3 for further information regarding groundwater monitoring.

5.3 Acid Sulfate Soil Management Plan

Acid Sulfate Soil in the form of Potential Acid Sulfate Soils were encountered in the tested soil samples based on an analysis of
the results in the PTG Geotechnical Investigation Report. An Acid Sulfate Soils Management Plan (ASSMP) has been
produced as 11 of the 18 tested soil samples breached the ‘action criteria’ as described in the ‘Acid Sulfate Soil Sampling and
Identification Manual’.

This Acid Sulfate Soils Management Plan (ASSMP) must be followed where soil disturbance below RL5m AHD and soil lime
treatment is carried out as part of earthworks for the proposed basement at the site.

If soil-lime treatment is carried out offsite, site specific ASSMP’s must be followed where they exist, otherwise this ASSMP
must be used. Discussions between the site contractor and the owner/s of the soil disposal site must be carried out. This
ASSMP should be sent to the Noosa Shire Council for potential further comments and for final approval. This should be done
before any earthworks or soil disturbance is carried out at the site.

Based on the information provided by the Client, it is understood that the proposed development will include the excavation of
a single level basement over an area of 471 m2 and two residential levels above ground. Assuming an estimated soil bulk density
of 1.7 t/m3, it is estimated that 800 t of soil will be excavated below RL 5 m AHD.




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