J000154-001-R-Rev0_ASS Investigation Report · RAP15/0034

J000154-001-R-Rev0                                                                                  November 2015


6.6        Quantitative Soils Analysis
Table 3 below shows the ASS action levels adopted in Queensland. These categories are used to identify
whether action / management of ASS spoil is required, based on ‘net acidity’. For major fill works and
disturbances of more than 1,000 tonnes, an action criterion of 0.03% S equivalents (18 moles / tonne) is
adopted for all soil types; and was adopted for this investigation.

Table 2: ASS Action Criteria

                                                                                          Action Criteria
                                                   Action Criteria
                                                                                     > 1000 tonnes disturbed
            Type of Material                   1-1000 tonnes disturbed
                                                                                     (and major fill projects)
                                              Existing + Potential Acidity           Existing + Potential Acidity
                                                                                Equivalent sulfur Equivalent acid
Texture range               Approx. clay Equivalent sulfur Equivalent acid
                                                                                %S oxidisable     mol H+/ tonne
McDonald et al. (1990)      content (%) %S oxidisable      mol H+/ tonne
                                                                                (oven-dry basis) (oven-dry basis)

Coarse Texture
                                 ≤5             0.03                 18                0.03                18
Sands to loamy sands

Medium Texture
Sandy loams to light           5 – 40           0.06                 36                0.03                18
clays
Fine Texture
Medium to heavy clays           ≥40             0.10                 62                0.03                18
and silty clays
Results of quantitative analysis carried out are summarised in Table B1, attached. Laboratory result
certificates are included in Appendix B.
Results of the 12 samples analysed are summarised below:

     All 12 samples returned Titratable Actual Acidity (TAA) results below the Action Criteria of 18 mol H+/
      tonne (0.03%S), ranging between 2 mol H+/ tonne to 7 mol H+/ tonne.

     6 samples within the fill material returned Oxidisable Sulfur as SCR at levels below action criteria with
      values ranging from <0.005 %S (Laboratory Level of Reporting (LOR)) up to 0.017 %S (11 mol
      H+/tonne).

     6 samples within the natural material (below 2 m BGL) returned Oxidisable Sulfur as SCR at levels above
      the action criteria with values ranging from 0.086 %S (54 mol H+/tonne) up to 0.35 %S (220 mol
      H+/tonne).

     pHKCl values did not exceed pH 6.5 and as such, no samples were subjected to analysis for acid
      neutralising capacity (ANC).

     No samples returned pHKCl values of less than pH 4.5, and as such no further analysis for retained
      acidity (SNAS) was carried out

The test results indicate that negligible levels of actual acidity were present in the samples analysed.

Results of SCR tests indicate that oxidisable sulfur is present at high levels within the natural soils (generally
below 2.0 m bgl) across the site. However, results indicate negligible to low levels present within the fill
materials across the site.
Of the 12 samples analysed, net acidity exceeded the appropriate QASSIT ‘Action Criteria’ (for bulk
earthworks) in all samples collected within the natural materials (below 2 m bgl).




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