13. Existing DMP (2006)

 Representative samples, at 500mm depth intervals in each of the boreholes (a total of
28 samples), were assessed by Chromium Reducible Sulfur (CRS) and Total Actual
Acidity (TAA) tests. The CRS test provides data on sulfidic acids, without influence
from organic acids and quantifies the oxidisable sulphur present in the soil. The TAA
measures the existing acidity of the soil prior to the oxidation of any sulfidic material
(Soil Survey 2006).


 The CRS test results ranged from 0.02 to 0.13 %S. Of the 28 samples tested, 17
samples returned CRS results equal to or in excess of the QASSIT Action Level of
Oxidisable Sulfur of 0.03%S (Queensland Acid Sulfate Soils Investigation Team
(QASSIT) Guidelines for Sampling and Analysis of Lowland Acid Sulphate Soils
(ASS) in Queensland (October, 1998)). Most of these samples containing elevated
levels of oxidisable sulphur occurred in boreholes BH1 (four (4) samples) and BH2
(seven (7) samples), with three (3) samples present in each of boreholes BH3 and
BH4. According to the QASSIT Guidelines, soils containing oxidisable sulphur, at
0.03%, require treatment with lime in order to neutralise the acid that could
potentially be produced by the soil. These 17 samples were subjected to further
analysis (Acid Neutralising Capacity testing) to determine the amount of carbonate
material available in the sample to act as a self-buffering agent (Soil Survey 2006).


 The TAA test results show that there was no actual acid present in the treated
samples with zero value reported in all cases i.e.28 No. test, as shown on the
laboratory test certificate (Soil Survey 2006).


 Acid neutralizing Capacity (ANC) is a measure of the soil s inherent ability to buffer
acidity and thereby resist the lowering of the soil pH. Acid neutralizing Capacity
(ANC) was carried out on the seventeen (17) samples described above.              These
samples returned calcium carbonate equivalent (CaCO3 Eq.) values between 0.55%
and 1.51% (Soil Survey 2006).


 These results indicate that there is ample self-buffering capacity present in the
soils to effectively neutralise any acid that could potentially be produced. Therefore
we recommend that no lime treatment would be required on the samples tested
during this investigation (Soil Survey 2006).


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