08/1491 - MCU - Detached House [As Published] · 132008.1491

All excavated soil will be stored in a bunded area by the end of the working day unless lime
treatment has been undertaken.

The bund must either be constructed from non-ASS material or from lime treated ASS material.
The bund should drain to a sump or other water collection point.

The bund floor and wall should be clay or other impermeable material to minimise infiltration of
water. The floor should have a hydraulic conductivity of less than 1 x 10% m/d fora minimum depth
of 400 mm or have an equivalent resistance to the passage of drainage water. Compaction is likely
to be required to achieve this level of hydraulic conductivity.

Any water trapped within the bund or excavation site must be pH tested prior to discharge.
The pH must be adjusted to be within the range of 5.5 to 7.5 prior to discharge. The use of
calcium hydroxide (builders lime) is suggested for this: purpose.

If a bund is impractical smaller stockpiles can be covered with plastic sheeting or similar materiais
to exclude rainwater. The stockpile must not be located in a runoff flow path.

46 Treatment Pad Design

If lime is incorporated with soil at a specific mixing area then the treatment pad should be bunded (as
specified in section 4.5).

If the pad floor is constructed from untreated acid sulfate soil then the floor must be lime treated as
specified in section 4.1.

Validation testing of lime treated samples will require time for sampling, sample transport to a laboratory,
sample drying and analysis. This process can easily require 5-7 working days. The treatment pad and any
storage areas need to be sized to accommodate treated soil that remains to be validated.

47 Exposed Cut Surfaces

If excavation areas will be left exposed then these should be capped to minimise oxidation of sulphidic and
acid soil. The minimum depth of limed capping should be 800 mm.

4.7.1 Vegetated Cover

if the excavated area is to be revegetated then topsoil should be placed at the surface. The lime treatment
rate is conservative and an alkaline soil pH is expected. This may not suit re-vegetation and could result
in nutrient deficiency (eg. Zn, Fe, Mn & P). To avoid this problem it is recommended the existing 0-200 mm
soil layer is stripped from the site and stockpiled. This assumes the 0-200 mm soil layer is currently
vegetated, non-saline, well oxidised and non-sulphidic. Care must be taken to restrict the topsoil removal
to this depth to avoid sulphidic material deeper down.

The final placement over the cut material should be:

0-200 mm replaced topsoil, uncompacted for revegetation (existing pH/acidity)

200-400 mm limed cut material, low level of compaction to allow for drainage and root
penetration (strongly alkaline, no acidity)

400-1000 mm limed cut material, high level of compaction to minimise oxidation and deep

drainage (strongly alkaline, no acidity)
4.7.2. Non-Vegetated Cover
\f the excavated area is not to be revegetated then no topsoil is required.
The final placement over the cut material should be:

0-800 mm limed cut material, high level of compaction to minimise oxidation and deep drainage
(strongly alkaline, no acidity)

Bio-Track Pty Ltd 3