Response to Information Request - Received on 19/04/2012 · OPW11/0335

                                                                                          BUT           L.   E     R




SECTION 4. INVESTIGATION RESULTS

4.1       Results


The subsurface conditions encountered in the bores are given on Bore Report Sheets included in Appendix A,

using classification and descriptive terms defined in the accompanying notes. Laboratory test report sheets are
included in Appendix B.


4.2       Subsurface Conditions


For a description of the stratigraphy encountered in the bores, the Bore Report sheets should be consulted.

However, in broad summary, the subsurface conditions encountered in the bores generally comprised a surface
layer of either fill material (in Bores 1 to 4)that varied up to a maximum depth of 0.8m, or silty sand (in Bores 5
and 6)to a maximum depth of DAm. In Bores 1 and 2 only, the fill was underlain by natural, dark grey-brown

silty clays that were underlain in tum by silty sands that were indurated below 2m depth. In Bores 3 to 6, the
surface fill or silty sand layer was underlain by sands.


4.3       Groundwater

Free groundwater was encountered during the drilling of four of the six bores at the depths/RLs given in Table 1.
It should be noted that groundwater levels can vary seasonally and with prevailing weather conditions.

                    Table 1: Observed Groundwater Depths/Reduced Levels During Drilling

                                                   Groundwater O’bse~ations
                                        Bore
                                                   Dep,th         Reduc tll v i---
                                                            ..-   -            ---




                                                    O.S’              RL 2~3
                                        -   ---   -->--               ------




                                            2       0.8               RL2.3m
                                            3       1.5               RL6.0m
                                            4             Not encounter d

                                        . .



                                            ~_,-’ -~5’~~~~1;~; o.f~ ~!d~’-"
4.4       Laboratory Testing


4A.1      Screening Tests

Screening tests were undertaken on all soil samples collected from all bores. The screening tests comprised
two small sub-samples of soil; one mixed with approximately 20 mL of distilled water, and the other mixed with

approximately 20 mL of hydrogen peroxide, buffered to a pH of 5.0 with sodium hydroxide.


Slurry pH was measured with a calibrated pH meter.                The pH of the distilled water/soil slurry (pHF) was
measured approximately one hour after mixing, whilst the pH of the hydrogen peroxide/soil slurry (pHFOx)was
measured approximately one to two hours after mixing.




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Project No. 07160                                                                                         18 June 2007