Appendix B - Global Stability Assessment Report

                                                  -2-
                                                                                     Job No: ME21/032

The geotechnical information in this report includes:

       Description of subsurface materials in the depth range of the boreholes in accordance with
        AS1726, including regional geology;
       Laboratory test results;
       Global stability modelling of the existing cut and fill batter slopes;
       Recommendations to improve the existing stability of the cut and fill batter slopes, targeting a
        Factor of Safety of at least 1.5;
       Recommendations with regards to long term stability of the proposed shed.

2.0 METHODOLOGY

The geotechnical investigation involved the drilling of three boreholes, designated BH1, BH2 and BH3,
across the constructed platform. The boreholes were drilled to a depth of 6m (boreholes BH1 and BH3),
and 3m (borehole BH2) using a utility mounted drill rig (Drillman GT10) fitted with 100mm diameter
augers and a TC bit.

The subsurface conditions, encountered in the depth range of the boreholes were logged and visually
classified in accordance with AS1726 by an Engineering Geologist from Morrison Geotechnic.

Pocket penetrometer tests were carried out on disturbed clay samples (curls of clay from drill augers)
and undisturbed ‘U50’ samples. Dynamic Cone Penetrometer (DCP) tests were performed adjacent to
each borehole location.

Disturbed samples were collected from the boreholes for laboratory testing. The following laboratory
testing was carried out on selected samples:

       Particle Size Distribution and Atterberg Limits (together referred to as Quality of Materials)

Following the subsurface investigation, a walkover survey of the Site was conducted. This involved
mapping and measuring features of significance to slope stability such as soil type, slope gradients and
direction, observed erosion features, surface and subsurface drainage, and the presence of irregular
surface features such as slips, slumps, hummocks, back scarps, scree debris fans or any associated
features.

All of the identified features including the subsurface conditions and the surface site features such as
the ground slope angles were used in the global stability assessment.

        2.1 Global Stability Assessment

The methodology used to carry out the assessment included a review of the information gathered during
the geotechnical investigation and site walk over performed by Morrison Geotechnic on the 4th of
November 2021, along with a review of the provided information, as follows:

       Survey plans of the Site by Focus Survey Group which included a surveyed section of the cut/fill
        platform, dated 14/10/2021;
       Site photos taken by Focus Survey Group, dated 14/10/2021;
       Level 1 Earthworks compliance Report by Morrison Geotechnic, Job No: ML21/188, dated 28th
        October 2021;
       Erosion and Sediment Control Plans by Aussie Environmental.

The global stability assessment was carried out using the commercial slope stability software SLOPE/W
incorporating the Morgenstern Price analysis method.

The geotechnical parameters used in the assessment were based on the laboratory test results of the
collected samples, and our knowledge of the performance of similar materials.

The ground surface geometry used in the global stability assessment was taken from the provided
section, and onsite measurements carried out by the Morrison Geotechnic Engineering Geologist.


Ref: 27222-rev 1                                                            MORRISON GEOTECHNIC
Mr Geoff Hussin