Supporting Technical Assessments

Oceana Gold New Zeland Limited Hydrogeology Support for WKP Underground Updated Conceptual Model Figure 2-1 Location of boreholes with hydraulic testing data To defined as the starting point for the packer analysis. This report compiles a reasonable amount of information and states limitations and difficulties during the field testing. -testing program implemented by Golder indicates: 12 tests have been completed using a single pressure step (constant pressure test). 23 tests were completed following all pressure steps. 1 test was not fully completed due to a packer burst. 2 tests were poorly performed due to limitations of equipment or operational difficulties Packer tests were analyzed using calculation spreadsheets developed by FloSolutions. Spreadsheet-based calculation of Lugeon values was completed for each pressure step in the packer test. The resulting Lugeon patterns were then compared to the typical flow patterns: Laminar Flow, Turbulent Flow, Dilation, Wash-Out or Void Filling. The Lugeon pattern and interpretation of flow type is used to select the appropriate pressure step or steps for use in calculation of hydraulic conductivity (K) using the method of Houlsby (1976). The selected pressure step or steps for each test were evaluated using two types of numerical solutions to obtain hydraulic conductivity: Theim Equation (1906): used for tests with interpreted radial laminar flow. Hoek and Bray (1974): used for tests in fractured rock. In some tests, all five steps were not completed in the field, and it was not possible to clearly define a pattern of Lugeon using the methodology proposed by Houlsby. In these tests the single available pressure step was used (in case of constant pressure tests), or professional judgement and experience were used to select and appropriate pressure step. Results are described in Section 3.1.

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