SECTION 3 Groundwater Effects Assessment – WUG Access Tunnel 11 Aquifer Parameters No site-specific testing has been undertaken to characterise the properties of the rock through which the WUG access tunnel will be driven. These geologic units are, however, the same as those mined in Waihi and have been previously characterised as shown in Table 1. Table 1 Aquifer Hydraulic Properties Hydraulic Conductivity Storativity Material Max (m/s) Min (m/s) Geomean (m/s) Max Min Shallow Aquifers Ash / Alluvium 1 x 10-4 1 x 10-7 0.3 0.1 Ignimbrite 1 x 10-5 1 x 10-8 0.01 0.001 Rhyolitic Tephra 1 x 10-6 1 x 10-7 0.1 0.05 Deep Aquifer Andesite Surface 3 x 10-5 2 x 10-6 5 x 10-6 0.3 0.1 Andesite to 50 m Depth 7 x 10-9 6 x 10-9 0.01 0.005 Andesite to 100 m Depth 6 x 10-7 6 x 10-9 3 x 10-8 0.01 0.005 Andesite 1 x 10-5 1 x 10-8 0.05 0.001 For the purpose of the groundwater effects assessment that follows, values within the identified ranges have been adopted. 3.3 Conceptual Groundwater Model A conceptual hydrogeologic model for the WUG access tunnel along the alignment is presented in Figure 8. In summary, based on previous studies and what we know about the area, the model assumes that the initial part of the decline is already dewatered from underground mining. Figure 8 WUG Access Tunnel Conceptual Hydrogeological Model
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