SECTION 3 Site Investigations & Results C:\D Data\GWS C Drive\GWS\Client Files\1344 OGL - WKP\4 Deliverables\WKP Final Draft Report\June Report\WAI-985-000-REP-LC-0030. Final_Rev_0.docx 12 3. Site Investigations & Results 3.1 Methodology There have been a number of site investigations undertaken that have assisted in characterising the hydrogeologic conditions in the area of the Wharekirauponga deposit and the groundwater catchment as a whole. This information includes: • Characterization of the geologic conditions though numerous exploration drill holes. • Verification of the surface geological conditions through exposure mapping. • Geophysics to identify lithological contacts • Analysis of rockmass defects from geotechnical core logging and zones of water loss during drilling. • Installation of shallow piezometers to assess vertical hydraulic gradients. • Installation of deep vibrating wire piezometers. • Undertaking permeability testing on shallow and deep geologic units. • Flow gaugings of the Wharekirauponga and adjacent catchments. • Collection of surface water samples and groundwater samples for dating and chemical analysis. A particular emphasis of the investigation has been to understand the level of groundwater - surface water interaction that occurs naturally in the catchment so that further assessment can be made to understand how this might be affected by dewatering of the orebody. A summary of the results of these investigations is included in the following report section 3.2 Geologic Characterisation It is estimated that there has been some 116 drill holes and 47,600 m of exploration drilling undertaken to characterize the geological conditions and define the economic extents of the orebody. This information has been collected in the form of continuous core from drilling that has been logged geologically and geotechnically and then incorporated into a computergenerated geologic model. This geologic model then forms the basis for undertaking the groundwater effects assessment once hydraulic properties have been assigned. Some of the key observations from the core is that: • On the whole the rockmass has the textural appearance of being low permeability i.e. there is an absence of fractures, particularly iron stained that would indicate the movement of groundwater. • The main EG veins are noted to be banded quartz dominated with little evidence of open voids, vugs or boiling textures that might indicate high permeability or significant groundwater movement. • The T-Stream main veins are generally more fractured and oxidised with some evidence of groundwater movement having taken place. • The stockwork systems consists of a lattice of crosscutting veins that have a generally more open texture with some limited evidence of boiling textures. This part of the vein
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