Supporting Technical Assessments

Waihi North Project Preliminary Site Investigation (Ground Contamination) Williamson Water & Land Advisory Limited 47 5. Development Implications 5.1 Overview The data presented in Sections 3 and 4 indicates there is potential for localised low to moderate levels of soil contamination to be present at all WNP sites, primarily as a result of mining processes and agricultural and horticultural activities. However, contamination is likely to be minimal in the context of the large-scale earthworks proposed in upgrade areas and will not present a significant risk to consenting and earthworks management. The following sections set out a suggested investigation scope along with development and consenting implications for the WNP. 5.2 Investigation requirements Localised pre-works investigations are recommended to enable any actual contamination in the identified HAIL areas (refer Figures 12 – 17) to be understood, and conversely eliminate uncontaminated areas. Contamination (if present) could impact on soil management and disposal costs (i.e. low level metal or hydrocarbon contamination could be retained on site within tailings dams, whereas asbestos would require disposal to a licensed landfill such as Tirohia). However, this PSI indicates that the volume of potentially contaminated soil across the project footprint is likely to be small, particularly in the context of the volumes of earthworks expected for the overall project. Pre-works sampling will also inform health and safety requirements for construction workers and site users, particularly around whether or not asbestos controls are required. Investigations will be targeted across the project area as in Table 12. Table 12. Investigation requirements. Area Proposed investigation Processing Plant and WTP site (existing) • Target shallow soil sampling only where soil disturbance is required to facilitate the WNP works. Testing based on the source of contamination immediately adjacent to investigation area. • Sediment sampling in unlined wastewater treatment ponds/ drains if subject to disturbance. Processing Plant and WTP site (expansion area) • Testing of old mine workings if they are proposed to be removed/ relocated (for metals, cyanide, hydrocarbons). GOP • Cattle yards are unlikely to be disturbed. Targeted sampling for arsenic and organochlorine pesticides within the cattle yards, only if disturbance is required. Existing TSFs No investigation required. TSF3 • Target testing for organochlorine pesticides and copper and/ or arsenic in market gardens and cattle yard areas as well as storage sheds. • Asbestos testing surrounding dwellings. • Hydrocarbon and lead testing of shallow soils immediately beneath fuel storage areas. NRS • Hydrocarbon and metal testing in the vicinity of the workshop, fuel storage and waste oil storage. • Asbestos testing around the dwelling. • Organochlorine and arsenic testing in shallow soils in cattle yards. Willows Road property and SFA Target testing only if soil disturbance is proposed in HAIL areas as follows: • Target testing for organochlorine pesticides arsenic in sheep/ cattle yard areas as well as storage sheds. • Asbestos testing surrounding dwelling and ancillary buildings and the dairy shed. • Targeted testing around the effluent sump for biological wastes. Coromandel Forest Park No investigation required

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