Supporting Technical Assessments

Waihi North Project Preliminary Site Investigation (Ground Contamination) Williamson Water & Land Advisory Limited 38 3.5 Proposed Tailings Storage Facility 3 Site description summary The site is an operating dairy farm with two dairy sheds, two dwellings and a series of hay and implement sheds, largely clustered around the southeast boundary of the site. Proposed developments The land will be significantly reworked to create a new bund that rises 46 m above the existing ground level (at the downgradient end). TSF3 will have capacity for 5.7 Mm3 of tailings. Water and leachate collection drains, and other associated facilities will also be required in this area. Site history summary The site has been used for dairying/ livestock grazing for much of its history, with localised market gardening occurring in the central east in the 1980s and 1990s. Some dwellings and sheds date from times when Asbestos-Containing Material (ACM ) use was common although no ACM was observed on the farm buildings, but the dwellings will more likely than not contain ACM. We have considered all potential contaminating (HAIL) activities for the future TSF3 site in Table 7 below, with Figure 15 illustrating their spatial distribution. Table 7. Potential for contamination: TSF3 Land use Potential contaminants Possible extent of contamination HAIL Assessment Areas potentially impacted Drench use in yards and storage in sheds HAIL Activity A8: Livestock dip or sprayrace operations Arsenic, organochlorines It is likely that pour-on drenches have been used in cattle yards. No livestock dips were noted. Given the more modern use, contamination is unlikely and if present, confined to surface soils in the immediate vicinity of the yards. HAIL Activity A8 applies to site. Yards adjacent to cow sheds, implement shed where drench is stored. Market gardening HAIL Activity A10: Persistent pesticide use Copper, organochlorine pesticides. Market gardening activities were relatively short-lived and post-date use of arsenic and lead, although there may have been some limited use of organochlorines as these were often still in use after they were banned in the 1970s/ 1980s. Any contamination is likely to be limited to surface soils and localised. HAIL Activity A10 applies to site. Two areas of market gardening in the centre and centre-east of the site. Diesel storage HAIL Activity A17: Storage tanks or drums for fuel Hydrocarbons, lead Two ASTs were observed, within each dairy shed complex. In our experience there is typically low to moderate levels of contamination beneath farm ASTs, but typically isolated to surface soils immediately beneath the ASTs. HAIL Activity A17 applies to the site. Immediately beneath ASTs. Asbestos use in buildings HAIL Activity E1: Asbestos in a degraded condition Asbestos There is potential for asbestos to be present on the two dwellings and possibly ancillary buildings (garages and garden sheds). If contamination is present, it is likely confined to surface soils immediately surrounding the dwellings. HAIL Activity E1 applies to the site. Immediately surrounding buildings.

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