Waihi North Project Preliminary Site Investigation (Ground Contamination) Williamson Water & Land Advisory Limited 32 Land use Potential contaminants Possible extent of contamination HAIL Assessment Areas potentially impacted Asbestos use in buildings (historic) HAIL Activity E1: Asbestos in a degraded condition Asbestos No asbestos was observed on current buildings and given their age of construction (1990s onwards) asbestos use is unlikely. Historic buildings that may have contained asbestos have been long demolished and the ground beneath heavily modified such that there is no potential for contamination to remain. HAIL Activity E1 does not apply to the site. - Mining HAIL Activity E7: Mining industries Wide ranging, refer to all other activities. Activity E7 is a ‘catch all’ for a range of mining activities, many of which are categorised elsewhere in this table with more specificity. Potential for contamination is limited to areas of workshops, dangerous goods storage, and water treatment, with other parts of site largely just used for ancillary activities, offices, etc. HAIL Activity E7 applies to the site. All processing plant areas. Workshops HAIL Activity F4: Engineering workshops Metals, hydrocarbons A range of workshops are located around site including electrical, engineering and vehicle workshops. We have used this HAIL Activity to represent all workshops. Most have concrete floors and therefore negligible potential for contamination. However, some workshops have gravel floors meaning there is a high potential for shallow soil contamination within their footprint. Associated areas of waste oil storage may also have localised contamination if not paved or contained. HAIL Activity F4 applies to the site. Workshops only. Water treatment plant HAIL Activity G6: Wastewater treatment Wide ranging reflecting the range of chemicals used on site. While much of the water collection system and ponds are lined, some are not and there is potential for sediment within unlined areas of the water treatment system to have accumulated a range of chemicals, particularly from spill events when the rate of discharge to the treatment system may not have been able to be controlled. Given the volume of water that moves through the system and therefore the degree of flushing, overall potential for contamination is relatively low, but cannot be ruled out. HAIL Activity G6 applies to the site. WTP Chemical and fuel spills HAIL Activity I: Accidental release of a contaminant in sufficient quantity to present a risk to human health or the environment Wide ranging but largely hydrocarbons and metals. While there have been a number of spills over the history of the Processing Plant’s operation, there are very few that have the potential to have resulted in contamination at levels that are likely to be high enough to present a risk to human health or the environment. While some surface contamination may have resulted from spills, it is sediment within the various ponds and the WTP that are most likely to have been impacted as these will be accumulation points for contaminants. HAIL Activity I likely applies to the site. WTP, cyanide mixing area.
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