Waihi North Project Preliminary Site Investigation (Ground Contamination) Williamson Water & Land Advisory Limited 50 We consider that it is unlikely that the above permitted activity conditions can be met, as a Detailed Site Investigation will not be completed before consent is lodged. Controlled activity provisions (Rule 5.3.4.7) cannot be met for the same reason. Therefore, resource consent as a discretionary activity will be required under Rule 5.3.4.8 of the WRP. 5.4 Earthworks requirements While contamination is not expected to have any significant impact on the proposed works, there may be isolated areas where contaminated soils should be managed prior to bulk earthworks commencing. This is primarily with regard to ACM, as we expect most other potential contamination types can be managed by mixing (dilution) during bulk earthworks. Carrying out soil disturbance activities in general accordance with the SMP will ensure that human health is protected from the effects of soil borne contamination. The following management methods are outlined in the SMP, along with contingency measures to be implemented if unexpected contamination is identified or contaminants are discharged to the environment: Asbestos-in-soils Some asbestos is likely to be present in soils, although at low levels. This may trigger “Asbestos-Related” or in a worst-case scenario “Class B” works under the NZ Asbestos Regulations. Class B works would require engagement of a licensed asbestos removalist and may require them to prepare an Asbestos Removal and Control Plan (“ARCP”; similar to those included in the SMP). We recommend asbestos remediation is carried out before bulk earthworks so that asbestos controls can be removed for the remainder of works. Validation sampling is required after asbestos remediation to confirm asbestos impacted soils have been removed. Earthworks controls Other than for soils containing asbestos, standard earthworks controls and procedures would apply to the project, with additional focus on protecting worker health (i.e. good worker hygiene) and preventing discharges of sediment-laden water to the environment (watercourses) or stormwater system. Testing of runoff or dewatering water would be required if disposal to municipal stormwater or wastewater was proposed. Soil disposal We expect that with the exception of asbestos, all soils will be retained on site (either on the specific properties where they are sourced from or incorporated into rock stacks or tailings dams). Asbestoscontaminated soils, which are expected to be minor in volume, will likely require disposal to a licensed landfill facility that accepts asbestos waste. There is also the option to have a designated encapsulation area on site, but this may not be appealing to OGNZL in the long term (it would require ongoing management and monitoring and would likely have to be in an area that was not going to have future public access). Closure reporting If remedial actions occur, (i.e., building footprints where ACM is present or in the area of the diesel AST), validation sampling or visual inspection will be undertaken following remediation so contamination-specific controls can then be removed and bulk earthworks proceed under standard earthworks controls, and to address expected condition of consent (i.e., confirming the site status on completion of earthworks).
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