Supporting Technical Assessments

EGL Ref: 9018 22 June 2022 Page 25 WAI-985-000-REP-LC-0006_Rev0.docx This report shall only be read in its entirety. During site establishment and, uphill diversion drain construction, TB1 stream diversion, foundation works and establishment of infrastructure and collection pond, only NAF material will be cut or placed and therefore erosion and sediment controls can follow typical erosion and sediment control practices as outlined by Waikato Regional Council Guidelines for Soil Disturbing Activities (Ref. 12). Use of flocculant may be required to meet these guidelines. Flocculant use is currently prohibited by the existing resource consent conditions that authorise other structures but may be necessary during the initial construction phase of NRS and needs to be provided for. Once the site is controlled with a perimeter drain and collection pond and with pumped connection back to the Water Treatment Plant, use of flocculant will not be required. PAF material can be placed once the perimeter controls, subsurface drainage, Zone A pad, and return pumping system are in place. 14.0 OPERATION MAINTENANCE AND SURVEILLANCE OGNZL will have an Operation Management Plan (OMP) that will outline operational, maintenance and surveillance items for the NRS, similar to the Operational Maintenance and Surveillance (OMS) manual required for the TSFs. This OMP will include quality assurance during construction, the classification of the PAF/NAF material, maintenance of surface water and subsurface drains, surveillance of ground water and surface water quality, monitoring of surfaces for acid generally and application of limestone to surfaces, and regular review of stability assessments and controls. Surveillance and monitoring is to be undertaken to monitor the performance of NRS. The purpose is to allow the performance of the NRS to be assessed and reported, and provide for the detection and mitigation of potential deficiencies or adverse trends. This is important for geotechnical stability and ground water quality protection. Instrumentation that is likely required for monitoring the performance are summarised below: i. Piezometers are to be located in the stockpile and foundations and read monthly. ii. Deformation monitoring stations are to be installed at the toe of the NRS embankment and on rehabilitated benches, and surveyed yearly. iii. Seepage flows and groundwater sampling in the subsurface and leachate drains to be measured monthly. iv. Visual inspection of the stockpile to be undertaken monthly. v. Slurry testing of the surface material for pH and lime dosing to occur monthly. vi. Visual inspection of the NRS Collection Pond to occur weekly or during rainfall. vii. Visual inspection of the uphill and perimeter drain to occur weekly or during rainfall. 15.0 CONSENTING REQUIREMENTS Consent requirements relate to the obligations under the Resource Management Act (1991) and the Building Act (2004). The Resource Management Act relates to the use of resources (air, water, land) and discharges to the environment and requires an assessment of effects. The Building Act relates to the structures and their performance requirements, which are set out in the Building Code under the Building Regulations (1992). The likely consenting requirements are set out for the relevant parts of the NRS in the following sections.

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