Waihi North Project Terrestrial Ecology Values and Effects of the WUG Prepared for OceanaGold (NZ) Ltd WAI-985-000-REP-LC-0007. Rev 0 22 June 2022 This document has been produced for New Zealand consenting purposes only. Information contained herein must not be relied on for investment purposes.
Boffa Miskell is proudly a Toitū carbonzero® consultancy Document Quality Assurance Bibliographic reference for citation: Boffa Miskell Limited 2022. Waihi North Project: Terrestrial Ecology Values and Effects of the WUG. Report prepared by Boffa Miskell Limited for OceanaGold (NZ) Ltd. Prepared by: Katherine Muchna Senior Ecologist - Principal Boffa Miskell Limited Reviewed by: Sarah Flynn Senior Ecologist - Principal Boffa Miskell Limited Status: Final draft Revision / version: 0 Issue date: 22 June 2022 Use and Reliance This report has been prepared by Boffa Miskell Limited on the specific instructions of our Client. It is solely for our Client’s use for the purpose for which it is intended in accordance with the agreed scope of work. Boffa Miskell does not accept any liability or responsibility in relation to the use of this report contrary to the above, or to any person other than the Client. Any use or reliance by a third party is at that party's own risk. Where information has been supplied by the Client or obtained from other external sources, it has been assumed that it is accurate, without independent verification, unless otherwise indicated. No liability or responsibility is accepted by Boffa Miskell Limited for any errors or omissions to the extent that they arise from inaccurate information provided by the Client or any external source. Template revision: 20210624 0000 File ref: WAI-985-000-LC-0007 Cover photograph: Willows Road Farm, 2021
WAI-985-000-LC-0007 Executive Summary The Waihi North Project comprises several components to expand the Waihi operation including a new open pit (Gladstone Open Pit) and one new underground mine, Wharekirauponga (WUG). This report provides an ecological assessment of the terrestrial components associated with the (WUG) only. The Project Site for the WUG includes two discrete areas, Willows Road Farm where the portal and supporting surface infrastructure will be located, and Coromandel Forest Park where ventilation raises will be located. Willows Road Farm The primary effect associated with Willows Road Farm activities is the loss of low value vegetation (2,500 m2) and potential fauna habitats that vegetation provides within the project footprint. As part of the integrated mitigation package, OGNZL propose to revegetate approximately 56,600 m2 of the available riparian areas for ecological and landscape mitigation purposes. The remaining effects (construction noise and discharges to air) will be minimised through engineering design and site management processes. The level of effects with mitigation and management measures on Willows Road Farm range from Low to Very Low. Coromandel Forest Park The primary effect of the Project within Coromandel Forest Park is the temporary loss of vegetation / habitat (0.0576 ha) at the four ventilation raise sites and associated change in vegetation community when these sites are restored (at the close of mining). These effects will be offset by replanting and facilitating the natural regeneration of an approximately 4.15 ha area on the north east ridge of Willows Road Farm to connect Coromandel Forest Park with a forest fragment on Willows Road Farm. Additional ecological benefits associated with this project include replanting the forest boundary on Willows Road Farm (5.5 ha). Additional potential ecological effects associated with WUG include disturbance to fauna from construction and helicopter noise; continuous noise emissions from the vent raises; increased predator activity around camps and vent raise sites during construction; and the potential to introduce kauri dieback disease into the forest environment during works. Activities around vent raise sites occupy a very small area within the context of the forest and we consider that these effects can be minimised to a low level of effect using a combination of avoidance measures (i.e. locating vent raise sites in areas not occupied by native fauna); engineering and design solutions (i.e. construction of the vent raise from the underground rather than from the surface, vent raise design to maximise emission dispersion, and location of the fan at the base of the raise to reduce noise); site management and timing (i.e. avoiding vent raise construction during nesting or active periods for fauna, minimising helicopter activity and using a small helicopter model); and using established hygiene and biosecurity control practices (i.e. local predator control around camp and construction sites, and testing, cleaning and surveillance practices to prevent kauri dieback introduction and spread). There is a low (but uncertain) risk for this project to generate residual adverse effects on Archey’s and Hochstetter’s frogs from water and air discharges from the vent raises and the surface expression of blast vibrations. The primary offset / compensation measure to
address these potential residual effects is wide scale intensive pest control over an area of 633 ha including 314 ha exposed to vibration levels greater than 2mm/s and 318 ha immediately adjacent. Compensation as research funding is proposed to undertake investigative work within the WUG and wider Wharekirauponga Animal Pest Management Area to assess efficacy of pest control regimes for frog recovery. Additional research into the distribution and habitat use of Archey’s frogs within the Coromandel Peninsula is an ongoing research area. Within the wider WNP we have adopted an integrated effects management strategy that means in most cases the ecological mitigation and the landscape mitigation planting take a similar form and in the same key locations, or links locations to one another. Ecology is integrated with landscape to provide a more continuous connection of vegetation and freshwater environments, which will benefit biodiversity throughout the proposed project footprint whilst also providing benefit from a landscape and visual perspective. Where there were opportunities to provide additional ecological benefit, outside of the need for mitigation / offset, these are noted. In line with the intention of OGNZL, we have sought a net gain in biodiversity and ecological value in applying the effects management hierarchy and a demonstration of enhanced connectivity is part of this net gain. In our assessment, the effects of the Project on terrestrial ecological values are minimised to the extent possible through design and management processes; and offset / compensated where appropriate.
WAI-985-000-LC-0007 CONTENTS Executive Summary i 1.0 Introduction 1 1.1 Background 1 1.2 Approach 1 1.3 Report Structure 2 2.0 WNP Project Location and Description 2 2.1 Project Location 2 2.2 WNP Project Description 3 2.3 Wharekirauponga Project Activities 5 2.4 Ecological Context 10 3.0 Definitions, Assessment Criteria and Statutory Obligations 11 3.1 Introduction 11 3.2 Waikato Regional Council RPS 11 3.3 Hauraki District Plan 11 3.4 Wildlife Act and RMA Obligations with Respect to Fauna Protections 12 4.0 Description of Methods 12 4.1 Survey Constraints 12 4.2 Existing Wharekirauponga Ecological Data 13 4.3 Assessment and Survey of Vegetation 15 4.4 Assessment of Terrestrial Invertebrates 16 4.5 Assessment and Survey of Native Frogs 17 4.6 Assessment and Survey of Native Lizards 17 4.7 Assessment and Survey of Native Bats 18 4.8 Assessment and Survey of Avifauna 19 4.9 Assessment of Ecological Values 20 4.10 Evaluating the Level of Effect 20 5.0 Ecological Descriptions and Values 23 5.1 Vegetation Communities 23 5.2 Terrestrial Invertebrate Values 29 5.3 Ecological Values of Native Frogs 30 5.4 Ecological Values: Native Lizards 35
5.5 Native Bat Values 38 5.6 Native Bird Values 40 5.7 Indigenous Biodiversity Significance 44 5.8 Summary of Ecological Values 45 6.0 Actual and Potential Ecological Effects 46 6.1 Proposed Works and Associated Effects 46 6.2 Review of Potential Fauna Responses to Non-Lethal Disturbance and Stressors 46 6.3 Willows Road Farm 49 6.4 Coromandel Forest Park: Potential Localised Effects 55 6.5 Coromandel Forest Park: Potential Long-term Effects 66 6.6 Level of Effects on Terrestrial Vegetation, Habitats and Species 72 7.0 Integrated Landscape and Ecological Response 76 8.0 Proposed Ecological Management 78 8.1 Summary of Effects Management Measures 78 8.2 Avoid 78 8.3 Remedy 79 8.4 Mitigate 79 8.5 Biodiversity Offsetting / Compensation 80 8.6 Additional Ecological Benefits 86 8.7 Summary of Effects Management 88 9.0 Summary and Conclusion 89 10.0 References 91 Appendices Appendix 1: Criteria for Determining Significance of Indigenous Biodiversity Appendix 2: Wharekirauponga Survey Effort and Summary of Findings Appendix 3: Vegetation Descriptions for Willows Road Farm and Potential Vent Raise Sites Appendix 4: Vibration Effects on Amphibians
WAI-985-000-LC-0007 Figures Figure 1: Location and layout of the WNP. .....................................................4 Figure 2: Willows Road Farm surface infrastructure.......................................7 Figure 3: Indicative shaft locations in Coromandel Forest Park. ....................9 Figure 4: Revegetation plantings around Waihi town. ..................................10 Figure 5: Baseline ecological survey study area, a 2 km2 area within the Wharekirauponga catchment. This figure indicates broad-scale vegetation mapping and RECCE survey locations (top); and fauna monitoring locations (bottom). ...........15 Figure 6: Riparian vegetation within the footprint of the proposed Willows Rock Stack at Willows Road Farm, Waihi. Downstream view (left), upstream view (right). ...........................24 Figure 7: Vegetation assessment areas at Willows Road Farm. ..................25 Figure 8: Potential vent raise sites surveyed in Wharekirauponga...............27 Figure 9: Lizard and frog records in Wharekirauponga catchment...............32 Figure 10: Noise and air quality contours at Willows Road Farm. ................53 Figure 12: Noise and air quality in Coromandel Forest Park. .......................62 Figure 12: Wharekirauponga vibration contours. ..........................................68 Figure 13: Integrated Mitigation Package for the Willows Road Farm site. ..............................................................................................77 Figure 15: Offset planting areas....................................................................82 Figure 16: Wharekirauponga Pest Management Area. ................................85
WAI-985-000-LC-0007 GLOSSARY The table below sets out the defined terms and acronyms used in this document. Term Meaning Alimak A proprietary mast climbing (rack and pinion) access system developed by Alimak Group AB (Sweden; https://alimak.com/new-equipment/) that has been adapted to facilitate bottom-up underground shaft construction Canopy Tallest layer of the forest CFP Coromandel Forest Park Collection Pond A pond for the purpose of gathering and retaining run-off water until it is in a state suitable for discharging to the surrounding environment. This may include settlement, treatment, and interception/removal of hydrocarbons Cryptic species Species camouflaged and adapted for concealment in their habitat Construction works Activities undertaken to construct the Project DOC NZ Department of Conservation Earthworks Excavation and/or placement of cleanfill to change the contour or level of a site or part of a site (HDC) Ecological District (ED) A particular geographical region that has a characteristic landscape and range of biological communities Edge effects Changes in population or community structure that occur at the boundary between two different habitats FAR Fresh air raise providing fresh air to the mine ventilation system GOP Gladstone Open Pit GOP TSF Gladstone Open Pit converted to a tailings storage facility following the end of mining HDC Hauraki District Council HDP Hauraki District Plan (2019) LENZ Land Environments of New Zealand
WAI-985-000-LC-0007 Term Meaning LINZ The Government Land Information Service of New Zealand LoM, LoMP Life of Mine Plan, Plan for the Life of the Mine Mitigation package A collective term used in this report that includes all aspects of the ‘mitigation hierarchy’ MUG OGNZL’s existing Martha Underground Mine NAF Non-Acid Forming: Rock that does not contain elements which may oxidise (weather) to form water soluble compounds capable of forming an acid NRS Northern Rock Stack OBDA Overburden Disposal Area OGNZL Oceana Gold (New Zealand) Limited PAF Potentially Acid Forming: Rock that contains elements which may oxidise (weather) to form water soluble compounds capable of forming an acid. Plant Access Tunnel A decline connecting the OGNZL Waihi processing plant area with the dual tunnels commencing at ventilation shaft 1 on Willows Farm largely for the transportation of ore and rock to and from the WUG mine. Paper road HDC legal road reserve: a legally-recognised road that is undeveloped or partly formed, but provides public access to a particular area or feature. The paper road for the WNP refers to a corridor that ranges in size from approximately 15 m – 150 m wide within Coromandel Forest Park that is owned by the local authority (HDC). PAMP Pest Animal Management Plan Processing Plant The plant and associated infrastructure required to extract the gold and silver from the ore Project area The area within the proposed project footprint, and immediate surrounds to the extent Project works extend beyond this footprint. RAR Return air raise exhausting ventilation air from the mine.
WAI-985-000-LC-0007 Term Meaning RECCE RECCE plot methodology is the collection of vegetation data within a 20 x 20 m plot (Hurst & Allen, 2007). RPS Regional Policy Statement WUG SFA Surface Facilities Area located on farmland at the end of Willows Road to service the new Wharekirauponga Underground Mine Significant Natural Area (SNA) Areas of significant terrestrial indigenous vegetation or significant habitats of indigenous fauna located either on land or in freshwater environments identified in District Plans. SNAs are assessed using the criteria for determining significant indigenous vegetation and significant habitats of indigenous fauna contained in the Waikato Regional Policy Statement, and nationally recognised criteria. The sites are identified on the planning maps and are listed in the schedule at the end of Section 6.2 as Significant Natural Areas. Site A habitat assemblage within the Project area identified and assessed by the Project team. Terrestrial Land-based (i.e. terrestrial vegetation, terrestrial fauna). Torpor Decreased physiological activity in an animal, usually by a reduced body temperature and metabolic rate. Vent Raise 1 A ventilation shaft located on the Willows Road Farm. Located close to Department of Conservation land on the western boundary of the property. Vent Raises 2-5 Ventilation shafts located on Hauraki District Council owned, gazetted “paper” roads within the Department of Conservation controlled Coromandel Forest Park. WAA Wildlife Act Authority Willows Access Tunnel A decline connecting the WUG Surface Facilities Area with the dual tunnels commencing at Vent Raise 1. Willows Portal The access portal to the decline tunnel from the WUG surface facilities, located at the end of Willows Road, Waihi. Willows Road Farm A farm property of 197 hectares located at the end of Willows Road, Waihi, on which surface infrastructure and a
WAI-985-000-LC-0007 Term Meaning portal will be constructed in support of the Wharekirauponga Underground mine, WRC Waikato Regional Council WRC RPS Waikato Regional Council Regional Policy Statement WNP Waihi North Project WTP Water Treatment Plant WUG Wharekirauponga Underground Mine component of the WNP WUG Portal The portal to the ore handling tunnel from the OGNZL Waihi Processing Plant area to the bottom of Vent Raise 1 for connection to the dual tunnels to the orebody
Boffa Miskell Ltd | Waihi North Project | Terrestrial Ecology Values and Effects of the WUG | 22 June 2022 1 1.0 Introduction 1.1 Background The current Waihi life of mine plan (LoMP), including Project Martha, is to complete production by the end of 2030. Study work conducted between 2016 and 2020 identified opportunities to expand the Waihi operation with one new open pit, Gladstone Open Pit (GOP), and one new underground development (Wharekirauponga). OceanaGold New Zealand Limited (OGNZL) has engaged Boffa Miskell Limited (BML) to prepare an Assessment of Ecological Effects for the Wharekirauponga elements of the proposed Waihi North Project (WNP, the Project). This report is the first of two volumes, provided to inform the preparation of the Assessment of Environmental Effects (AEE, Mitchell Daysh 2022), and further project details are contained therein. The Waihi North Project comprises several elements, including: • a new underground mine and associated facilities (Wharekirauponga Underground Mine or WUG); • a new open pit (Gladstone Open Pit, GOP); • a new tailings storage facility (TSF3); • a new rock stack (the Northern Rock Stack, NRS); • upgrades to the existing Waihi Processing Plant and Water Treatment Plant (WTP); and • reconsenting of the existing treated water discharge to the Ohinemuri River. BML has worked with OGNZL and the consultant team to avoid, where practicable, and minimise impacts on the ecological values throughout the project design. 1.2 Approach This report is the first of two volumes that comprise the Ecological Assessment of Effects. Volume 1 describes the terrestrial ecology assessment for the WUG component of the WNP, including site context; ecological survey and assessment methods; ecological values and significance assessment; ecological effects assessment and proposed impact management strategy to address those effects. Volume 2 describes the freshwater ecology assessment of the WNP (BML, 2022a). A third report details effects on the terrestrial ecological values of the other components of the Project (Bioresearches, 2022). Our approach utilises the Environment Institute of Australia and New Zealand (EIANZ) impact assessment guidelines (Roper-Lindsay et al., 2018) approach to assess ecological values and significance, and the magnitude of the project’s adverse effects on the site’s ecological values. Criteria for assessing significance also included those contained the Waikato Regional Policy Statement (RPS) (WRC, 2016). Jointly, our reports describe the assessment of the environmental effects of the project on any: • Terrestrial, wetland and freshwater ecological values of the Wharekirauponga underground mine and associated facilities; and
2 Boffa Miskell Ltd | Waihi North Project | Terrestrial Ecology Values and Effects of the WUG | 22 June 2022 • The wetland and freshwater ecological values of the GOP; and • The wetland and freshwater ecological values of TSF3; and • The wetland and freshwater ecological values of the NRS; and • The wetland and freshwater ecological values of the Processing Plant and WTP upgrade. We present each of these components within separate chapters associated with the main project activities. As discussed above, terrestrial ecological values and effects assessment for the GOP, TSF3, NRS, and Processing Plant are provided in Bioresearches (2022). The WNP takes an overall ‘Nature Positive’ approach to impact management whereby all potential impacts on biodiversity are mitigated / compensated / offset (as appropriate) to a level that a Net Gain is the expected outcome. 1.3 Report Structure This report is set out as follows: Section 1 presents an overview of the project and our assessment approach. Section 2 describes the project location, detailed project description and site context. Section 3 provides an overview of relevant statutory matters. Section 4 describes ecological survey and assessment methods, including effects assessment methodology. Section 5 describes the ecological values of the Project Site and surrounding area and their significance with reference to the RPS. Section 6 describes and evaluates potential ecological effects. Section 7 outlines proposed ecological management. Section 8 provides a summary and conclusion. 2.0 WNP Project Location and Description 2.1 Project Location The OceanaGold’s Waihi operations are located within the Waihi township, near the east coast of the North Island of New Zealand. The site currently consists of the Martha Open Pit and the Correnso, Slevin, Favona, Trio and Martha Underground mines. The site is predominantly located within a primarily rural area in the Hauraki District, with access from State Highway 25 (SH25). The proposed footprint of the surface works for the Waihi North Project is set across five areas of works as listed in section 1.2 above (Figure 1). The land surrounding the current mining operations (mainly zoned Martha Mineral Zone) is predominantly rural, with the exception of the Martha Pit which is surrounded by residential, low-
Boffa Miskell Ltd | Waihi North Project | Terrestrial Ecology Values and Effects of the WUG | 22 June 2022 3 density residential and town centre areas. Those proposed surface works not located within the existing Martha Mineral Zone are largely located within the Rural Zone (refer the Hauraki District Plan). The WUG is located under the Coromandel Forest Park (CFP) (administered by the Department of Conservation, DOC), within the Mataura, Ramarama, Waiharakeke and Wharekirauponga catchments. The WUG is located south of Otahu Ecological area, the only Ecological Area in the Waihi Ecological District. The portal entrance, Surface Facilities Area, services corridor, and the tunnel to processing plant at Willows Road are located in predominantly rural land north of Waihi township. 2.2 WNP Project Description The WNP provides for two mining operations, sufficient surplus rock storage and tailings disposal areas and sets appropriate closure criteria. Establishment of a new Surface Facilities Area near the Willows Road portal will be required to support the tunnelling and subsequent mining at Wharekirauponga. A new portal for ore delivery and rock return will be constructed close to the Processing Plant for servicing the Wharekirauponga mine via a tunnel extension to meet at the Willows Road vent raise 1 (underground). Details of the Project are provided in the Assessment of Environmental Effects (Mitchell Daysh 2022). As set out above, the Waihi North Project comprises several components (Figure 1): • A new underground mine, Wharekirauponga, located approximately 11km north-west of the current Processing Plant under DOC-managed land (Coromandel Forest Park). Site infrastructure supporting the mine will be located on OGNZL owned farmland located at the end of Willows Road (Figure 2). The underground mine would exhibit only minimal surface features, in the form of fenced vent raises, on legal road owned by Hauraki District Council; or other suitable sites (Figure 3); • The mining of a new open pit near the existing Processing Plant, centred over Gladstone Hill, the Gladstone Open Pit (GOP). This pit will be converted to a tailings storage facility on completion of mining; • A new tailings storage facility to the east of existing TSF1A, called TSF3; and • New rock stack (NRS) at the Northern Stockpile area adjacent to the existing TSF2. • Changes to the layout of the existing Processing Plant to enable ore processing up to 2.25 million tonnes per annum (MTPA), up from 1.25 MTPA currently.
WAIHI NORTH PROJECT Site Context Date: 22 June 2022 | Revision: 1 Plan prepared for Oceana Gold by Boffa Miskell Limited Project Manager: [email protected] | Drawn: BMc | Checked: KMu www.boffamiskell.co.nz Fi le Ref: BM210482_ECO_01_A3L_SiteContext.mxd 0 2 km 1:70,000 @ A3 Projection: NZGD 2000 New Zealand Transverse Mercator Data Sources: Proposed Infrastructure sourced from Oceana Gold Public Conservation land sourced from DOC Topo map sourced from LINZ Topo 50 map series This plan has been prepared by Boffa Miskell Limited on the specific instructions of our Client. It is solely for our Client's use in accordance with the agreed scope of work. Any use or reliance by a third party is at that party's own risk. Where information has been supplied by the Client or obtained from other external sources, it has been assumed that it is accurate. No liability or responsibility is accepted by Boffa Miskell Limited for any errors or omissions to the extent that they arise from inaccurate information provided by the Client or any external source. Tunnel Portal Vent raises 2-5 located in this zone Proposed Tunnel Envelope (Underground) Services trench Project Area Proposed Fill Proposed Pit Public Conservation Land Paper Road Wharekirauponga Walk LEGEND Figure 1 Shaft 1 Shafts 2-5
Boffa Miskell Ltd | Waihi North Project | Terrestrial Ecology Values and Effects of the WUG | 22 June 2022 5 2.3 Wharekirauponga Project Activities The WUG Project Area has two components: the portal entrance and associated surface infrastructure located on the OGNZL landholding currently in use as a farm (Willows Road Farm); and up to four discrete sites within the Wharekirauponga Stream catchment within CFP where the vent raises and egress shaft will be located. Willows Road Farm to WUG Portal Background The Willows Road Farm comprises 197 ha of primarily pastoral land located approximately 5 kilometres north of the Waihi township. The Project Area is accessed from SH25 at the foothills of the Coromandel Ranges. Surface infrastructure will include workshops, administrative buildings and materials / chemicals storage areas, private roads, a helipad, an explosives magazine, sumps / ponds for general surface water and mine water collection, carparking, a tunnel portal and ventilation raise, a rock storage pad (approximately 5 ha), topsoil stockpiles (2 – 3 ha) and holding ponds1 (Figure 2). The surface infrastructure footprint comprises approximately 18 ha of farmland (approximately 9.1 % of total). Once mining is complete, all surface infrastructure will be removed, and footprint areas will be rehabilitated with stored topsoil. The land will be returned to arable farming land. Rock Stack The design of the rock stack incorporates dish drains around the stockpile which separate catchment water from rock stack contact water. Springs within the catchment of Tributary 2 will be capped and the water piped beneath the rock stack and delivered to Tributary 1 below the rock stack. . Catchment water will be directed back to the Mataura Stream. During the mining operation all rock stored on the rock stack will be returned underground as backfill. Once this occurs, the overburden will be removed and Tributary 2 will be rehabilitated and returned largely to its original configuration, with improved riparian areas and stock exclusion fencing to protect the waterway. Services Trench A buried Services Trench connecting the Willows Road Farm to the existing Processing Plant will carry electricity, fibre optic cables and treated / potable and recycled water. A materials handling portal will be located near the Processing Plant in Waihi (the WUG Portal) which will be used to transport ore out of the mine and rock back to the mine for stope backfilling. Services Trench construction will be standard cut and cover trenching by a small excavator. Some drilling may be required beneath SH25 but it is that this can be completed through standard trenching methods. Tunnel development The method of tunnel development for the Willows Access Tunnel, the Dual Access Tunnel and the Wharekirauponga Access Tunnel is by drill and blast, which has practical advantages for the project. The impacts of drilling and blasting and their associated dust, noise and vibrations for the Dual Access Tunnel and Willows Access Tunnel are assessed in this report. Tunnelling speed will be approximately 10 meters per day. The Wharekirauponga Access Tunnel is a single decline tunnel that connects Willows Road Farm to the Processing Plant in Waihi and is not discussed here. 1 The pads will be lined with a low-permeable base and include provision for drainage and collection of runoff water into sediment (or collection) ponds. The holding ponds for each rock stack will have a capacity of approximately 9000m³, designed to contain a 1 in 100 storm event and include a sump and pumping station. Contact water collected in the pond will be pumped to the existing Waihi Processing Plant for treatment and disposal.
6 Boffa Miskell Ltd | Waihi North Project | Terrestrial Ecology Values and Effects of the WUG | 22 June 2022 Wastewater Human wastewater from the operations at Willows Farm will be treated on site by a package sewage treatment plant (STP). Discharge water from the STP will be directed into a seepage field on the site. The seepage field will be located remotely from the Mataura Stream and its tributaries.
! !( #* #* Tr G i G ib uu uu l t l a y ry Feeature WMWMa e t t a la u n r d a d a Tributary 3 Tributary 1 Tributary 2 Tr GG ib u u l t l a y a y rryy Feeatuure MatauraStream Mataura Stream Mataura Stream Mataura Stream Mataura Stream WAIHI NORTH PROJECT Proposed Willows Road Site Layout Date: 07 April 2022 | Revision: 1 Plan prepared for Oceana Gold by Boffa Miskell Limited Project Manager: [email protected] | Drawn: BMc | Checked: KMu www.boffamiskell.co.nz Fi le Ref: BM210482_ECO_02_A3L_WKP_SiteLayout.mxd 0 200 m 1:5,000 @A3 Projection: NZGD 2000 New Zealand Transverse Mercator Data Sources: Waterways and Roads sourced from LNZ data service Proposed Infrastructure sourced from Oceana Gold ° This plan has been prepared by Boffa Miskell Limited on the specific instructions of our Client. It is solely for our Client's use in accordance with the agreed scope of work. Any use or reliance by a third party is at that party's own risk. Where information has been supplied by the Client or obtained from other external sources, it has been assumed that it is accurate. No liability or responsibility is accepted by Boffa Miskell Limited for any errors or omissions to the extent that they arise from inaccurate information provided by the Client or any external source. !( Tunnel Portal ! Indicative Shaft #* Freshwater Sampling Site Wetland Willows Road Site Cadastre Project Area Access Road\Path Building Footprint Parking Bund Hard landscape Magazine Footprint Retention/Collection Ponds Willows Rock Stack Topsoil Stockpile Earthworks LEGEND Figure 2
8 Boffa Miskell Ltd | Waihi North Project | Terrestrial Ecology Values and Effects of the WUG | 22 June 2022 Coromandel Forest Park Background Coromandel Forest Park (CFP) is administered by DOC and adjoins the north western boundary of the Willows Road Farm. The primary project elements associated with the CFP land will be located underground and comprise a dual decline tunnel, mine excavations and stopes underground drill platforms. Above ground elements within the road reserve (paper road) or conservation estate include up to four vent raises. The existing helicopter pads, accommodation hut and a pump site will continue to be used to service the drilling and mining operation. Vent Raises Vent raises will be constructed from the bottom up using the Alimak method (i.e. constructed from within the tunnel). This method minimises footprint size and level of disturbance on the surface (within CFP). Geotechnical considerations may require additional reinforcement of the vent raise collar, but the surface footprint will be limited to 12 x 12 m. Vent raises will be constructed at different stages of the mine life in response to resource extensions and mining schedules, and vent raises may be converted between intake and return (or vice-versa). Once operating, steam plumes may be visible from return air raise (RAR) discharges under certain climatic conditions (typically during winter and in periods of higher relative humidity). Once mining is complete surface infrastructure will be removed and vent raise areas will rehabilitated. Water Management Incidental, minor quantities of water emanating from the ground and/or from normal tunnelling operations will be drained to sumps within the tunnel. Suitable water will be diverted for recycling underground for mine equipment and surface dust suppression. The balance of water will be pumped to the Waihi processing plant for treatment and discharge. Where significant quantities of water are encountered in tunnelling, the ground in the immediate vicinity will be shotcreted and/or grouted to provide an effective seal to prevent any significant and/or sustained drainage of local groundwater. Current hydrogeological data from the tunnel route is limited, however geology of the area is well understood. It is predicted that the dewatering volume will increase incrementally as the tunnel is developed until completion. Prior to commencement of the first stoping operation, drilling and grouting will be undertaken if required in the upper development drives to ensure no water is lost from surface water bodies when mine dewatering commences. Current data, modelling and expert analysis indicates that the surface water is in contact with the vein system but only at shallow depths and not highly interconnected. Hence such grouting is expected to be highly effective in preventing surface water loss through mining and dewatering. Where necessary, grouting will continue well ahead of mining throughout the mine life. Mining at shallower depths will be or limited and monitored to ensure no risk of surface water drainage. Ongoing work is underway to understand the groundwater system to design appropriate measures to avoid effects on surface water bodies.
!( !( Waihi Whangamata Rd Waihi Whangamata Rd GoldenCross Rd Willows Rd Corbett Rd 25 25 Waitek auri River Wa l msley St ream Waiharak eke Stream Whakamoehau Stream Walmsley Stream Whirit oa Stream Mataora Stream Ohinemuri R iver Kathleen Stream Teawaotemutu St ream Cascade Stream Mataura Stream GraceDarling Stream Edmonds Stream Thompson Stream Stony Stream Maratoto Stream Ratarua S tream Waipaheke Stream Junction Stream Ramarama Stream Wai h arakekeStream Ri gh t Branch BarneysStream WAIHI NORTH PROJECT Indicative Wharekirauponga Vent Raise Locations Date: 21 February 2022 | Revision: 1 Plan prepared for Oceana Gold by Boffa Miskell Limited Project Manager: [email protected] | Drawn: BMc | Checked: KMu www.boffamiskell.co.nz Fi le Ref: BM210482_ECO_03_A3L_ShaftSiteLocations.mxd 0 800 m 1:30,000 @A3 Projection: NZGD 2000 New Zealand Transverse Mercator Data Sources: Waterways and Roads sourced from LNZ data service Proposed Infrastructure sourced from Oceana Gold LIDAR sourced from WRC ° This plan has been prepared by Boffa Miskell Limited on the specific instructions of our Client. It is solely for our Client's use in accordance with the agreed scope of work. Any use or reliance by a third party is at that party's own risk. Where information has been supplied by the Client or obtained from other external sources, it has been assumed that it is accurate. No liability or responsibility is accepted by Boffa Miskell Limited for any errors or omissions to the extent that they arise from inaccurate information provided by the Client or any external source. !( Tunnel Portal Willows Rock Stack Willows Road Site Project Area Proposed Tunnel Envelope (Underground) Wharekirauponga Walk Vent raises 2-5 located in this zone Road Parcels Cadastre LEGEND Figure 3
10 Boffa Miskell Ltd | Waihi North Project | Terrestrial Ecology Values and Effects of the WUG | 22 June 2022 2.4 Ecological Context The WNP Project Area is located within the Waihi Ecological District (Waihi ED) which includes the land from Whangamata south to Waihi Beach and encompasses the entire project area. With the exception of CFP land, much of the vegetation in Waihi ED has been modified through farming and urban development. Native forest within Waihi ED comprises tawa-dominated forest with emergent northern rata, rimu, totara, miro, pukatea and kauri (Kessels & Associates, 2010). The Waihi ED includes the southern extent of Coromandel Forest Park and all of Wharekirauponga area (located above WUG). The land surrounding the existing mine operations, excluding the Martha Pit, is generally open with predominantly grazed pasture with some areas of plantation pine, native vegetation and low-density rural dwellings. The land is typically low-lying with some rolling hills and small ridges. Considerable planting has been undertaken across the Waihi site and surrounding areas by OGNZL (and the former Waihi Gold), with 455,400 plants planted between 1995-2016 (Figure 4). Of these plants 206,541 were identified as ‘riparian’ plantings and a further 14,379 and 41,805 plants were identified as ‘swamp’ and ‘gully’ plantings respectively. These plantings totalled 35.31 ha of restoration plantings in and around Waihi . The location of these plantings includes TB1 Stream and a number of associated wetlands, Eastern Stream, and the lower reaches of the Ruahorehore Stream and tributaries (Figure 4). These plantings have improved the ecological value and function of these watercourses and wetlands. We emphasise that these enhancements have been entirely voluntary by OGNZL and have not been undertaken as part of any regulatory or land purchase requirements. Figure 4: Revegetation plantings around Waihi town.
Boffa Miskell Ltd | Waihi North Project | Terrestrial Ecology Values and Effects of the WUG | 22 June 2022 11 3.0 Definitions, Assessment Criteria and Statutory Obligations 3.1 Introduction In this section we comment on the relevant statutory definitions to be applied to ecological features of the WNP and appraise the criteria to be applied in assessing significant indigenous vegetation and/or habitats of indigenous fauna. We emphasise that this section is not a statutory assessment. In this section we make reference to: • WRC RPS • HDC Plan • Wildlife Act (1953) and RMA obligations 3.2 Waikato Regional Council RPS The Waikato Regional Council (WRC) RPS sets out the criteria for identifying areas of significant indigenous biodiversity and their characteristics as they exist at the time the criteria are being applied (WRC 2016). Criteria may be specific to a habitat type including water, land or airspace or be more inclusive to address connectivity, or movement of species across habitat types. The criteria are provided in Appendix 1. The significance of ecological habitat within the proposed project footprint was evaluated using the ‘Criteria for determining significance of indigenous biodiversity’ in Section 11A of the RPS. This criteria states that “To be identified as significant an area needs to meet one or more of the criteria identified in the table below” (i.e. in Table 11-1 of the RPS (Appendix 1)). Vegetation, habitats and ecosystems within CFP (above the WUG) meet multiple criteria for determining significance (described in Section 5.7). Terrestrial biodiversity values in the WUG works footprint outside of CFP (i.e. Willows Road Farm) do not meet RPS significance criteria. 3.3 Hauraki District Plan The WUG is located below predominantly rimu-tawa forest in CFP. This land is also classified as SNA T13 P152 (HDP 2019), a large SNA which adjoins the property at Willows Road. Point 7(h) in Section 6.2.1 of the District Plan also states that if an area of indigenous habitat that is not listed as an SNA due to a lower ecological ranking, it can still be environmentally important and therefore adverse effects on it should be avoided, remedied or mitigated as appropriate.
12 Boffa Miskell Ltd | Waihi North Project | Terrestrial Ecology Values and Effects of the WUG | 22 June 2022 3.4 Wildlife Act and RMA Obligations with Respect to Fauna Protections Native animals including bats, birds, lizards, frogs and some invertebrate species are ‘absolutely protected’ under the Wildlife Act (1953, s63 (1) (c)), and their habitats are protected by the Resource Management Act (1991) and administered by the DOC and local authorities (WRC and Hauraki District Council, HDC), respectively. A Wildlife Act Authority (WAA permit) is required to handle, catch, release or kill native wildlife including lizards, birds, bats and frogs. Granting a WAA is at the discretion of the Department of Conservation and typically requires that conditions2 are met to ensure the safety of wildlife. These conditions may include limiting who may undertake the activity (e.g. experienced persons only), a maximum number of animals that can disturbed and the timing and quantity of surveys. A WAA will be sought for the WUG to allow for the survey and handling of native frogs and lizards within CFP vent raise sites. A separate WAA will be sought for the survey and handling of native lizards at Willows Road Farm and other WNP project areas. 4.0 Description of Methods 4.1 Survey Constraints Seasonal and weather constraints to animal activity (i.e. animals not able to be detected) prevented a comprehensive ecological survey (including native frogs, native lizards and native orchids in particular) of all of the potential vent raise sites from being undertaken for this assessment. Existing information about Wharekirauponga is described in Section 4.2. Full ecological surveys (as outlined below) will be undertaken in all areas where vegetation and habitat clearance is required as these are confirmed (including vent raise sites in CFP, and in the footprint of Willows Rock Stack at Willows Road Farm). Cryptic and rare species have poor survey detection rates and multiple surveys in suitable conditions are required to increase detectability3. We note that poor detectability is an inherent characteristic of many of these 2 Wildlife Act Authorisations are a separate process to resource consent and DOC may impose conditions to the authority in addition to those included in a resource consent. 3 Taxa specific constraints to fauna surveys include: Lizards: Lizard survey methods currently available have poor detection rates as a consequence of typically low population densities, species’ cryptic colouration, difficulty in surveying preferred habitats and behaviour/activity patterns. As such, even an intensive lizard survey will not detect all individuals in the population or, possibly all species present. Lizard survey methods are strongly weather dependent, and surveys will be carried out in fine weather when lizards are most likely to be active. The specific limitations associated with survey methods (as described in Department of Conservation Inventory and Monitoring Toolbox: Herpetofauna (Hare 2012; Lettink and Monks 2016)) are understood by the author. Frogs: Frog survey methods have many of the same limitations as lizard survey methods. Observer experience and undertaking surveys over multiple nights’ of suitable weather is very important in assessing frog presence. A description of specific limitations associated with survey methods (as described in Department of Conservation Inventory and Monitoring Toolbox: Herpetofauna (Hare 2012) are understood by the author. Bats: Bat activity is closely correlated with temperature and weather (O’Donnell, 2002) and multiple nights’ of survey are required to have confidence in bat use of an area. Identifying roost trees is difficult without knowing if the site is within a bat colony’s home range. The baseline survey is intended to assess whether the proposed vent raise sites form part of a short-tailed or long-tailed bat colony’s home range and, if so, contains roost trees. A description of the limitations associated with bat surveys is provided in (Sedgeley, n.d.).
Boffa Miskell Ltd | Waihi North Project | Terrestrial Ecology Values and Effects of the WUG | 22 June 2022 13 species (as evidenced by generally poor records) and the known range of many of these species has not been thoroughly surveyed. Whilst the presence of some invertebrate species may indicate intact forest ecosystems, there are no well-established indices that signify terrestrial macroinvertebrate species or community values or their sensitivity to disturbance. Robust macroinvertebrate community data is timeconsuming and difficult to collect and meaningfully analyse, and a particular consideration for this site is that sampling methods may endanger other forest species (i.e. risk of native frogs or lizards falling into pitfall traps). DOC has provided a list of invertebrate taxa that may act as ‘general indicators of forest health4’, and we comment on observations of these in the absence of more specific data where relevant. Where site-specific ecological data was unavailable (i.e. for cryptic fauna or flora), we draw on records from surveys undertaken within the wider Wharekirauponga catchment (Section 4.2). Whilst the paper road area was not sampled specifically in those surveys, the ecological communities have very similar characteristics, allowing inferences to be drawn where data is unavailable. Further, final vent raise sites have not yet been confirmed and the full range of fauna and vegetation surveys have not been completed. We propose that these surveys are carried out as part of the site selection process (Section 6.4.2) to ensure impacts on fauna and mature vegetation are avoided. Consent to clear and undertake exploration drilling on two of the four proposed vent raise sites may be sought through a separate consent process, but will be subject to the same survey / site selection requirements. 4.2 Existing Wharekirauponga Ecological Data Existing ecological data for the Wharekirauponga area includes survey data collected during ecological surveys to locate potential new exploration drill sites / camp sites / pump sites (undertaken between 2017 – 2021, BML 2018, 2019a, 2021a), and broad-scale baseline ecological surveys carried out in 2019 and 2020 (BML 2019b, BML 2022b (in preparation)). A summary of survey effort and findings of these surveys is provided in Appendix 2. Broadly, repeated ecological surveys of terrestrial and aquatic communities have been undertaken within an approximately 2 km2 area in the Wharekirauponga catchment (Figure 5)5. The purpose of the surveys was to provide a broad-scale biodiversity inventory for the area to document species presence, distribution, and rarity / commonness. The surveys were carried out using standardised, replicable methods that provide baseline ecological data for pre-selected sites. These methods allow for the inventory to be repeated over time to assess change to the vegetation, some fauna species, and freshwater ecological communities in this area. Surveys were designed to enable integration with existing data where possible. Specific assessments of the following habitats, communities and populations included: 4 https://www.doc.govt.nz/get-involved/run-a-project/restoration-advice/bush-restoration/understand-the-bush/whyinvertebrates/ 5 The vegetation and fauna surveys were undertaken within an area of approximately 2 km2 that included the catchments of Adams Stream, Thompsons Stream, Teawaotemutu Stream, Edmonds Stream and the upper reaches of Wharekirauponga Stream. Freshwater surveys were undertaken at two sites on the Teawaotemutu Stream and two sites on the Wharekirauponga Stream, downstream of the public walking track.
14 Boffa Miskell Ltd | Waihi North Project | Terrestrial Ecology Values and Effects of the WUG | 22 June 2022 • Vegetation surveys (RECCE plots and incidental observations of ‘Threatened’ and ‘At Risk’ species, and orchids, transect vegetation surveys) • Bird surveys • Lizard surveys • Archey’s and Hochstetter’s frog surveys • Bat surveys • Paua slug surveys The study area for these surveys encompasses the proposed vent raise sites within the paper road at the end of tunnel area; and includes all active exploration drill sites for which data is referenced throughout this report (Figure 5).
Boffa Miskell Ltd | Waihi North Project | Terrestrial Ecology Values and Effects of the WUG | 22 June 2022 15 Figure 5: Baseline ecological survey study area, a 2 km2 area within the Wharekirauponga catchment. This figure indicates broad-scale vegetation mapping and RECCE survey locations (top); and fauna monitoring locations (bottom). 4.3 Assessment and Survey of Vegetation 4.3.1 Desktop Analysis Desktop review of available literature on vegetation to inform this assessment included aerial imagery; the SNA report (Waihi ED, (Kessels & Associates, 2010)), Land Environments New Zealand (LENZ) Threatened Environment Classification maps and botanical lists (where available); and collation of existing catchment-specific information from previous surveys (BML 2019, 2022b (in preparation)). 4.3.2 Vegetation Surveys Vegetation surveys comprised site walkovers and rapid plant community assessments at Willows Road Farm. The farm property was assessed over a total of 5 days in July and November 2020, January 2021 and November 2021. Stands of vegetation were typically fragmented and smaller than the 20 x 20 m minimum size requirement for a RECCE plot. A site walkover was carried out in the proposed services trench footprint to assess ecological values on 11 November 2021. Vegetation and habitats on the boundary of Coromandel Forest Park were assessed in May 2022. RECCE plot surveys were carried out at 14 potential vent sites within the paper road in CFP from March 2021 to May 2021. The purpose of sampling 20 x 20 m RECCE plots was to identify
16 Boffa Miskell Ltd | Waihi North Project | Terrestrial Ecology Values and Effects of the WUG | 22 June 2022 in more detail habitat and plant communities present within potential vent raise sites, including species composition, species diversity and vegetation structure. Final vent raise locations are not confirmed, but detailed vegetation assessments at potential vent raise sites within the paper road provide a robust description of the vegetation communities and enables evaluation of the ecological quality of each of the potential sites. Vegetation descriptions completed to date are provided in Appendix 3, and further surveys are proposed in 2022 - 2023. RECCE plot methodology is the collection of vegetation data within a 20 x 20 m plot. Within each plot, the cover-abundance of all species present is assessed in six standard height tiers (>25 m tall, 12-25 m, 5-12 m, 2-5 m, 30 cm-2 m, <30 cm). Six cover-abundance classes are used (< 1%, 1– 5%, 6–25%, 26–50%, 51–75%, 76–100%). A detailed description of the method is provided in Hurst & Allen (2007). We note that, due to the recent incursion of myrtle rust (Austropuccinia psidii) into New Zealand, all Myrtaceae species which were previously been classified as ‘Not Threatened’ have been elevated to ‘Threatened - Nationally Vulnerable’ or ‘At Risk – Declining’. Myrtle rust is a fungal disease that severely attacks plants in the myrtle family which includes mānuka, kānuka and rātā. Most new classifications of Myrtaceae as Nationally Vulnerable are a precautionary measure due to the unknown impact of myrtle rust on native species. DOC (2018a) notes that the classifications for mānuka, kānuka and common Metrosideros species are Designated (i.e. these abundant and widespread species do not meet standard threat status criteria). Kauri (Agathus australis) has also been recently classified as ‘Threatened- Nationally Vulnerable’ due to the increased spread of kauri dieback (Phytophthora agathidicida, PA) by human and pig (Sus scrofa) movements (Krull et al., 2013). Kauri and Myrtaceae species are commonly encountered throughout the Coromandel Ranges, hence we did not document individual observations of these taxa, but rather looked for evidence of disease when these species were encountered. While we have not documented numbers of kauri observed during surveys in this document, we note that OGNZL has an existing kauri dieback monitoring programme in Wharekiraupongaa that includes mapping and health assessment of kauri. 4.4 Assessment of Terrestrial Invertebrates 4.4.1 Desktop Analysis The desktop assessment for terrestrial macroinvertebrates included a literature review including iNaturalist records from the Coromandel area, and data contained in the Coromandel-Thames SNA report (Waihi ED, (Kessels & Associates, 2010)). Incidental records of conspicuous terrestrial macroinvertebrates, including peripatus / Ngaokeoke (Peripatoides spp), wētā and paua slug (Schizoglossa worthyae), collected during surveys in the Wharekirauponga catchment were reviewed (BML 2018, 2019a, 2019b, 2021). 4.4.2 Surveys No targeted terrestrial macroinvertebrate surveys were carried out as part of this assessment, either on Willows Road Farm, the services trench or within CFP. The invertebrate values assessment for the vent raise areas in CFP, and the CFP on the edge of Willows Road Farm was based on observations of conspicuous invertebrate species recorded during fauna surveys.
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