Memorandum 1 Memorandum : Vibration effects on amphibians (Leiopelmatid frogs) 64524 Vibration effects_memorandum (15 June 2022)_Final Rev 0.docx To: OceanaGold (New Zealand) Limited Date: 15 June 2022 Attn: Stephanie Hayton Job #: 64524 Subject: Vibration effects on amphibians (Leiopelmatid frogs) 1.1 Introduction This memorandum has been prepared to assist with the effects management, specifically the effects of vibration, in relation to Leiopelmatid frogs (Archey’s frog, Leiopelma archeyi and Hochstetter’s frog, L. hochstetteri) at the proposed Wharekirauponga Underground Mine (WUG) (here after “the Project”). The document provides a summary of the biology and ecology of Archey’s and Hochstetter’s frog, a review of the available literature on vibration perception and effects on animals (including frogs), and an assessment of potential effects of mine blast vibrations on Leiopelma frogs. The Project requires the construction of a 6.8 km access tunnel system, commencing at a farm property owned by OceanaGold and extending beneath Department of Conservation (DOC) land (Coromandel Forest Park (CFP)) to the Wharekirauponga resource, to undertake further exploration and subsequent mining. The Project will comprise tunnel portals, a tunnelling system, and only minimal surface features in the form of fenced vent raises on legal paper road owned by Hauraki District Council. Areas of surface disturbance will be sites that have been subject to ecological surveys and found to have very low (less than detectable) Archey’s frog abundance (Boffa Miskell, 2022). Areas of surface disturbance would not affect Hochstetter’s frog or their stream habitats. The chosen method of tunnel development is drill and blast, and noise and vibration associated with these activities are expected both during the drilling phase at ventilation sites and operationally during firing (blasting) to form the underground tunnel. Refer to section 4.5.1 Tunnelling Cycle of the Waihi North Project: Project Description (Document No.: WAI-985-000-SOW-GE-0001) for details in the development mining cycle, including anticipated firing (blasting) frequency and duration. Many animals are sensitive to substrate-borne vibrations and vibration detection is an important sense that is used for intra- and interspecific interactions in diverse animal taxa (Takanashi et al., 2016). While there is a growing body of evidence that suggests that anthropogenic substrate vibrations (cf. anthropogenic noise) could be sources of mechanical disturbance for animals, the field remains largely under researched and the effects on numerous groups of animals are poorly understood. The blasting required to shatter rock in the proposed WUG will result in seismic vibrations (vibrations transmitted through the substrate) that will propagate to the ground surface where Leiopelma frogs are known to occur. It is unclear if or how these surface vibrations would affect the resident frog populations in terms of behaviour or persistence over time. Here we attempt to understand these potential effects by examining the ecology of Archey’s and Hochstetter’s frog and seeking examples from the available literature of vibration effects on other species.
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