OceanaGold Waihi North Project Vibration Performance Assessment Page 8 of 41 Project Number: HP2006-2 Heilig & Partners Save Date: 21/06/2022 5:55:00 PM ABN 56 082 976 714 File Name: WAI-985-000-REP-LC-0018_Rev 0 properties along Clarke and Moore Streets and Boyd Road. The potentially affected areas are similar to those areas where perceptible vibration was generated by the Favona underground mining area. Perceptible vibration from the mining of the GOP will be largely confined to the eastern side of State Highway 25 and not including any properties in the Waihi CBD area. Notwithstanding these comments, compliance with a set of vibration criteria that maintains amenity and eliminates damage to buildings is necessary. WUG is well removed from sensitive properties with the closest receivers all further than 5 kilometres and located along Maratoto Road (towards the west), Golden Cross Road (towards the south), or State Highway 25 (towards the east). To the north, there are no properties within 10 kilometres of the mine. There is no requirement to introduce an amenity-based vibration criteria given the large separation distances to sensitive receivers. The Willows Access tunnel is similarly positioned with respect to sensitive receivers. Given the separation distances, there will be no vibration impact on sensitive receivers from any blasting. Because the decline will be developed prior to other activities, there is a lesser requirement to impose a requirement to comply with vibration criteria as there are no existing properties near to the planned alignment. For completeness, it is prudent however to adopt the same proposed blast vibration criteria limits proposed for the GOP for the initial length of the access decline from the portal to the northern boundary of the Willows Road property. For the dual decline north of the Willows Road farm out to the orebody, no vibration criteria are proposed. The section of development is well removed from residential areas, and vibration at the surface above the development face will be minor and short-lived, reducing any potential for vibration effects on other possible sensitive receivers, e.g. Archey’s frog. The WUG Access Tunnel to processing plant runs along the north-east area of Waihi, crossing Golden Valley, Mataura, Oldfield and Wharry Roads. In some areas of the tunnel alignment, the tunnel passes near to, or beneath existing properties. Vibration criteria to maintain amenity, which also eliminates any chance of property damage, will be appropriate governance over the scale of blasting that can be undertaken. Whilst the proximity of blasting for WNP to potentially sensitive receivers vary according to whether the blasting occurs in WUG, GOP or either of the two tunnel accesses, a set of vibration criteria that maintains amenity and protects against building damage is proposed. 6. BLASTING VIBRATION LIMITS Ground vibration limits are typically set to preserve personal amenity, which are at levels below those at which property damage could occur. There is no one limit in use worldwide, but rather limits vary with countries like New Zealand and Australia adopting the most stringent values applied anywhere in the world. Vibration limits are always based on research conducted over decades by various independent groups, and subsequently form the basis for internationally accepted standards and guidelines. By design, they are typically conservative to provide a high safety factor, particularly with reference to building damage. In some cases, vibration limits may be expressed as a single value, for example 5 mm/s, where the focus is the protection of amenity. Where the focus is for the protection of structure response, such as the criterion given in British and German Standards, it is more likely that the applicable value will vary based on frequency. Vibration levels for the protection of amenity vary, but typically the most stringent of these levels is around 5mm/s. Where vibration may occur throughout the day, night time periods are always less than the applicable daytime value, sometimes around ½ the daytime value. However, it is more common that any vibration during the night is limited to a level that is imperceptible, or just above the level of perception.
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