This document may not be reproduced in full or in part without the written consent of Marshall Day Acoustics Limited Rp 001 R0 20210601 SJP (Waihi North Noise Assessment) ISSUE 24 of 79 5.1.3 Modelling Parameters Our modelling is based on the following physical parameters: Table 8: Summary of significant modelling parameters Variable Input Terrain elevation Wide terrain from LINZ 8m DEM6 Base elevation surrounding site from LiDAR scans provided by OGNZL Annual contours for each pit/raise provided by Engineering Geology Ltd Ground absorption Generally defined as ‘mixed’ (G = 0.5) Hard (G = 0.0) areas defined for: • All OGNZL worksite areas, stockpiles etc. • Waihi township urban area • Water areas such as TSF ponds Source positions All heights of equipment in Table 9 relative to local terrain elevation. Receiver positions All receiver dwellings assumed to be single storey. Calculated at the rural notional boundary line or urban property boundary, at 1.5 metres above ground General barriers and obstacles Majority of buildings modelled at 5m height (based on LINZ NZ Building Outlines) No fences, bunds, etc. accounted for outside of OGNZL properties Spatial definition All points referenced to LINZ cadastral boundaries (NZ Primary Parcels) Vegetation attenuation No losses assumed from any plantings or vegetation. For terrain data, OGNZL also provided working elevation contours for each of the four areas, which broadly all involve creating either pits or embankments/stockpiles. These data have been combined with terrain information noted above. The input data (in terms of noise sources) used for the GOP, NRS and TSF3 components of the project is similar, given that they all generally make use of standard earthmoving and mining plant. The assumptions on these are given below in Table 9. 6 NZ 8m Digital Elevation Model (2012), National Topographic Office (from LINZ) Noise data for the WUG, Processing Plant and other minor elements is more specific to those project components. The input data for these are discussed later in the respective sections of this report. Table 9: Operational noise source data for GOP, TSF3 and NRS models Plant/Equipment Level, dB LwA Height, m Operating Time*, % GOP TSF NRS Cat 16G 32t Grader 110 3.0 54 41 25 Cat 20t Excavator 103 2.0 - - 50 Cat 50t Excavator 109 2.5 81 67 25 Cat 777 165t Dump Truck 115 3.5 81 - - Cat 785 140t Haul Truck 114 4.0 - 67 75 Cat 825 35t Compactor 110 3.5 - 67 20 Cat 992 100t Loader 116 4.0 - 58 - Cat 988 51t Loader 110 3.0 81 - - Cat D10 70t Dozer 115 4.0 54 58 50 Drilling Rig 115 4.0 81 - - Hitachi 180t Excavator 120 4.0 81 - - Komatsu D65 23t Dozer 106 2.5 - 67 50 Underground Truck 114 2.0 100 - - Volvo 20t Dump Truck 110 3.0 81 67 75 Water Cart 117 3.0 38 41 25 GOP RoM Crusher 119 4.0 100 - - * Operating time is the percentage of daytime shift that plant is in use for. 5.2 Construction Noise The activities considered as construction noise were identified in Section 4.1. Broadly, this includes the following types of sources: • Earth moving machinery to prepare land, remove overburden and construct noise control bunds, etc. • Excavation of tunnel portals using mining techniques such as drilling and blasting. • Civil engineering plant for internal road and haul route construction, plus realignment and installation of services in the public road corridor. • Standard construction plant such as cranes and telehandlers to establish site infrastructure and surface facilities. • Surface connection of the WUG ventilation raise sites. Examples of typical construction equipment noise source levels used in our assessment are given below in Table 10. Table 10: Indicative noise levels for typical construction equipment Noise Source Noise Level, dB LwA Height, m Road planer 110 3.0 Vibratory plate 108 1.0 Hand-held circular saw 107 1.0 Water tanker vacuum pump 107 2.0 Dumper 107 3.0 Vibratory compactor on excavator 106 1.5 Tracked excavator 103 1.5 Asphalt paver & tipper 103 2.0 Vibratory roller 103 1.5 Mini excavator 102 1.0 Compressor 93 1.0 Water pump 93 0.5 Dumper (idling) 91 3.0 Calculations of construction noise were in line with the general environmental noise modelling described above. The main difference in assessment methods is that the construction noise Standard (NZS 6803:1999) applies to noise levels received at the façade of occupied buildings, whereas the general District Plan noise standards apply at either the site or notional boundary. Most of the activities listed will occur on OGNZL property and generally at the primary worksites. We understand that the main construction works occurring outside of OGNZL land or works areas will be associated with WUG and Willows Road to construct the services trench to the Waihi Processing Plant (via SH25) and Willows Road and likely intersection upgrades required for traffic engineering purposes. For any construction work, noise levels will typically vary significantly over the course of the project, depending on the nature and location of activities. As such, we have primarily focused more on the calculation of minimum setback distances, rather than the investigation of noise levels at specific receivers. The setback distances from construction activities indicate the typical area beyond which compliance can be achieved with the construction noise limits. Where receivers fall within a noncompliant area, the distance-based approach can help manage
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