OceanaGold Waihi North Project Vibration Performance Assessment Page 3 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 Figure 2 - Schematic of the final extents of the GOP In the initial year, the portal boxcut will be constructed. The new decline will be mined mainly from the Trio decline out to a new portal (Gladstone portal) where it will break through into the alreadyestablished box cut. GOP will be developed and mined over about six years at a maximum mining rate of around 3.5 million tonnes per annum (Mtpa) for a total mined quantity of 21.3Mt. The first stage of GOP involves mining to 1055RL. The second stage involves mining from Winner Hill and deepening of the eastern part of the pit to 1005mRL. GOP will operate 24 hours a day, 7 days a week and operations will include excavation, trucking of ore from the pit to the ROM stockpile, rock for underground backfill or to the existing Polishing Pond Stockpile (PPS) for temporary storage, or to the proposed Northern Rock Stack (NRS). Some operations may be restricted by night-time noise limits. Blasting is planned to occur only on dayshift at pre-set windows scheduled between 7am and 6pm, Monday to Saturday. In terms of scheduling, whilst mining of the GOP will occur contemporaneously with other OceanaGold works in Waihi, meaning that there will be an overlapping period of several years during which blasting occurs in both the GOP and the current Waihi operations, the distance between these areas will ensure no cumulative impacts. The distance between GOP and WUG means there are also no cumulative effects for receivers between the two new mining areas. 2.2. Willows Access Tunnel Access to WUG will involve driving 6.5 kilometre declines extending from the planned mine Surface Facilities Area at Willows Road through to the orebody. A single decline extends around 130 metres to the south-west before turning to north-west for approximately 1.5 kilometres (Willows Access Tunnel). At this point, the decline continues with dual tunnels linking to the mine (Dual Access Tunnels). The change in orientation near the portal helps to reduce overpressure from blasting in the initial section of the decline. The dual decline continues for another 5 kilometres in the same north-westerly direction to the upper levels of the underground orebodies. The decline dimensions are approximately 6 metres in height and 5.5 metres width with an arch profile.
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