OceanaGold Waihi North Project Vibration Performance Assessment Page 23 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 proposed as a method of minimising vibration related impacts on the surface, and possible disturbance to the Archey’s Frog population. The preliminary assessment modelling has considered four mining scenarios. The blast designs range from the smaller cut and fill options with 6 kilograms per blasthole that may be used for the upper section of the mine through to the larger 76mm, single column with 59 kilograms per blasthole for the deeper sections. The concept for the design is to maintain a level of vibration at the surface which is consistent with the recommendations of the herpetologists and that which was modelled from the mining of the Golden Cross orebody. The blast design options will vary according to the vibration limits. Figure 8 – Preliminary blast designs options for WUG based upon minimising potential vibration impacts to the Archeys Frog population Blast Design Description Explosive Weight per deck A Single column 51mm diameter blasthole, 4m blasthole length with a 0.6m uncharged collar. Explosive density consistent with 0.9g/cm3. 6 kilograms B Two 6m decks into 64mm diameter blasthole, 15m blasthole length with a 2m uncharged collar. Explosive density consistent with low density emulsion at 1g/cm3 19 kilograms C Single column 64mm diameter blasthole, 15m blasthole length with a 2m uncharged collar. Explosive density consistent with 1g/cm3. 43 kilograms D Single column 76mm diameter blasthole, 15m blasthole length with a 2m uncharged collar. Explosive density consistent with1g/cm3. 59 kilograms Table 6 – Preliminary blasting options for WUG Single column 64mm diameter blasthole, 15m blasthole length with a 2m uncharged collar. Explosive density consistent with1g/cm3. Two 6m decks into 64mm diameter blasthole, 15m blasthole length with a 2m uncharged collar. Explosive density consistent with low density emulsion at 1g/cm3 Low Density Emulsion 19kg per deck Low Density Emulsion 59kg per hole 2m uncharged collar Single column 76mm diameter blasthole, 15m blasthole length with a 2m uncharged collar. Explosive density consistent with1g/cm3. DESIGN A Single column 51mm diameter blasthole, 4m blasthole length with a 0.6m uncharged collar. Explosive density consistent with 0.9g/cm3. DESIGN C DESIGN D Low Density Emulsion 19kg per deck DESIGN B Low Density Emulsion 43kg per hole Low Density Emulsion 6kg per hole
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