Supporting Technical Assessments

6 Tonkin & Taylor Ltd Hazardous Substances Technical Assessment – Waihi North Project - Storage and use of hazardous substances at Willows Road site and the Wharekirauponga Underground Mine Oceana Gold (New Zealand) Limited June 2022 Job No: 1015212.1000 vRev0 Table 2.1: Hazardous substance volumes and classifications Substance State of substance HSNO Class Pre-2021 Hazard classification Post 2021 Proposed maximum volume Storage Location ANFO (UN 0082) Solid 1.1D, 6.1D, 6.3B, 6.7B, 9.1D 1.1D - Substances and articles that have a mass explosion hazard Acute toxicity Category 4 (oral route) Eye irritation Category 2 Carcinogenicity Category 2 Hazardous to the aquatic environment chronic Category 4 7,350 kg NEQ 6,100 kg NEQ Surface explosive magazines (max 1,300 kg NEQ in any magazine) Underground chambers (max 1,000 kg NEQ in any chamber) Booster (UN 0042) Solid in card or plastic casing 1.1D, 6.1C, 6.9B, 9.1B 1.1D - Substances and articles that have a mass explosion hazard Acute toxicity Category 3 (oral, dermal and inhalation route) Specific target organ toxicity – single exposure Category 2 Hazardous to the aquatic environment chronic Category 2 Packaged explosive (UN 0241) Plastic encapsulated emulsion 1.1D, 6.1D, 6.3A, 6.4A, 6.8C, 6.9A, 9.1A, 9.3C 1.1D - Substances and articles that have a mass explosion hazard Acute toxicity Category 4 (oral route) Skin irritant Category 1 Eye irritation Category 2 Reproductive toxicant Category 3 Specific target organ toxicity – repeated exposure Category 1 Hazardous to the aquatic environment Category 1 Harmful to terrestrial vertebrates Detonators (UN 0030 / UN 0456 / UN 0360) Solid article 1.1B 1.1B - Substances and articles that have a mass explosion hazard 10 kg NEQ (10,000 articles) Surface explosive magazine (separate to others) 100 kg NEQ (100,000 articles) Underground chamber (separate to others) Diesel Liquid 3.1D, 6.1E, 6.3B, 6.7B, 9.1B Flammable liquids Category 4, Aspiration hazard Category 1, See Note 1 Carcinogenicity Category 2, Hazardous to the aquatic environment chronic Category 2 80,000 L Services bay at the SFA 6,000 L WUG portable tanks 550 L Generator tank at the SFA 150 L Fire pump at the SFA

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