Supporting Technical Assessments

7 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 Substance State of substance HSNO Class Pre-2021 Hazard classification Post 2021 Proposed maximum volume Storage Location Ammonium nitrate emulsion (ANE) Solid 5.1.1B 6.1E 6.4A 9.1D Oxidising solids Category 2 Aspiration hazard Category 1, Eye irritation Category 2 Hazardous to the aquatic environment chronic Category 4 40,800 kg Oxidiser intermediate bulk containers (IBC) storage area – SFA 34,000 kg Oxidiser IBC storage area – underground Gasser Liquid 6.1D 6.4A 6.5B 6.6B 6.9B Acute oral toxicity Category 4 Eye irritation Category 2 Skin sensitisation Category 1 Germ cell mutagenicity Category 2 Specific target organ toxicity – repeated exposure Category 2 8,000 L Gasser IBC storage area – SFA 4,000 L Gasser IBC storage area – underground Calcium carbonate (Lime) Solid 6.4A Eye irritation Category 2 70,000 kg Lime silo in SFA Oxygen gas Compressed gas 5.1.2A Oxidising gas Category 1 60 m3 Up to ten cylinders in a segregated storage area in the workshop in the SFA Acetylene gas Compressed gas 2.1.1A Flammable gas Category 1A, Chemically unstable gas Category A 20 m3 Up to four cylinders in a segregated storage area at the workshop in the SFA Oils, greases* Liquid 6.1D 6.1E 6.3A 6.4A 6.5B 6.9B 9.1B 9.1C Acute dermal toxicity Category 4 Aspiration hazard Category 1 Skin irritation Category 2 Serious eye damage Category 1 Skin sensitisation Category 1 Specific target organ toxicity – single or repeated exposure Category 2 Specific target organ toxicity – single exposure Category 3 narcotic effects Hazardous to the aquatic environment chronic Category 2 or 3 8,000 L Bulk tanks, IBCs or drums in workshop stores in SFA * Majority of the maintenance oils and greases are non-hazardous. The above table shows the highest individual hazard classifications for the range of workshop substances.

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