File: WAI-985-000-REP-LC-0050-Rev0.docx This report shall only be read in its entirety. CONTENTS Page No. EXECUTIVE SUMMARY III 1.0 INTRODUCTION 1 1.1. Waihi North Project 1 1.2. Project elements with potential ground settlement effects 2 1.3. Consented ground settlement effects 3 1.4. Dewatering and settlement monitoring plan and annual reporting 3 1.5. Assessment limitations and management of risks 3 2.0 GROUND SETTLEMENT OVERVIEW AT WAIHI 4 2.1. Ground settlement mechanism 4 2.2. Geology and hydrogeology interpretation 4 2.3. Historic mining operations 5 2.4. Modern mining operations 5 3.0 STUDY AREA GEOLOGY 6 3.1. Waihi to WUG geological setting 6 3.2. Geology Martha Open Pit to Favona Underground and Gladstone Hill 7 3.3. Gladstone Open Pit 8 3.4. Wharekirauponga Access Tunnel geology 9 3.5. Willows Road site geology 9 3.6. Wharekirauponga Dual Tunnel alignment 10 3.7. WUG Mine geology 10 4.0 WAIHI DEWATERING AND GROUNDWATER LEVELS 10 4.1. Historical Dewatering 10 4.2. Martha Open Pit, Favona, Trio and Correnso Underground Dewatering 1989-2021 11 4.3. Piezometer monitoring and interpretation 12 4.4. Martha Underground dewatering 13 4.5. Waihi North Project dewatering 14 4.5.1. Gladstone Open Pit 15 4.5.2. Wharekirauponga Access Tunnel 16 4.5.3. Willows Access Tunnel 16 4.5.4. Wharekirauponga Dual Tunnel 17 4.5.5. WUG – Mine drives, shafts and stopes 17 4.5.6. Ventilation shafts 18
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