2018 TECHNICAL REPORT ON THE PEBBLE PROJECT, SOUTHWEST ALASKA, USA NORTHERN DYNASTY MINERALS LTD. Effective Date – December 22, 2017 Issue date February 22, 2018 Qualified Persons J. David Gaunt, PGeo. James Lang, PGeo. Eric Titley, PGeo. Ting Lu, PEng. Stephen Hodgson, PEng. T A B L E O F C ONTENTS 1.0 Summary ......................................................................................................................................... 1 Introduction ................................................................................................................................................... 1 Project Location ............................................................................................................................................ 2 Property Description ................................................................................................................................. 3 Geological Setting and Mineralization ........................................................................................................ 4 Mineral Resource .......................................................................................................................................... 5 Mineral Processing and Metallurgical Testing ........................................................................................... 7 Environmental, Permitting and Social Conditions ..................................................................................... 8 Project Description ........................................................................................................................................ 9 Interpretation and Conclusions.................................................................................................................. 10 Recommendations ....................................................................................................................................... 10 1.10.1 Recommended Program .................................................................................................................. 10 1.10.2 Additional Recommendations ......................................................................................................... 11 2.0 Introduction .................................................................................................................................. 12 Terms of Reference and Purpose ............................................................................................................... 12 Sources of Information and Data ............................................................................................................... 13 Qualified Persons ......................................................................................................................................... 13 3.0 Reliance on Other Experts .......................................................................................................... 14 4.0 Property Description and Location ............................................................................................ 15 Location ........................................................................................................................................................ 15 Description ................................................................................................................................................... 16 Surface Rights .............................................................................................................................................. 26 Environmental Liabilities ........................................................................................................................... 26 Permits ......................................................................................................................................................... 26 5.0 Accessibility, Climate, Local Resources, Infrastructure and Physiography Accessibility .... 27 Access ........................................................................................................................................................... 27 Climate ......................................................................................................................................................... 28 Infrastructure .............................................................................................................................................. 28 Local Resources ........................................................................................................................................... 29 Physiography ............................................................................................................................................... 29 6.0 History ........................................................................................................................................... 30 Northern Dynasty Minerals Ltd. 2018 Technical Report on the Pebble Project, Southwest Alaska - i- Introduction ................................................................................................................................................. 30 Historical Sample Preparation and Analysis ............................................................................................ 32 6.2.1 Sample Preparation ......................................................................................................................... 32 6.2.2 Sample Analysis .............................................................................................................................. 33 Historical Resource Estimates .................................................................................................................... 33 Ownership History ...................................................................................................................................... 34 7.0 Geological Setting and Mineralization ....................................................................................... 37 Regional Geology ......................................................................................................................................... 37 Property Geology ......................................................................................................................................... 38 7.2.1 Kahiltna Flysch ............................................................................................................................... 38 7.2.2 Diorite and Granodiorite Sills ......................................................................................................... 38 7.2.3 Alkalic Intrusions and Associated Breccias .................................................................................... 40 7.2.4 Hornblende Granodiorite Porphyry Intrusions ................................................................................ 40 7.2.5 Volcanic-Sedimentary cover sequence ........................................................................................... 40 7.2.6 Hornblende Monzonite Porphyry Intrusions ................................................................................... 41 7.2.7 Eocene Volcanic Rocks and Intrusions ........................................................................................... 41 7.2.8 Glacial Sediments ........................................................................................................................... 41 7.2.9 District Structure ............................................................................................................................. 41 Deposit Geology ........................................................................................................................................... 43 7.3.1 Rock Types ..................................................................................................................................... 43 7.3.2 Structure .......................................................................................................................................... 43 Deposit Alteration Styles ............................................................................................................................. 50 7.4.1 Pre-hydrothermal Hornfels.............................................................................................................. 50 7.4.2 Hydrothermal Alteration ................................................................................................................. 50 7.4.2.1. Early Potassic and Sodic-Potassic Alteration ................................................................. 50 7.4.2.2. Intermediate Illite ± Kaolinite Alteration........................................................................ 53 7.4.2.3. Late Advanced Argillic Alteration.................................................................................. 53 7.4.2.4. Propylitic Alteration ....................................................................................................... 54 7.4.2.5. Quartz-Sericite-Pyrite and Quartz-Illite-Pyrite Alteration .............................................. 54 7.4.3 Post-Hydrothermal Alteration ......................................................................................................... 55 Deposit Mineralization Styles ..................................................................................................................... 55 7.5.1 Supergene