Structural Setting and Controls of Gold Mineraiization at the Macassa Mine, Kirkland Lake, On tario Alastair Charles Still A thesis submitted to the Department of Geological Sciences and Geological Engineering in conformity with the requirement of the degree of Master of Science Queen' s University Kingston, Ontario, Canada October, ZOO1 Copyright O Alastair C. Still, 2001 Biblioîhèuue nationale Acquisitions and Acquisions et Bibliographie ÇeMces se- bibliographique6 The author has granted a non- L'auteur a accordé une licence non exclusive licence aiiowing the exc1usive permettant a la National Li'brary of Canada to Bibliothèque nationale du Canada de reproduce, loan, disûiiute or sell reproduire, prêter* distniuer ou copies of this thesis in microfonn, vendre des copies de cette thèse sous paper or electronic formats. la fanne de microfiche/film, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor snbstantiai extracts fiom it Ni la thèse ni des extcaits substantiels may be printed or othemke de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. autorisation. Abstract The Macassa gold &mine is Located in northeastem Ontario, approximately 3 km West of the Town of Kirkland Lake. The mine produced more than 3.5 million ounces of gold between 1933 and 1999. Tbe Macassa mine was one of seven major gold mines in the Kicklaad Lake camp that collectively produced in excess of 74 million ounces of gold from an mastretching for approximately 7 km along strike, and to mining depths of 2-5 km. The Macassa goId mine is Iocated in the 2.75 to 2.67 biliion-yex-old Abitibi ,menstom belt. The mine is underlain by sedimentary and volcanic rocks of the Archaean Timiskaming Group in a package several kilometres thick that fl& and is sub-paralle1 to the rnost significant strucnire in the are& the Kiriciand Lake-Larder Lake break. Rocks of the Timiskaming Group unconformably overlie pre-Timiskaming volcanic rocks belonging to the Abitibi Supergroup, which include the Blake River Group votcmics, and the predorninantly thoteiitic Kinojevis Group. intruded into the Timiskaming sedimentary and voicmic rocks is a composite syenite stock with three main components consisting of augite syeniie, felsic syenite, and syenite porphyry. The intrusive rocks have hosted most of the ore at the Macrissa mine and throughout the Kirkland Lake gold camp. The Macassa mine is a stmcturally controlIed gold deposit. Structures conuolled intnision of the syenitic stocks, empIacement of the minedishg hydrothermal fluids. and post-on displacement. Most of the gold minerdization in Kirkiand Lake is associated with the Kirklmd Lake break (Main break) huit-system. and associaced sub-paralle! structures, The Main break is rnost Likely a Local branch or splay of the regionai KirkIand Lake-Larder Lake break. The sub-vertical, to steeply south-dipping, '04 break is the most important ore-related structure during the Iast two decrides of mining at the Macrissa Mine, The 'û4 break is located approxirnacely400 feet ( 121 rn) north of the North branch of the Main break. and is connected through a series of cross-over fauits that include the S and R breaks. Ore at Macassa consists of break-related ore. hmgingwall and footwall veins and breccia ore. Other sîgnificant ore-related structures at Macassa include the '05 break (referred to as the Nmows break in the eastern mines of Kirkiand Lake), and the 45-55" southdipping No. 6 break. Post-ore faulting at Macassa occurs along major faults that include the '04 North break, the Tegren fault, and the Amikougami Creek fault. Gold distribution in the Kirkland Lake gold camp demonstrates that the Lake Shore mine was situated near the cenm of the gold-bearing system. The gold-bearing ore of Kirkiand Lake has many characteristic components including the presence of telluride elernen ts (chiefly altaite, calmerite, and coloradoite), and the occunence of moiybdenite dong fine slips or minor faults on the margins of auriferous quartz veins- A sequence of geoIogical events for the formation of the Kirkland Lake ore has been proposed. The principal events indude: eariy volcanism; basin formation; intrusion of iilkaiine ïatrrisives; cooling of the inüusives; hydrothermai açtivity; minerakation; compressional defornation Iate in tfie ore-forming peria post-ore compressional deformation; and post-ore cross-faulting- Several exploration targets have been deveIoped for the Macassa mine. These includt: specific prospective areas dong the '04 break; mineraiised structures to the south of the '04 break, inciuding the No. 6 break, zones to the north of the '04 break, including the 'OS or Narrows break; and prospective hangingwall and footwd veins. There are many people to whom I owe my sincere gntitude and appreciation for rnaking this whole project possible, and for supporting me dong the long road towards completion. First and forernost 1mus& thank my wife, Lori, whose assistance with preparation of the manuscript and unwavering support from start to finish made the whole exercise possible. There have been many changes in our lives since the project started, and many obstacies that we have conquered. 1know that with your love, and now with the love of our daughter, Katherine, the whoie undertaking was possible and certainly worthwhiie. 1 aiso must thank my parents and my brother Cor their constant encouragement and support. 1 would like to thank Dr. Robert Mason and Dr. Herb Helmstaedt for their guidance and wisdom that belped mdce this undenaking come to fruition. Bob's eternai optimism and enthusiasm Iaunched me on this project, and Herb's patience, support, and inteIIectuai guidance ensured that the project couid be cornpleted. There are many inditiduals at Kinross Gold Corporation whom 1 must thank for providing the financial and inteHectual support necessary for tius project. Doug Cater had the visionary thinking and geologicai quest for knowledge necessary to initiate the project. and to ensure that 1 was able to continue working on it through some pretty rough times at Macassa I am indebted to Doug for his faith in rny abilities, and the opportunity to continue with my work. Tony Makuch provided the managerial support to initiate the project, and Steve Grinius was instrumental in supporting my resertrch and me so that the project could be completed. Gary Halverson, Boyd Timler, and Rod Cooper continued to support the project even after the Macassa mine was closed. Many of the geologists at Macassa provided insight and suggestions throughout the undertaking, so to ~MikeSutton. Andre Lauzon, Ken Rattee, Frank Ploeger, and Bob Levesque 1am sincerely thankful. Mike continues to be a wedth of information on the Kirkland Lake gold camp, and is a tnie geologicd prospector. Th& dso to my "buddy", lm Russell, for his support, fritndship, and the challenge CO see who could finish their thesis fmt. Table of Contents Abstract ii Acknowledgements iü Table of Contents iv List of Figures vü List of Tables ix Chapter 1: Introduction 1 Lucation 1 Purpose 1 Methodology 3 Previous Work 4 Chapter 2: Regional Geological Setting 6 Geology of the Abitibi Greenstone Belt 6 i) Introduction 6 ii) Suprcnistal Rocks 8 iii) Plutonic Rocks 10 iv) Strucninl Geology 10 V) Metarnorphism 10 vi) Formation of the Abitibi Belt i 1 Geology of the Kirkland Lake Camp 1 1 Kirkland Lake's "Mile of Gold" 18 Toburn 21 Sylvanite 23, Wright- Hargreaves 24 Lake Shore 28 Teck-Hughes 3 1 Kirkland take Gold 32 Macassa 34 Chapter 3: Macassa Mine Geology 35 introduction 35 Description of Host Rocks 36 A. Tiskarning Group 39 i) Congiomerate 39 ii) Greywacke 39 iii) Tuffs 4 1 iv) Tnchyte 41 B. Intrusive Rocks 41 i) Augite (Basic) Syenite 4 1 fi) FeIsic Syenite 42 iii) Syeaite Porphyry 42 C. Late Stase Dykes 43 Alteration 43 Mineraiization 44 Chapter 4: Structural Geology of Macassa 49 introduction 49 Major Mineralised Structures 49 '04 Break 49 Introduction 49 Mineraiization 52 Timing and Nature of Deformation 59 Main Break 59 Mineralised Stmctures 64 '05 Break 64 Mineralization 68 Deformation 70 No. 6 Break 75 Mineraiization 75 Timing Relationships 79 Related Significant Structures 8 1 North Break 8 1 Footwail Fault 82 South Break 83 Other Mineraiised Structures 84 North Porphyry Zone (NPZ) 84 Hangingwail Veins 86 introduction 86 Deformation 90 Footwail Veins 98 Post-Ore Faulting 99 '04 North Break 99 Timing Relationships 107 "Q Break 110 Tegren Fault 1 10 Amikougami Creek FauIt 1 12 Chapter 5: Gold Distribution in Kirkland Lake 116 Kickland Lake Gold Production 1 16 Characteristics of Kirkland Lake Ore 120 Telluride Minerais 120 Molybdenum 12 1 Surnrnary of Principal Geological Events 122 Chapter 6: Exploration at the Macassa Mine 136 Characteristics of mineralised Materid 126 Exploration Targets at Macassa 129 '04 Break Exploration 129 Exploration South of the '04 Break 133 Exploration North of the '04 Break 135 HanginPail and Footwdl Veins 136 Chapter 7: Summary and Conctusions 14 1 '04 Break 141 'OS Break 142 No. 6 Break 142 Hangingwall Veins 142 '04 North Break 143 Amikougami Creek Fault 143 Gotd Distribution 144 Summary of Principal Geological Events 144 implications for Exploration 144 References 146 List of Figures Page Figure 1.1 Location map of Kirkimd Lake. Ontario. Canada ........................................... 2 Figure 2.1 Location of the Abitibi Subprovince