Effective February 8, 2022, Agnico Eagle acquired all the issued and outstanding shares of Kirkland Lake Gold, resulting in Kirkland Lake Gold becoming a wholly owned subsidiary of Agnico Eagle.
Effective January 1, 2024, Agnico Eagle and Kirkland Lake Gold amalgamated, with the resulting entity continuing under the name Agnico Eagle.
Agnico Eagle has a 100% interest in the Detour Lake Complex.
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Summary:
The Detour Lake and Zone 58N deposits are considered to be examples of orogenic greenstone-hosted hydrothermal lode gold deposits.
Greenstone-hosted hydrothermal lode gold deposits are typical of the Abitibi Greenstone Belt, and in particular the gold deposits found along the Destor–Porcupine Fault Zone from Timmins, Ontario through to Destor, Québec. These deposit types are found in greenstone belts around the world and are responsible for a large proportion of past world gold production, including most of the Canadian gold production.
The majority of Archean orogenic greenstone-hosted lode gold deposits occur within volcano–plutonic domains, which are typically distributed along crustal-scale fault zones occurring along or in close proximity to terrane or sub-province boundaries (Card et al., 1989). Elongate belts of metavolcanic and some metasedimentary rocks containing subsidiary amounts of ultramafic to felsic intrusive rocks typically dominate these domains. The intrusive rocks will have typically been emplaced in multiple pulses throughout the geologic evolution of the area. Metamorphism within the belts is generally greenschist to lower amphibolite facies. The structure of the gold districts is characterized by the presence of multiple generations of structural fabrics indicating the presence of several periods of deformation.
Mineralization
There are two recognized episodes of gold mineralization at the Detour Lake and West Detour deposits.
The first episode consists of a wide and generally auriferous sulphide-poor quartz vein stockwork formed in the hanging wall of the Sunday Lake Deformation Zone. The sulphidepoor quartz vein stockworks observed in the hanging wall have sub-vertical north or south dips and are parallel to a series of east-west trending high strain zones. These veins form a weak stockwork and are boudinaged and/or folded. The second episode is a stage of gold mineralization overprinting the early auriferous stockwork, principally in the hanging wall of the Sunday Lake Deformation Zone, with a higher sulphide content.
The sulphide-rich gold mineralization predominantly fills structural sites in deformed quartz veins, fractures and veins crosscutting the foliation fabric but also in pillow breccias and selvages. The distribution of sulphide-rich mineralization is strongly controlled by the geometry of kinematic orientation (i.e., pyrite and pyrrhotite concentrations have a shallow westerly plunge similar to the plunge of the main flexure zone in the Sunday Lake Deformation Zone at an angle of about 40° (in the area of the former Campbell pit), shallowing to approximately 10° further to the west).
Detour Lake
Mineralization at Detour Lake is hosted within a broad corridor. In mine grid coordinates the mineralization extends from 16,900E to 20,650E, 19300N to 20,650N and 5,500 m elevation to 6,300 m elevation. This corresponds to a strike extent of 3.75 km, a width of 1.35 km, and an approximate elevation range of 800 m.
Mineralization
Gold is associated with quartz–carbonate–pyrite–pyrrhotite ± tourmaline veins and/or disseminated to very local semi-massive sulphides in hydrothermally-altered wall rocks. There are two main mineralized zones, defined as hanging wall mineralization and footwall mineralization.
Seven dominant mineralized domains containing most of the high-grade mineralization at the Detour Lake deposit have been defined and characterized. Gold is associated with quartz–carbonate–pyrite–pyrrhotite ± tourmaline veins and/or disseminated to very local semi-massive sulphides in hydrothermally-altered wall rocks.
Domain 51 is spatially associated with the Chert Marker Horizon known as the Main Zone. The mineralized zone consists of gold mineralization occurring along the Chert Marker Horizon in quartz and quartz–carbonate vein systems splaying from the Sunday Lake Deformation Zone.
In the East end of the Detour deposit and coincident with the Chert Marker Horizon, various talc zones occur along the footwall. With widths from 4–15 m, the talc–chlorite mineralization tends to be less continuous along strike than mineralization along the hanging wall side of the Chert Marker Horizon. Gold in the Talc Zone is dominantly associated with pyrite, pyrrhotite, and minor chalcopyrite along foliation planes, narrow discrete shears, or strain zones, and in irregular lenses.
Domain 52 is associated with hanging wall mineralization occurring in several different rock units within broad sub-vertical mineralized envelopes, which may split into several sub-vertical domains sub-parallel to the Sunday Lake Deformation Zone.
The main underground vein corridors mined historically consisted of the Q zones (Q50- Q120), which splay off the northwestern side of the Chert Marker Horizon, and comprise steeply-dipping, parallel cm-to-tens-of-cm-wide quartz-sulphide veins, and veinlets in sheeted zones locally >10 m wide. Mineralization is commonly associated with increased biotite alteration, shearing, narrow quartz veining and minor pyrite or pyrrhotite.
Further to the west lies the “QK Zone” as denoted by Placer Dome. This mineralization is associated with narrow parallel to sub-parallel quartz veins, quartz boudins and sulphiderich veins/breccias with adjacent silicification and potassic alteration envelopes.
Further to the north and hanging wall to the Q-zones, Domain 53 is spatially associated with highly-strained corridors at the contacts between pillowed and massive mafic flows encompassing higher grade mineralized zones. These broad zones contain variable amounts of quartz and pyrite, and are controlled mainly by east-west trending, moderately north-dipping folds and shear structures which plunge at a shallow angle to the west.
Identified as “M Zone” by Placer Dome, Domain 55 encompasses high-grade areas towards the west end of the deposit, mostly following the west extension of the chloritic greenstone unit. Spatially, Domain 55 lies approximately 400– 500 m north of the Chert Marker Horizon and is a westerly-trending gold system that is spatially associated with the margins of the chloritic greenstone unit.
Domain 54 is located west of Domain 55. Both of these amphibole–chlorite schist stratigraphic horizons and associated gold mineralization were traced by drilling for approximately 5 km. The footwall and hanging wall sequence of the chlorite schist is variably biotite altered with abundant fractures, with a well-defined foliation which contains local quartz veining with associated pyrite, pyrrhotite and rarely, chalcopyrite. The mineralized zones appear lensoidal and plunge 20° west. Mineralized lenses vary from 5–50 m in true width.
Domain 56 has similar characteristics to Domain 53, encompassing high-grade mineralized zones within partially to highly-strained corridors at the contacts between pillowed and massive mafic rocks. They appear to be semiparallel to the chloritic greenstone, and are predominantly narrow east-west subvertical to 65º north–northwest-dipping structures.
Domain 57 is spatially associated with hanging wall high-grade east–northeast to west–southwest mineralized zones. Gold mineralization is concentrated within potassic-altered mafic volcanic units containing relatively weak quartz vein stockwork with low pyrite and pyrrhotite content exhibiting moderate to strong shearing.
Zone 58N
The Zone 58N mineralized system has been intersected over an east–west strike length of 450 m, from surface to a depth of 800 m, and the mineralized system remains open along strike and at depth. The width of the mineralization is variable, ranging from 4 m to >100 m at the centre of the deposit.
Visible gold is often present and occurs within coarse pyrite or as free gold within quartz. Sulphide mineralization associated with gold ranges from 0.5–5% pyrite with minor chalcopyrite, bismuth-tellurides, molybdenite and scheelite.