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Sleeping Giant Mine

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Mine TypeUnderground
  • Gold
Mining Method
  • Shrinkage stoping
  • Room-and-pillar
  • Longhole stoping
Mine Life... Lock
SnapshotThe Sleeping Giant mine has a mining lease as well as environmental certificates of authorization to extract up to 750 tonnes per day from its underground mine.

In 2024, operations at the Sleeping Giant project continue with underground drilling to increase total mineral resources and subsequently, complete an economic pre-feasibility study. Underground teams are busy rehabilitating underground infrastructures as well as hoisting mineralized material to supply the ore processing plant. Abcourt therefore began pouring gold bar from the Sleeping Giant project in May 2024. Over the coming months, Abcourt plans to continue supplying the mill with material from its Sleeping Giant project.


Abcourt Mines Inc. 100 % Indirect
Abcourt is the sole owner of all leases and mining titles on the Sleeping Giant Property.



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Deposit type

  • VMS


Sleeping Giant is a sulphide-rich lode gold deposit of volcanogenic affinity. In a geochemistry study of the volcanogenic massive sulphide (VMS) deposits in the Abitibi belt, Gaboury and Pearson (2008) classified the Sleeping Giant Rhyolite as “F1 type”, which includes VMS deposits rich in gold and silver. Such deposits, which have the particularity of being spatially isolated, are probably the result of local hydrothermal processes (Gaboury, 2004). The Sleeping Giant deposit displays atypical characteristics of orogenic Archean deposits associated with major faults. According to Gaboury (1999), gold-bearing veins formed in subhorizontal strata shortly after QFP injections but before the end of mafic magmatism. All rock types, including gold-bearing veins, have been affected by regional ductile deformation (folding of strata and development of schistosity) and metamorphism to greenschist facies.

The mine sequence is represented by a volcano-sedimentary succession intruded by a felsic complex and transected by late hornblende-rich dykes. Strata strike predominantly E-W and dip steeply to the south, forming a single homoclinal stratigraphic succession. All the rock types have been metamorphosed to greenschist facies, but the prefix "meta" is omitted in the following sections to simplify the rock nomenclatures.

Mineralization styles
Gold-bearing veins
Gold-sulphide-quartz veins are generally massive and range from a few centimetres to 2 m thick (average of 50 cm for the mined veins). The veins are rich in gold with assays commonly > 100 g/t Au (unpublished data, Cambior Inc.). The vein contacts range from sharp, planar and free of surrounding planar fabric to undulose and schistose. Branching of main veins is a common phenomenon but does not show consistent attitudes. Veins terminate laterally through pinching out or arborescent multibranching veinlets.

Stratabound mineralization
Stratabound mineralization corresponds to gold-bearing segments of sedimentary horizons in which three main modes of occurrence have been observed: (1) subconcordant, millimetre- to centimetre-wide quartz-sulphide veinlets (the most common form); (2) concordant, parallel layers of massive sulphides; and, (3) disseminated sulphides, mainly pyrrhotite, pyrite and marcasite, with minor chalcopyrite and sphalerite. The sulphide layers are a few millimetres thick and are mainly composed of pyrrhotite and pyrite, with lesser chalcopyrite and sphalerite. In thin section, remnant magnetite grains and pseudomorphs suggest that the sulphide layers, and in part the disseminated sulphides, formed by the hydrothermal replacement of magnetite iron formations. Mineralization occurrences are related to both compositional (e.g., magnetite and silica contents) and rheological characteristics (e.g., bedding attributes and competency contrasts between individual beds) in the sedimentary horizons, and the relative proportions of which are variable. Some sulphide layers were mapped as the lateral termination of subconcordant quartz-sulphide veinlets. High-grade gold mineralization (>100 g/t Au) is restricted to the narrow quartzsulphide veinlets and sulphide layers.

SE-NW veinlet arrays
Arrays of gold-bearing veinlets occur in close spatial association with the gold-bearing veins hosted by mafic sills. These 1-cm to 4-cm-wide quartz-sulphide veinlets strike consistently SE-NW and dip steeply to the NE, parallel to the QFP dykes. Individual veinlets are planar and exhibit a regular distribution, with spacings of 1 to 2 m. The SE-NW veinlets generally have a consistent width, but some are boudinaged in vertical section. The grade of the veinlets ranges from 1 to 10 g/t Au.

Veining within the QFP dykes
This style of mineralization occurs solely within the QFP felsic dyke group, where it forms multiple, millimetre-wide quartz and sulphide veinlets and disseminated auriferous pyrite Crosscutting relationships indicate episodic veining injections within the dykes. Mineralization within the QFP dykes is a mine-scale phenomenon, but it is best developed in close spatial association with the gold-bearing veins. Systematic assays have revealed erratic gold grades ranging from nil to hundreds of g/t Au.

Gold mineralization with economic potential is mainly restricted to the volcanosedimentary succession bounding the dacitic intrusion. At the mine-scale, mineralized zones are scattered within a 1-km2 surface area. For the gold-bearing veins, there is a substantial difference in attitude and size depending on their position relative to the dacitic intrusion. North of the dacitic intrusion, the veins strike mainly E-W with a steep dip (> 75°) to the south. Their lateral extent ranges from 100 to 200 m with a vertical extent in excess of 700 m, yielding a ratio (lateral/vertical) of about 1:7.

Deformation affecting the host rocks is expressed by (1) the subvertical attitude of the volcanic strata; (2) the development of ductile planar and linear elements; (3) local mesoscopic folds; and (4) subhorizontal extensional calcite veinlets. These features are related to the regional deformation event. Subsequent deformation includes local shear zones and late brittle faults.



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Mining Methods


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Crushers and Mills


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CommodityProductUnitsAvg. AnnualLOM
Gold Metal in doré koz 30181
Gold Payable metal koz 181

Operational metrics

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Waste tonnes, LOM  ....  Subscribe
Ore tonnes mined, LOM  ....  Subscribe
Tonnes processed, LOM  ....  Subscribe
* According to 2023 study.

Production Costs

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All-in sustaining costs (AISC) Gold USD  ....  Subscribe
Assumed price Gold USD  ....  Subscribe
* According to 2023 study / presentation.

Operating Costs

UG mining costs ($/t mined) CAD 226.24 *  
Processing costs ($/t milled) CAD  ....  Subscribe
G&A ($/t milled) CAD  ....  Subscribe
Total operating costs ($/t milled) CAD  ....  Subscribe
* According to 2023 study.

Project Costs

MetricsUnitsLOM Total
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UG OpEx $M CAD  ......  Subscribe
Processing OpEx $M CAD 32.3
Refining and treatment costs $M CAD  ......  Subscribe
G&A costs $M CAD 11.6
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Heavy Mobile Equipment


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Mine Management

Job TitleNameEmailProfileRef. Date
....................... Subscription required ....................... Subscription required ........... Subscription required Subscription required Oct 2, 2023
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Aerial view:


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