Canada

Carmacks Project

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Categories

Overview

Mine TypeOpen Pit
StagePermitting
Commodities
  • Copper
  • Gold
  • Silver
  • Molybdenum
Mining Method
  • Truck & Shovel / Loader
Mine Life... Lock
SnapshotThe Granite Creek Copper flagship asset is the Carmacks and Carmacks North (Carmacks North was previously known as the Stu project) copper-goldsilver project (the “Carmacks Property”).

On August 23, 2023, the Company announced positive preliminary results of metallurgical testing designed to increase overall copper recovery at its Carmacks project. The work is an important first step in realizing an additional $180M of Net Present Value that is identified in the Preliminary Economic Assessment (“PEA”) study as potential in a combined sulphide-oxide recovery system, with total copper recovery increasing by 20% from the current projected 64% to 77% total copper recovery.

Owners

SourceSource
CompanyInterestOwnership
Granite Creek Copper Ltd. 100 % Indirect
Carmacks mine project is 100% owned by Granite Creek.

Contractors

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Deposit type

  • Porphyry
  • Metamorphic

Summary:

The Cu-Au-Ag deposits of the Carmacks Project, and the related Minto deposit, are considered rare examples of metamorphosed porphyry Cu systems (Kovacs et al., 2020).

The following section regrading the Carmacks Project mineralization has been modified from Kovacs (2018). Modifications have been made based on recent work by Granite Creek.

Mineralization of the Carmacks Copper Cu-Au-Ag deposit occurs within a 3 km–long, north-northwest trending belt that is separated into a northern Zone 1, 4 & 7, central Zones 2000S and southern zones 13 and 12.

Three different varieties of hypogene copper mineralization are recognized, with distinct mineralogical and textural characteristics: disseminated, foliaform, and net textured.

Disseminated copper sulphide mineralization is interpreted to be the least modified by metamorphism because it typically occurs in the undeformed metamorphic lithologies and augite gabbro. Disseminated chalcopyrite and pyrite comprise a minor portion of the hypogene mineralization and is typical in the undeformed, hornblende porphyroblastic amphibolite, granoblastic quartz-plagioclase-biotite schist, and augite gabbro. Disseminated copper sulphide minerals also occur in leucosome within the quartz- plagioclase-biotite schist unit. Chalcopyrite is typically fine-grained (0.3-0.7 mm) and occurs as anhedral to wavy, skeletal grains intergrown with also fine-grained (0.1 mm), minor subhedral pyrite.

Foliaform copper sulphides are restricted to the amphibolite and the quartz-plagioclase-biotite schist and occur as chalcopyrite-dominant stringers that parallel the dominant foliation (). Chalcopyrite is fine-grained (0.3-0.5 mm) and forms elongated anhedral grains. Bornite is less common in the foliaform mineralization, but where present forms fine-grained (0.2-0.5 mm), anhedral, blebby intergrowth with foliaform chalcopyrite. Pyrite intergrown with chalcopyrite is rare, but it is euhedral where present. The foliaform nature of copper sulphides is interpreted as the result of Late Triassic deformation and temporally associated upper amphibolite facies metamorphism.

In contrast, mineralization hosted by the migmatite occurs as net-textured intergrowths of bornite and chalcopyrite, which comprises as much as 20%-40% of the rock by volume, with typical bornite-chalcopyrite ratios of 3:1. Pyrite is absent in the migmatite. Bornite and chalcopyrite occur together in irregular nettextured domains up to 2–4 mm across forming low interfacial angles that are clearly interstitial with respect to silicate grains. Both chalcopyrite and bornite are commonly replaced by digenite along 50 mm-wide fractures and grain margins and is interpreted as the latest copper phase due to secondary oxidation. Net-textured bornite is especially abundant in melanosome, where it typically forms higher-grade (1-2% Cu) domains. The net-textured domains contain numerous inclusions of fine- grained native bismuth, Au-Ag tellurides, and bismuth tellurides. Molybdenite is commonly intergrown with net-textured copper sulphides and occurs as kinked anhedral grains separated along cleavage surfaces or as euhedral undeformed grains.

The pyrite content of the deposit is notably low (~1%). Gold is principally associated with bornite and occurs as 10-20 µm inclusions of electrum or native gold, or more commonly as gold telluride (calaverite), or solidsolution gold-silver tellurides, as determined by SEM-EDS spectrometry. Silver is present as hessite inclusions in bornite. Because gold and silver are typically associated with bornite, the bornite-chalcopyrite ± digenite zone is precious - metal enriched and the migmatite contains higher copper, gold, and silver grades than the amphibolite and quartz-plagioclase-biotite schist sequence.

Copper grades increase progressively northwards from the lower grade material found in the southern deposit Zone 12 and 13 deposits through to the highest-grade material at the Zone 1 deposit. This change in grade is interpreted to be caused by the increasing northward metamorphic gradient of the inliers which is also reflected in the general depth of emplacement of the batholiths.

Deep oxidation of the deposits has oxidized primary sulphides to copper oxides and copper carbonates with approximately 15% of the copper in the oxide domain occurring as remnant copper sulphide, in the form of chalcopyrite. This oxidation profile has led to the formation of an oxide cap that can be over 200 metres thick at zone 1 to ~40m thin in Zone 12. The majority of the copper found in oxide are in the form of the secondary minerals malachite, cuprite, azurite, tenorite (copper limonite) and crednerite with minor other secondary copper minerals (covellite, digenite, chalcocite). Native copper occurs as dendritic secondary precipitates on fractures, disseminated grains or thin veinlets. Other secondary minerals include limonite, goethite, specular hematite and gypsum.

Within the oxidized portion of the deposit, pyrite is virtually absent and pyrrhotite is absent. Oxidation has resulted in 1% to 3% pore space and the rock is quite permeable. Secondary copper and iron minerals line and in-fill cavities, form both irregular and coliform masses, and fill fractures and rim sulphides.

Gold occurs as native grains, most commonly in cavities with limonite or in limonite adjacent to sulphides, but also in malachite, plagioclase, chlorite, and rarely in quartz grains. Gold is rarely greater than five microns in size.

Reserves

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Mining Methods

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Comminution

Crushers and Mills

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Processing

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Production

CommodityUnitsAvg. AnnualLOM
Copper M lbs 27257
Gold koz 12118
Silver koz 1521,440
Copper Equivalent M lbs 34850
All production numbers are expressed as metal in copper conc..

Operational metrics

Metrics
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Annual processing rate  ....  Subscribe
Annual processing capacity  ....  Subscribe
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Waste tonnes, LOM  ....  Subscribe
Ore tonnes mined, LOM  ....  Subscribe
Total tonnes mined, LOM  ....  Subscribe
Tonnes processed, LOM  ....  Subscribe
* According to 2023 study.

Production Costs

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

Operating Costs

Currency2023
OP mining costs ($/t mined) CAD 3.16 *  
OP mining costs ($/t milled) CAD  ....  Subscribe
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
Initial CapEx $M CAD  ......  Subscribe
Sustaining CapEx $M CAD  ......  Subscribe
Total CapEx $M CAD  ......  Subscribe
OP OpEx $M CAD  ......  Subscribe
Processing OpEx $M CAD 389.3
Refining costs $M CAD  ......  Subscribe
G&A costs $M CAD 104.8
Total OpEx $M CAD  ......  Subscribe
Total Taxes $M CAD  ......  Subscribe
Royalty payments $M CAD  ......  Subscribe
Gross revenue (LOM) $M CAD  ......  Subscribe
Net revenue (LOM) $M CAD  ......  Subscribe
Pre-tax Cash Flow (LOM) $M CAD  ......  Subscribe
After-tax Cash Flow (LOM) $M CAD  ......  Subscribe
Pre-tax NPV @ 5% $M CAD  ......  Subscribe
Pre-tax NPV @ 10% $M CAD  ......  Subscribe
Pre-tax NPV @ 8% $M CAD  ......  Subscribe
After-tax NPV @ 5% $M CAD  ......  Subscribe
After-tax NPV @ 10% $M CAD  ......  Subscribe
After-tax NPV @ 8% $M CAD  ......  Subscribe
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After-tax payback period, years  ......  Subscribe

Heavy Mobile Equipment

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Personnel

Mine Management

Job TitleNamePhoneProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Mar 6, 2023
....................... Subscription required ....................... Subscription required Subscription required Jan 19, 2023
....................... Subscription required ....................... Subscription required ........... Subscription required Subscription required Jan 18, 2024
....................... Subscription required ....................... Subscription required Subscription required Jan 18, 2024

EmployeesContractorsTotal WorkforceYear
...... Subscription required ...... Subscription required ...... Subscription required 2023

Aerial view:

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