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Occurrence Details


Occurrence Number
105D 206
Occurrence Name
Big Chief
Occurrence Type
Hard-rock
Status
Deposit


General Information

Secondary Commodities: copper, gold
Aliases: Whitehorse Copper
Deposit Type(s): Skarn
Location(s): 60.638120 N, -135.064280 W
NTS Mapsheet(s): 105D11
Hand Samples Available at YGS: No

Capsule

The Whitehorse Copper Belt is located west of Whitehorse and contains 30+ mines, deposits and showings. Many of the occurrences in the Copper Belt are skarns. The skarns form on or near the contact between the Whitehorse batholith and the Lewes River group. The Whitehorse batholith is commonly a grey coarse-grained hornblende granite and ranges from quartz monzonite to granodiorite to diorite. The Lewes River group contains numerous different rock types, most importantly of which is the limestone group, which is essential in the formation of skarns in the area.  A small number of occurrences within the Copper Belt are vein and/or replacement and occur within the Whitehorse batholith granite.

The Middle Chief and Big Chief deposits are within 2000 ft (610 m) of the Little Chief deposits. Therefore, although there is little detailed work done on the Middle and Big Chief deposits, it is assumed that they display much of the same characteristics. The Middle and Big Chief deposits are considered a faulted northward extension of the Little Chief deposit. The description below is from the Little Chief Deposit:

"The Little Chief deposit is within the Hancock member of the Aksala formation in the Lewes River Group.  The skarn occurs along the northwest trending contact between the granodiorite and the limestone and the ore is about 600 ft. (182.88 m) along strike and an average of 80 ft. (24.384 m) in width.

The Little Chief mine display features of both endoskarns and exoskarns however, the endoskarn is subordinate to the exoskarn. The skarns of the contact zone developed in three stages; the pyroxene Stage, The Magnetite-Andradite Stage, and the Serpentine-Chlorite-Epidote Stage. The skarn is believed to have formed between 525-300 °C with early contact metamorphic minerals forming  in a high CO2 environment and skarn minerals forming in a low CO2 environment. The deposit shows characteristics of both infiltrational and diffusional metasomatic features. The deposit has been described as a bimetasomatic skarn in calcareous rocks onto which an infiltrational skarn has been imposed.

Ore minerals present within the deposit include bornite, chalcopyrite, valeriite and magnetite.  During drilling, encouraging copper values have been intersected down to an elevation of 1430 ft (435.9 m). Total production at the Little Chief mine between operating years 1967-1982 was 8 536 400 tonnes (Includes production from the Middle Chief deposit)  and the reported grade between 1972-1982 was 1.53 Cu%, 0.75 g/t Au and 9.16 g/t Ag."

Location Map

Last Updated: Apr 11, 2019

Work History

Year Work Type Comment
1974 Drilling: Diamond
1974 Geochemistry: Drill Core
1974 Ground Geophysics: IP
1973 Drilling: Diamond 2 holes completed
1973 Geology: Bedrock Mapping
1973 Lab Work/Physical Studies: Petrographic
1973 Pre-existing Data: Research/Summarize
1969 Studies: Feasibility
1966 Studies: Feasibility
1964 Drilling: Diamond

Regional Geology - Terrane

Group: Intermontane
Affinity: W Laurentia
Name: Stikinia
Realm: peri-Laurentian


Regional Geology - Bedrock

Supergroup:
Group/Suite: Whitehorse
Formation:
Member:
Terrane:
Period Max: Cretaceous
Age Max: 112 MA
Period Min: Cretaceous
Age Min: 105 MA
Rock Major: granodiorite/quartz diorite
Rock Minor:
Reference: Hart & Radloff (1990) - YGS OF 1990-4
Geological Unit (1M): mKW
Geological Unit (250K): mKgW

Assessment Reports that overlap occurrence

Report Number Year Title Worktypes Holes Drilled Meters Drilled
061173 1974 Report on Exploratory Work on Whitehorse Copper Belt Diamond - Drilling, Drill Core - Geochemistry, IP - Ground Geophysics 10 2222.29
060525 1973 [Proposed Surface Drill Programs on the Little Chief-Big Chief-Valerie Properties] Research/Summarize - Pre-existing Data
062018 1973 Preliminary Report on Geological Control to Ore Distribution in the Whitehorse Copper Belt Reverse Circulation - Drilling, Bedrock Mapping - Geology, Petrographic - Lab Work/Physical Studies 665 5555
062228 1969 Feasibility Study for the Underground Development of the Little Chief Orebody Feasibility - Studies
062227 1966 An Evaluation of the New imperial Mines Ltd. Feasibility - Studies
062226 1965 Feasibility Study for 2000 Ted Copper Ore Mine, Concentrator Plant and Related Services Feasibility - Studies
091123 1964 Summary of assessment work for 316 claims Diamond - Drilling 46 3652.57

Related References

Number Title Page(s) Document Type
091123 Summary of assessment work for 316 claims Assessment Report
062018 Preliminary Report on Geological Control to Ore Distribution in the Whitehorse Copper Belt Assessment Report
060525 [Proposed Surface Drill Programs on the Little Chief-Big Chief-Valerie Properties] Assessment Report
1984-1 The Whitehorse Copper Belt - A Compilation Open File (Geological - Bedrock)
062227 An Evaluation of the New imperial Mines Ltd. Assessment Report
062228 Feasibility Study for the Underground Development of the Little Chief Orebody Assessment Report
061173 Report on Exploratory Work on Whitehorse Copper Belt Assessment Report
ARMC004797 Map showing Valerie, Big Chief, Little Chief Geoscience Map (General)
ARMC004796 Map of Little Chief to Big Chief - DDH BC 1 to 6 drilled Geoscience Map (Geological - Bedrock)
ARMC004792 Exploration composite map - Middle-Big Chief Geoscience Map (General)
Citations

Drill Core at YGS Core Library

Number Property Year Drilled Core Size Photos Data
LC-109 Little Chief 1973 AQ 22 0

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