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Occurrence Details


Occurrence Number
105D 210
Occurrence Name
Grafter
Occurrence Type
Hard-rock
Status
Past Producer


General Information

Primary Commodities: silver, gold, copper
Aliases: Whitehorse Copper
Deposit Type(s): Skarn
Location(s): 60.670510 N, -135.124060 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 Grafter deposit and mine is located in close proximity to the Best Chance deposit and therefore the geology is assumed to be quite similar. The geological description for the Best Chance deposit is given below as reference:

The Best Chance deposit is exposed as a large outcrop of magnetite and skarn over a maximum length of 420 ft (128 m) to the north and widths up to 80 ft (24 m). The deposit is bounded by limestone on the west and granite on the east. The ore within the garnet-magnetite skarn consists of chalcopyrite, bornite and sections of massive magnetite. The major part of the copper mineralization is concentrated near the roof or around a large unreplaced lens of limestone within the skarn and the copper values are frequently found in massive magnetite.

Production at the Grafter mine was 1 800 tonnes at 7.0 % Cu between 1899 – 1907, and 10 400 tonnes at 6.0% Cu between 1915 – 1917. The ore also contains small amount of Au and Ag. 

Location Map

Last Updated: Apr 11, 2019

Work History

Year Work Type Comment
1990 Drilling: Reverse Circulation 7 holes completed
1990 Geochemistry: Drill Cuttings
1990 Ground Geophysics: Magnetics
1990 Lab Work/Physical Studies: Petrographic
1973 Geology: Bedrock Mapping
1973 Lab Work/Physical Studies: Petrographic
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
092887 1990 Report on the 1990 Drill Program. Aurora Gold Ltd. Property, Whitehorse Copper Belt Reverse Circulation - Drilling, Drill Cuttings - Geochemistry, Magnetics - Ground Geophysics, Petrographic - Lab Work/Physical Studies 7 849.78
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
062227 1966 An Evaluation of the New imperial Mines Ltd. Feasibility - Studies
091123 1964 Summary of assessment work for 316 claims Diamond - Drilling 46 3652.57

Related References

Number Title Page(s) Document Type
1984-1 The Whitehorse Copper Belt - A Compilation Open File (Geological - Bedrock)
092887 Report on the 1990 Drill Program. Aurora Gold Ltd. Property, Whitehorse Copper Belt Assessment Report
091123 Summary of assessment work for 316 claims Assessment Report
062227 An Evaluation of the New imperial Mines Ltd. Assessment Report
062018 Preliminary Report on Geological Control to Ore Distribution in the Whitehorse Copper Belt Assessment Report
ARMC004821 Map of Best Chance/Grafter Geoscience Map (Geological - Bedrock)
ARMC004892 Induced polarisation report on the Grafter and Best Chance deposit - Whitehorse Copper Belt Report
ARMC004822 Sketch map of Grafter mine Geoscience Map (General)
Citations
Kindle, E.D., “Summary of Research: Field, 1962”; Geological Survey of Canada, Paper no. 63-1, 1963, https://doi.org/10.4095/121464 (Open Access)

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