This report on the Whitehorse Copper Belt is written by a geologist who was actively involved in mining and exploration in the district during the decade of the seventies. It includes a review of earlier data and compiles recent work, mining practice, geological concepts and constraints and problems in development and mining. Earlier reports on the district by McConnell and Kindle emphsized geology; this report concentrates on mining and development. The report was written when mining in the district was at its peak; it will be useful to those contemplating future development in the Copper Belt and for comparing the district to others. Mining in the Copper Belt may cease soon and the report was solicited by D.I.A.N.D. from Whitehorse Copper Mines as a record of mining practice and geological concepts.

Geology of the Whitehorse Copper Belt (NTS 105 D/11), southern Yukon. A compilation including a 1:25 000-scale geological map with marginal notes on bedrock geology, mineral occurrences, mineral deposits and grades of some mineral deposits.

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This publication is a field guide to the geology and mining history of the Whitehorse Copper Belt. It is designed to assist Whitehorse residents and visitors in exploring this fascinating area. Sheet 1 is a geological map with a list of suggested stops, while sheet 2 provides specific descriptions of many mineral occurrences. Stops are numbered roughly from north to south on this map, and are grouped according to their geographic location and access routes on sheet 2.

Mining activity at the Whitehorse Copper Mine has resulted in a disturbed land area of approximately 800 acres. Within this area there are about 53 acres with active slope instability and subsidence associated with the mine and underground workings. The mine is located within the city limits of Whitehorse, about six miles from the city centre. Although the mine has been decommissioned to a level acceptable to the mine inspector, there is still some concern for public safety. In addition, the current decommissioning plan is expected to result in the permanent loss of useful land from within the city limits. This report presents an assessment of the site conditions and options for reclamation to address these concerns.

A copy of this thesis is available at the EMR library – QE446.Y8 M67 1981.

This report was prepared to provide published information on the lode and placer mining industries in the Yukon during an important part of its history: mining and milling of Elsa and Keno Hill silver-lead ores had begun; significant nickel, copper, lead and zinc deposits were discovered in the White River, Vangorda Creek, and Macmillan Pass areas; and asbestos deposits were discovered. Placer mining activity continued, although pressures in the form of rising costs, and stable gold prices were forcing the industry into decline. Both the lode and placer mining industries were affected during the war years by shortages of men and equipment, although there was a great deal of attention paid to sources of tungsten, a strategic mineral. Records are not complete. Government office changes, lack of storage space and a warehouse fire may be some of the contributing factors..

The White River copper deposit, in upper Triassic Nikolai Greenstone of southwestern Yukon, is representative of the native copper-basalt association. Native copper and chalcocite are the association. Native copper and chalcocite are the most abundant ore minerals, but a substantial amount of bornite is known, as well as lesser amounts of chalcopyrite, pyrite, digenite, covellite, cuprite and native silver. These minerals are found in crosscutting fractures, amygdules, gas release tubes, small crackle zones, and as local disseminations in basalt; and although concentrated near the margins of a single glomeroporphyritic unit, are neither confined to that unit nor to a single zone within it. Two stages of copper mineralization are postulated: Stage I mineralization is thought to account for most of the native copper as a product of continental weathering of Nikolai basalts. Stage II mineralization is a much later event characterized by copper sulphides in crosscutting structures. Native copper and copper sulphides of Stage II appear to form a stable and primary product of a low grade (regional) metamorphism indicated by such minerals as chlorite, epidote, prehnite, pumpellyite, calcite analcite and apophyllite which have essentially the same mode of occurrence as primary copper minerals. Consequently, metamorphism (prehnite-pumpellyite facies) is interpreted to have been the mineralizing process. Whole-rock potassium-argon dating suggests an age no older than 120 million years for the metamorphic mineralizing event; hence, stage II mineralization post-dated host rock formation by at least 80 million years. It is probabe that many other copper occurrences in Nikolai Greenstone have formed in a similar manner. Also, it is likely that some of these mineralizing fluids could have moved higher in the stratigraphic sequence and precipitated copper minerals in other units.

The Whitehorse Copper Belt is a northwest-trending chain of copper-bearing skarn deposits, located four kilometres west of the city of Whitehorse (NTS 105 D). The belt extends parallel to the Alaska Highway for thirty kilometres, from the Crestview subdivision to the junction of the Alaska Highway and the South Klondike Highway. From the time Jack McIntyre staked the Copper King in 1898, the belt has been vigorously prospected and mined for its valuable copper, gold and silver metals.