Overview
Located on Granby Bay along Observatory Inlet in northwestern British Columbia, Anyox was once one of Canada’s most remote but thriving industrial mining towns. Established in the early 1910s after the discovery of rich copper-bearing massive sulfide deposits, Anyox grew rapidly under the Granby Consolidated Mining, Smelting and Power Company. The town was entirely company-owned and self-contained, complete with a large hydroelectric dam, smelter, railway, port, and housing for several thousand residents.
Mining began around 1914 at the Hidden Creek Mine, exploiting extensive volcanogenic massive sulfide (VMS) deposits hosted in altered basaltic and cherty volcanic rocks of the Early Jurassic Anyox Roof Pendant. The operation was one of the largest copper producers in Canada at the time, yielding over 760 million pounds of copper, 8 million ounces of silver, and 140,000 ounces of gold before closing in 1936 due to declining metal prices and a devastating fire that destroyed much of the town.
After abandonment, Anyox became a ghost town, with only remnants of the smelter, dam, and infrastructure remaining today. The area thus represents a unique combination of industrial heritage, geological significance, and renewable redevelopment potential in British Columbia’s mining history.
The Anyox Advantage
The Anyox district has high mineral exploration potential because it hosts a proven, fertile volcanic–sedimentary sequence with a strong record of volcanogenic massive sulfide (VMS) mineralization and remains underexplored at depth. The district’s Anyox Pendant, composed of Jurassic Hazelton-type basaltic to intermediate volcanic rocks overlain by siliceous chert and sedimentary units, is a textbook setting for copper-rich VMS systems. The historic Hidden Creek and Bonanza deposits confirm that the hydrothermal system was large and metal-rich, capable of producing ore bodies exceeding 20 million tonnes.
The presence of multiple satellite prospects (such as Double Ed, Eden, and Redwing) suggests a clustered camp-scale VMS environment, where several smaller or buried lenses could remain undiscovered along the same stratigraphic horizon. Modern geological mapping and isotopic dating have clarified the regional stratigraphy and confirmed the area’s connection to the highly prospective Hazelton arc, one of western Canada’s most prolific VMS terranes.
Despite extensive historical mining near surface, much of the district remains largely untested below 300 metres, and structural folding and faulting may have repeated or buried sulfide horizons that older, shallow exploration methods could not detect. Advances in geophysics, geochemical vectoring, and structural modelling now make it possible to identify concealed massive sulfide bodies beneath the chert horizon and altered volcanic feeders.
In summary, the Anyox district’s favorable geology, proven metal fertility, camp-scale mineralization, and modern exploration opportunities combine to make it one of British Columbia’s most promising areas for discovering a substantial new VMS deposit.
The Windy Craggy deposit, located in the Atlin Mining District of northwestern British Columbia, is one of the world’s largest and most significant examples of a Besshi-type volcanogenic massive sulfide (VMS) deposit. It occurs within the Triassic-aged Kluane Schist and Tats Group, part of the Alexander terrane, which consists of mafic volcanic rocks, black shales, and siliciclastic sediments formed in a back-arc or rifted continental margin environment.
Geological Setting
The deposit is hosted by graphitic and chloritic schists derived from submarine volcanic and sedimentary rocks that were deposited on the sea floor and later metamorphosed to greenschist–amphibolite facies. The mineralization formed at or near the seafloor as hydrothermal fluids vented through the volcanic pile, depositing sulfides in elongated, tabular lenses at the interface between mafic flows and organic-rich sediments. Subsequent regional metamorphism and deformation during the Jurassic–Cretaceous Cordilleran orogeny produced the current folded and foliated appearance of the deposit.
Orebody Characteristics
The Windy Craggy orebody is remarkably large and laterally continuous, extending for over 1.6 kilometers along strike, up to 600 meters down dip, and locally more than 200 meters thick. The mineralization is stratiform to semi-massive, forming broad sheets of sulfides parallel to bedding in the host rocks.
The main sulfide minerals include pyrrhotite, chalcopyrite, and pyrite, with lesser cobaltite, sphalerite, and arsenopyrite. Magnetite and graphite are also locally abundant. The deposit’s metal association—notably the enrichment in copper and cobalt with minor gold and silver—typifies Besshi-type systems.
Grades and Size
Windy Craggy contains a historical (pre-NI 43-101) resource estimate of approximately 297 million tonnes grading 1.38% Cu, 0.069% Co, 0.20 g/t Au, and 3.8 g/t Ag at a 0.5% copper cutoff. These grades, combined with the enormous tonnage, make it the largest known Besshi-type deposit globally and among the largest copper deposits in Canada.
Alteration and Zonation
Typical alteration includes chlorite, quartz, sericite, and carbonate, forming a broad hydrothermal halo around the massive sulfide lenses. A stockwork (stringer) zone of vein-style pyrrhotite–chalcopyrite occurs beneath the main ore horizon, representing the feeder conduit for the hydrothermal system. Vertical metal zoning is evident, with copper-rich cores grading outward into pyritic and pyrrhotitic shells.
Exploration and History
The deposit was discovered in 1957 by prospectors working for Falconbridge Nickel Mines and later explored by several major companies. Although its size and grade make it a world-class deposit, it was never mined due to its location within what later became the Tatshenshini-Alsek Provincial Park, established in 1993. Environmental concerns and the area’s wilderness designation effectively prohibit development, preserving Windy Craggy as an important scientific reference deposit for understanding Besshi-type systems.
Summary
In summary, the Windy Craggy deposit is a giant, Cu–Co-rich Besshi-type VMS system hosted in Triassic mafic–siliciclastic rocks, characterized by massive, tabular sulfide bodies, exceptional tonnage, and classic hydrothermal alteration features. It represents the end-member example of this deposit type—demonstrating how large, laterally extensive, and metal-rich seafloor hydrothermal systems can develop in back-arc basin settings.