Small-scale mining in coastal British Columbia goes back beyond written records: native copper, for example, was used before European settlement. Industrial-scale mining, however, was started by British industrialists. Coal deposits near Port Hardy on Vancouver Island are first documented in records around 1835. The Hudson’s Bay Company began mining those deposits in 1849. By 1852, the Hudson’s Bay Company had also constructed workings at British Columbia’s first recorded lode gold mine, the Early Bird mine on Moresby Island. By the 20th century, mining was an economic cornerstone. In fact, during part of its 70-year life, the Britannia mine was the largest copper producer in the British Commonwealth.
Mining is still part of the coast’s economic foundation 167 years on, although there has been a gradual shift in focus away from coal and metals to construction materials and industrial minerals. Producers of these serve local markets as well as other North American West Coast communities via barge and freighter. While the only major coal and metal mines (Myra Falls and Quinsam) on the south coast of British Columbia suspended operations in 2015 and 2016, respectively, due to low commodity prices, they may resume when markets improve. Both sites have remaining resources discovery potential. Other prospects in the region remain undeveloped and often under-explored.
From the beginning, tidewater access and growing European settlement were key industry drivers, but mining could not have flourished here without favourable geology. The geological package that underlies much of coastal British Columbia, the Wrangellia terrane, has three principal geologic constituents: a Paleozoic volcanic arc assemblage that forms the basement; a thick overlying sequence of Triassic flood basalts; and a superimposed earlyto mid-Jurassic volcanic arc assemblage. Economic mineral deposits are associated with each of these main components, as well as with overlapping assemblages and post-accretionary magmatism.
In southern coastal British Columbia, the Wrangellia terrane’s basement is known as the Sicker Group. It had depositional environments favourable to formation and preservation of Kurokotype volcanogenic massive sulphide (VMS) deposits, perhaps in a back-arc setting. Approximately 30 MINFILE occurrences within the Sicker Group have primary volcanogenic classification. Southern Wrangellia’s significant VMS producers and advanced prospects so far are in uplifts of these rocks.
The Mount Sicker Camp itself produced from three mines in the early 20th century, and the Twin J mine amalgamated these in the 1940s. Total production was over 250,000 tonnes of mostly hand sorted ore. Exploration has continued sporadically since. Although the Lara property northwest of Mount Sicker has an initial modern resource estimate, it has seen limited exploration since the 1990s.
At Buttle Lake, the centre of another large uplift of the Sicker Group basement, Myra Falls Operations (zinc-copper-leadsilver-gold) has mined and milled more than 30 million tonnes of ore since 1966. The mine, recently placed on care and maintenance, has measured and indicated resources of 7.49 megatonnes, including 4.66 megatonnes proven and probable reserves. On-site exploration continued to add to inventory until late 2015.
Overlying the Sicker Paleozoic volcanic arc is a thick sequence (up to six kilometres) of Triassic oceanic plateau flood basalts topped by limestone and clastic sediments (Vancouver Group in southern coastal British Columbia). The limestone-flood basalt contact is almost always mineralized where granitoids intrude, particularly those of the Island Plutonic Suite. MINFILE lists over 450 skarn occurrences within the Wrangellia terrane, including 47 past producers. While numerous, deposits are generally small by modern standards. The carbonate rocks are themselves a valuable resource, with several marble quarries on Vancouver Island and major limestone quarries on Texada Island. Skarns in Wrangellia are dominated by iron (magnetite) and copper types, but lead-zinc skarns are represented as well.
The heyday of British Columbia’s iron skarns were the 1950s and ’60s. Texada Mines (22 megatonnes, 1952-1976), Jedway (four megatonnes, 1962-1968), Merry Widow (3.4 megtonnes, 1957-1967), Brynnor (four megatonnes, 1962-1968) and Argonaut (3.7 megatonnes, 1951-1957) are among the more significant producers. The largest and last with significant production was Tasu, an iron skarn, with copper, gold and silver byproducts. The mine operated from 1914 to 1917 and from 1967 to 1983, with 23 million tonnes milled.
Small deposits have been considered uneconomic since the 1970s, generally unable to compete with much larger banded iron formations, now the world’s dominant sources of iron ore. Small-scale mining of magnetite was reconsidered during a recent period of high iron ore prices. There have been small amounts shipped for specialty uses.
Copper and copper gold skarns, often associated with the iron skarns, are also small by modern standards, but they can be relatively high in grade. The Old Sport mine, just north of the Merry Widow iron skarn, produced 2.6 million tonnes between 1962 and 1972 at grades of over 1.5 per cent copper and more than a gram of gold per tonne, with iron ore and silver.
Another major round of magmatism occurred beginning in the Early Jurassic Epoch, about the time of accretion to the rest of the future North American continent. Part of this event was the development of the Bonanza arc, including the Island Plutonic Suite, prospective for porphyrystyle and, in some cases, epithermal mineralization at favourable levels of erosion.
Porphyry copper occurrences are found throughout Wrangellia, but relatively few have been mined. In British Columbia, the notable producer was the Island Copper mine, which produced about 1,227 million kilograms of copper, 35,268 kilograms of gold, up to 360,800 kilograms of silver, 32 million kilograms of molybdenum and 236 kilograms of rhenium from 367 million tonnes of ore mined between 1971 and 1995. Advanced porphyry prospects along a west-northwest trend from Island Copper are objects of current exploration.
Although not part of Wrangellia in a geological sense, overlying Cretaceous sediments (Nanaimo Group) deserve an honourable mention. These host the coal deposits that started the mining industry on Vancouver Island. From the mid-19th century to the mid-20th century, the mines of the Nanaimo coal fields employed thousands and produced over 50 million tonnes of mostly thermal coal. Vancouver Island coal production has continued to 2016 with the Quinsam mine near Campbell River. It produced more than 10 million tonnes before being placed on care and maintenance in early 2016 due to low prices – it still has substantial resources.
Post accretionary magmatism, also not strictly Wrangellian, is responsible for some important mineral wealth. Historically, the Zeballos Gold Camp produced nearly half a million ounces from gold veins between 1934 and 1975. Mount Washington Copper produced briefly from 1964 to 1967, and Catface Copper has a substantial copper and molybdenum resource on the west coast of Vancouver Island. Eocene magmatism brought these latecomers to the party. On Haida Gwaii, the Harmony gold deposit (Miocene) has a resource of over three million contained ounces.