Vancouver Island’s Iron Mine: The Argonaut
Updated: Nov 19, 2022
The abandoned Argonaut Mine is a rockhounder’s dream. After driving through the backcountry southwest of Campbell River for 40 minutes (25 km), you can’t miss the giant mine dump on the side of Iron Hill. That pile is full of cool pieces!
History of the Argonaut Mine
The Argonaut deposit was discovered in the early 1900s, but the Argonaut Mine operated from 1951 to 1957 only. During that time 3.7 million tonnes of ore were mined, and 2 million kg of iron ore concentrate (56% iron) was shipped to Japan (1,2) through the Argonaut Pier in Campbell River. That isn’t a lot of iron, but what is impressive is that the deposit was basically a massive magnetite ball (1).
Iron mineralization occurred along the contact between underlying basalt and overlying marble (which is metamorphosed limestone). Both the basalt and limestone were deposited in the Late Triassic (about 210 to 205 million years ago), and the limestone was altered by hot fluids moving through the rocks sometime in the Jurassic (between 201 and 145 million years ago). The hot fluids replaced much of the limestone with iron ore (2) in the form of magnetite, and yes, it is magnetic! You can also find some beautiful garnetite samples composed of grossular / andradrite garnet. Slabbed pieces of these rocks are pretty awesome!
Rockhounding at the Argonaut Mine Dump is pretty rewarding, and you can find some truly spectacular pieces. However, the mine dump is unstable and the rocks slip down the slope quite easily. Last time I was there I left a large chunk of skin on a magnetite boulder when it slipped beneath me. If you do decide to visit, I recommend that you don't climb up the slope very far, be very careful, and be mindful of your surroundings and those around you.
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1) Panteleyev, A., and Godwin, C. I., 1995, Victoria, B.C., Geological Association of Canada, Guide to Major Mineral Deposits of Central and Northern Vancouver Island, southwestern British Columbia, Canada: A field guide for a GAC-MAC Victoria '95 field trip, 29 p.