The below content is from the Sea to Sky GeoTour, developed by Natural Resources Canada with the help of Geologists, Malaika Ulmi, Melanie Kelman, and Bob Turner.
A Rich Mining History
Britannia Beach sits where Britannia Creek, flowing from the mountains, has built broad gravel flats along the shores of Howe Sound. The historic mine mill, built in staircase fashion against the hillside, dominates the community. The mountain is a warren of mine tunnels that once fed ore to the mill. Over its 70-year history, the mine processed ore and shipped the metal concentrate to smelters elsewhere. Finely ground waste rock from the mill was used as landfill to extend the shoreline and carried by pipeline to the shallow offshore waters for disposal.
Finding Safe Ground
After the discovery of copper ore on Britannia Mountain, a mining camp was built in a high basin. One night in 1915, a landslide swept into a bunkhouse, killing 56 people. Looking for safer ground, the mine quarters were moved 600 metres down to Britannia Beach, on the shoreline flats by Britannia Creek. But in 1921, a flood engulfed the town during a winter storm, killing 37 people and sweeping many houses out to sea. The village was moved again, this time halfway up the mountain, where it proved to be a safer location. But, just as a reminder, Britannia Creek flooded again during a summer rainstorm in 1991, submerging the flats and burying large areas under a blanket of thick gravel. Today, rock dykes line the stream to help prevent future floods.
Billion Dollar Bonanza from a Freak of Nature?
The ores at Britannia are full of copper. They also contain iron, zinc, arsenic and other metals. Over the mine’s life, it produced metals worth about $1.3 billion in today’s dollars. How did these rich ores
come to be? Metals are generally found in trace concentrations in all rocks. The creation of a concentrated ore body required some very special circumstances in the history of the Earth. Such circumstances are so rare that an ore body might be considered a freak of nature. The Britannia Mine ores provide a good example of one such ‘freak of nature’.
Geologists believe the Britannia Mine ores formed a hundred million years ago when a hot spring deposited metals on the volcanic seafloor. Heated seawater, circulating deep through volcanic rocks, leached metals from the rocks. The metals were carried to the seafloor, where they accumulated as a large deposit. Seafloor mud and lava from nearby volcanoes covered the metals, protecting the deposit from dissolving back into the seawater. Much later, the ores were faulted and folded during several periods of uplift and mountain building. Erosion from rivers and glaciers then carved mountains, exposing part of the ores to alert prospectors and the rest is history.