Bornite

This specimen contains primarily bornite and chalcopyrite with apatite. The first two minerals are primary sources of copper ore.

Bornite is an important copper ore mineral found in many different types of copper deposit. It is also known as peacock ore because of its iridescent purple-blue-green tarnish. Fresh bornite, however, is copper red. Bornite commonly occurs with other copper sulphide minerals such as chalcocite and weathers, or “oxidizes”, to malachite.

Chalcopyrite is the most common ore mineral for copper. Chalco comes from the Greek word chalko, meaning copper. Chalcopyrite is commonly found in sulphide deposits in most ore-forming environments. Characteristic deep brass yellow colour and iridescent green-to-purple weathering surfaces distinguish chalcopyrite from gold and sulphides such as pyrite. 

This sample is from Copper Mountain, about 20 km south of Princeton in southern BC.

Copper ore was first discovered in the area in the 1880s and attracted miners who quickly settled in two mining camps, “Volacanic” Brown’s Camp and E. Voight’s Camp. These soon merged to become the town of Copper Mountain, which had its own post office and general store. Early miners extracted ore from underground workings, but most of the ore was mined from several open pits. The Copper Mountain mine was in production from the mid 1920s to 1957, when low copper prices and a dispute with the local railway company shut down production because operating costs were too high. Mining started up again in the mid 1960s and continued until 1996, when low prices closed the mine again. For a long time it seemed that was the end of mining at Copper Mountain, but production resumed in 2011 and continues to this day.

At Copper Mountain, copper ore is mined from several ore bodies contain that the copper minerals bornite and chalcopyrite, as well as pyrite. As is common at porphyry-type deposits like Copper Mountain, small amounts of gold and silver are also produced.

From the mid 1900s to 1996, over 2 billion pounds of copper were extracted from the various pits at the Copper Mountain mine. In 2017, the mine produced 75.8 million pounds of copper, 734,000 grams of gold and 8,616,000 grams of silver from 72.6 million tonnes of ore.

 

Specimen Information

Store: Pacific Museum of the Earth, University of British Columbia

Collection: Sutton-Thompson Collection

Accession #: S74-983

Primary Mineral: Bornite

Secondary Mineral: Chalcopyrite, Apatite

Site Locality: Copper Mountain

Location: Princeton, British Columbia

Special Features: n/a

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