Tiny gold grains could hold key to copper deposit 'DNA'

Vancouver, BC - November 2, 2017 - An innovative technique to analyze gold grains finer than a human hair -- and even smaller minerals trapped inside them -- with a probing instrument and scanning electron microscope could help to find new copper deposits, according to new results from research funded by Geoscience BC.

Tiny grains of gold are often found in the natural environment and can be analysed to help locate new mineral deposits. The study, completed by Dr. Rob Chapman and masters student Thomas Mileham from the Ores and Minerals Group, University of Leeds, UK, analyzed the composition of gold grains formed in British Columbia alkalic copper-gold porphyry deposits, the deposit type that provides over half of the world's copper. The researchers studied gold grains from the Mt Milligan, Mt Polley, Ajax and Copper Mountain deposits and surrounding areas.

"Explorers routinely collect stream sediment, soil and till samples that contain gold grains when searching for new deposits," said Geoscience BC Vice President of Minerals and Mining Bruce Madu. "The information generated from this project will make those samples even more useful, and may help us find future copper mines."

"When we see elevated palladium and mercury in the gold grains, we can be fairly sure the gold is from an alkalic copper-gold deposit," said Dr. Rob Chapman. "We analyzed over 700 gold grains collected from ore rock at the mines, or from nearby streams, and observed this signature in grains from every locality."

Chapman said that researchers can now distinguish between gold grains that come from orogenic, calc-alkalic, and alkalic copper gold porphyry deposit types in the North American Cordillera -- the mountains that form the spine of North America.

He added: "Our aim is to develop and establish a new exploration methodology using gold as an indicator mineral."

The knowledge contained the new Microchemical signatures of gold in Cu-Au porphyries, British Columbia, Canada report will help identify hidden mineral deposits. "Using the knowledge from this study could will help discover copper deposits right here in BC," said Madu. "That copper is vital for the electronics and devices needed as we transition to a 'green' economy."

Accessing Information

Final reports are now available on the Geoscience BC website www.geosciencebc.com, which includes the free Earth Science Viewer web mapping application.

Microchemical signatures of gold in Cu-Au porphyries, British Columbia, Canada

View 2014-007 project page View Project 2014-007 in Earth Science Viewer

About the University of Leeds
You can find out more about the UoL Ore Research Group at http://www.see.leeds.ac.uk/research/iag/minerals-and-ore-geology/

About Geoscience BC
Geoscience BC is an independent, non-profit organization that generates earth science information in collaboration with First Nations, local communities, governments, academia and the resource sector. Our independent earth science enables informed resource management decisions. Geoscience BC gratefully acknowledges the financial support of the Province of British Columbia.

For additional information, please contact:

Richard Truman
Geoscience BC

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