In April 2022, Tony Kemp, Giulia Consuma, Brian Tattitch, and Steffen Hagemann from the University of Western Australia (UWA) – Centre for Exploration Targeting (CET) visited Arizona to study high-grade, hypogene porphyry copper deposits as part of the two BHP-funded projects ‘Mineral Messengers’ and ‘Chemical Triggers’.
Arizona is home to some of the world’s largest copper deposits and represents an exceptional natural laboratory to foster our understanding of how copper concentrates in the earth’s crust, deep below the ground surface. Developing a better sense of how high-grade hypogene copper mineralisation occurs is necessary to address the world’s surging demand for copper and support the global transition to sustainable technologies (electric vehicles, wind turbines etc.).
For the first week, the UWA team visited the underground Resolution porphyry Cu-Mo deposit located near the town of Superior, Arizona. Resolution Copper is jointly owned by Rio Tinto and BHP and represents one of the largest undeveloped copper projects in the world, with the potential to become the largest copper producer in North America (bhp.com). The deposit formed from the interaction of saline, metal-bearing fluids degassed around 70 million years ago from uprising cooling magma, into ancient (>1 Billion years old) overlying host rocks adjacent to the main pluton. Successive faulting, erosion, and weathering processes prompted the exposure of the deposit and further concentration of copper. In Resolution, the team logged and selected targeted drill cores that will be investigated with the analytical facilities available at UWA.
The second week saw the team complete complementary fieldwork in the areas surrounding the Resolution deposit. The team examined the Pioneer and Globe-Miami districts, and the historical San Manuel hypogene and supergene porphyry copper mine, in addition to other associated magmatic suites.
The team ‘Mineral Messengers’ is now focusing on performing mineral-scale investigations of the selected samples to detect whether the high-grade hypogene copper mineralisation is associated with a characteristic volatile component signature. At the same time, the team ‘Chemical Triggers’ is running laboratory experiments to simulate the natural processes that may have prompted the mineralisation of the Resolution Copper deposit.
Watch for future updates about results from this trip and our upcoming trip to Chile!
Group photo: From left to right: Tony Kemp (UWA), Brian Tattitch (UWA), Steffen Hagemann (UWA), Adam Gorecki (Superintendent Exploration at BHP), Giulia Consuma (UWA). In the background, the Apache Leap cliff.
Picture credit: Tom Lamont (University of Bristol).
