Throughout 2019, the project team focussed on collecting new samples from the Lady Annie copper deposit and Starra IOCG deposit as part of the mineral chemistry ‘footprint’ studies being carried out to identify mineral chemistry vectors towards ore. A new PhD student (Max Hohl) joined the research team to work on the Starra IOCG deposit.

One of the key findings revealed by the project to date is a distinctive and systematic trend in the chemistry of pyrite associated with mineralisation throughout many of the IOCG deposits of northwest Queensland, which shows a distinct transition from high Co-low Ni to high Ni-low Co pyrite with time. This signature is similar to IOCG deposits from South America, suggesting that it may be a distinctive signature of IOCG deposits more broadly, which could be used by explorers to test whether pyrite encountered in drill core is likely to be associated with an IOCG mineral system.

Detailed study of carbonate-hosted copper mineralisation at the Lady Annie deposit reveals that copper mineralisation is associated with a late generation of carbonate which crosscuts earlier formed oscillatory zoned dolomite. This carbonate has a distinctive ‘fingerprint’ of high Mn, which is a common signature of mineralisation-associated carbonate cements in many types of carbonate-hosted ore deposit. Work is continuing to establish how far this elevated Mn signature in carbonate cements can be traced away from the Lady Annie Deposit.

In 2017, CODES was invited to participate in a new research initiative, the Strategic Resources Exploration Program, which is being led by the Geological Survey of Queensland (Department of Natural Resources and Mines) and the University of Queensland. This research program involves a consortium of researchers from several organisations, including CSIRO and James Cook University, and aims to stimulate exploration and discovery of new resources in the Northwest Queensland Mineral Province. CODES is a key participant in this collaboration. Shaun Barker began work on this project in 2018. Shaun has significant experience in pyrite and carbonate mineral chemistry from sediment-hosted hydrothermal systems. Jonathan Cloutier was appointed in late 2018 from the University of St Andrews, Scotland, and will begin work in February 2019 on this project as a postdoctoral research fellow alongside Jeff Steadman, who began work on this project in late 2017.

In 2018, CODES began generating new mineral chemistry data from a variety of IOCG (Ernest Henry, SWAN and others) and sedimenthosted base metal deposits (Lady Loretta) in NW Queensland, with an initial focus on magnetite and pyrite minerals. Our initial results collected in 2017 from the Lady Loretta deposit demonstrated that pyrite in the ore horizon at Lady Loretta shares similar chemical characteristics to pyrite from that defined from the HYC deposit (recently published CODES research by Indrani Mukherjee and Ross Large). Meanwhile, pyrite from the SWAN IOCG system contains high concentrations of cobalt. Gold and copper in the SWAN deposit are found within late fractures in both pyrite and magnetite, providing valuable paragenetic information on the relative timing of Cu-Au mineralisation at that deposit.

As the mineral chemistry project continues in 2019, the trace element chemistry of a variety of other minerals including chlorite, epidote, carbonate minerals and apatite will be evaluated. Through our mineral chemistry analyses, we seek to extend the hydrothermal alteration footprint of economically significant deposits in the Northwest Queensland Mineral Province and aid the aims of the Strategic Resources Exploration Program to expand mineral resource exploration and development. Researchers from CODES are collaborating closely with researchers from CSIRO, sharing sample materials and expertise on mineral assemblages and mineral chemistry.

The Paleo- to Mesoproterozoic Mount Isa district, Northwest Queensland, anchors the Northwest Queensland Mineral Province, one of the preeminent mining districts of the world. Unfortunately, many of the mines of the Mount Isa district are approaching end-of-life scenarios, which could have a significant negative socio-economic impact on the region. Finding new resources and revitalising the Northwest Queensland Mineral Province is therefore of paramount importance.

In 2017, CODES was invited to participate in a new research initiative, the Strategic Resources Exploration Program, which is being led by the Geological Survey of Queensland (Department of Natural Resources and Mines) and the University of Queensland. This research program involves a consortium of researchers from several organisations, including CSIRO and James Cook University, and aims to stimulate exploration and discovery of new resources in the Northwest Queensland Mineral Province. CODES will be a key participant in this collaboration, generating a wealth of new precompetitive mineral chemistry data as we assess whether low-level trace element dispersion halos are encapsulated in distal regions around major sediment-hosted base metal and IOCG deposits in NW Queensland.

Jeff Steadman was appointed as a postdoctoral researcher to this project in mid-2017. A pilot study of pyrite chemistry from the Lady Loretta deposit was initiated as a proof-of-concept study while contract negotiations were finalised. The project is scheduled to get fully underway in 2018, with the appointment of a second postdoctoral researcher, and with Shaun Barker to take on a leadership role for the project once his appointment is finalised in 2018.