Mining critical minerals
Some critical minerals—such as copper, zinc, and aluminium—have been mined in Queensland for decades but are being used in new and different applications to help emerging technologies and contribute to decarbonisation. However, quite a few minerals are about to be mined for the first time. That’s why the exploration of critical minerals is crucial to help unearth new and deeper reserves and deposits.
We know there are deposits of critical minerals in a broad corridor from Mount Isa to Townsville and we are currently exploring these areas through numerous initiatives. Many critical minerals are located alongside traditional commodities so we are focusing on the following 2 areas to locate and utilise these minerals:
New exploration activities
Exploration activities, such as geophysical surveys, help us discover new deposits of minerals. The following projects involve searching for minerals as well as looking at ways in which we can sustainably extract them.
Kamilaroi airborne magnetic survey
Geological Survey of Queensland (GSQ) is undertaking an airborne magnetic survey north of Mount Isa, following the known trend of cobalt mineralisation associated with major copper deposits. This survey will better define key structures known to be responsible for this style of mineralisation. The survey has the potential to open exploration for copper and cobalt in previously under-explored areas.
What is it?
An airborne magnetic survey is where either an aeroplane or helicopter with a magnetometer attached does a geological map over large areas—it’s one of the most rapid and efficient methods of doing magnetic surveys. The magnetometer measures the total intensity of the Earth's magnetic field along continuous flight lines at a fixed distance apart. The aircraft is flown at a constant terrain clearance, with modern surveys flown at less than 100 metres above ground level.
Canobie gravity gradiometry survey
GSQ will undertake a high-resolution gravity gradiometry survey north of Cloncurry, including the Saxby area, to assist with targeting critical mineral and iron-oxide-copper-gold deposits (IOCG). In addition to being a major source of copper in the North West, IOCG deposits are a key host to other critical minerals such as cobalt and rare earth elements.
What is it?
Gravity gradiometry is the study and measurement of variations in the Earth’s gravity field. For mineral exploration, it measures the density of the subsurface to gain information on geologic structures underground and undersea. Or simply put, it helps us understand and see beneath large expanses of covered rocks and reveal our potential resource deposits. Gravity gradiometry enables us to efficiently target exploratory activities and minimises surface and community disturbance.
Carpentaria Conductivity Anomaly magnetotelluric survey
GSQ is undertaking 2 broad-scale magnetotelluric (MT) surveys to the south and east of Cloncurry to map out the Carpentaria Conductivity Anomaly, a geological feature that may be prospective for copper, cobalt and rare earth elements.
What is it?
Magnetotelluric surveys are used to reconstruct the underground resistivity disruption from shallow depths to hundreds of kilometres depth. It uses natural time variations of the Earth’s magnetic and electric fields to measure the subsurface. Electrical resistivity of rocks and minerals is an important physical property to measure to understand geological structure and processes.
Extracting rare earth elements sustainably
This initiative is crucial to the future development of an entire rare earth elements (REE) supply chain. By demonstrating an economic and environmentally sustainable extraction method for REE, numerous exploration-stage REE projects will become viable.
Commercialising these techniques will create new jobs in and around a Queensland-based processing facility, with flow-on benefits for communities and the region.
Determining the rare earth element potential of Queensland’s basins
Researchers at Adelaide University have developed a cutting-edge model for rare earth mineralisation in basin environments. GSQ will conduct a project in collaboration with Adelaide University to develop this model further with particular reference to specific examples and regions in North West Queensland, such as the Georgina Basin around Mount Isa. This model will enable explorers to identify prospective target areas more effectively.
Collaborative Exploration Initiative
The Collaborative Exploration Initiative (CEI) supports innovative mineral exploration by providing grants to companies undertaking higher-risk exploration activities, or activities in previously under-explored areas of Queensland.
Re-examining existing mines
We are always looking at ways to sustainably re-use old mines. In our search for critical minerals, we are analysing waste from existing mines, and looking at old mines to see if they contain viable deposits.
Analysing mine waste materials and core samples
In collaboration with the Sustainable Minerals Institute at the University of Queensland, the GSQ is re-analysing samples from mine waste materials at mine sites throughout Queensland to identify critical mineral opportunities.
In the past, cost constraints prevented many companies from analysing drill core samples beyond a restricted suite of metals when conducting their exploration programs. For example, a copper explorer might typically examine the core only for copper, lead, zinc and possibly gold and silver. Cobalt—which may be associated with copper—was not commonly included in those examinations.
GSQ is re-analysing large volumes of core samples obtained from known deposits. GSQ has access to many drill core and surface samples through its drill core libraries, as well as through collaborative relationships with key Queensland explorers. This information will be digitised and released to the public.
Reusing old mines
Several previously mined sites in Queensland have returned to state control and may contain untapped opportunities. These sites are ideal for exploration as they are on existing mining leases, infrastructure (in some cases) already exists, and the resources are above ground. In collaboration with the University of Queensland, we are examining the potential of mine waste for critical minerals and finding opportunities for further development.
What is it?
Mine waste comes from extracting and processing mineral resources. It can include things like:
- tailings–the waste material left over after the valuable component has been removed through processing
- stockpiles–piles or storage locations for materials or product which has been extracted through the mining process
- waste dumps–usually the most visually obvious landforms left after open pit mining. The dump’s height and slope angles need to be designed to ensure the final landform is safe, stable, and not prone to erosion.
Some of this waste is unlikely to damage the environment, however, some waste can contain large quantities of substances like heavy metals. Properly managing mining waste will prevent or minimise water and soil pollution arising from acid or alkaline drainage and the leaching of heavy metals.
If critical minerals are found, sites could be re-packaged and offered back to the market, perhaps with incentives or collaborative arrangements to address any legacy environmental issues.
More information
If you’re looking for more information about exploration activities or geological surveys, email gsq@resources.qld.gov.au
Last reviewed: 28 March 2023