Critical minerals are found in primary deposits across the world, and as byproducts of other mining activities.
How are critical mineral deposits found?
Generally, critical mineral deposits are found by geologists working from survey data, which is the geological mapping of a region. In Canada, the Geological Survey of Canada is responsible for surveying the land to determine the type and formation of deposits in various regions; this information is then made public for geologists and other professionals to use in their work to confirm the presence and viability of mineral deposits. Having complete surveys of many regions is important to minimize the impacts of exploration activities on land and communities.
When data indicates the presence of a deposit, its viability can be confirmed in a number of ways, including geochemical sampling and drilling. At this stage, exploration geologists visit deposit sites and are generally working form basic, temporary camps, with minimal disruption to the local environment. This fieldwork is the first step to building a mine, but it does not guarantee that development.
Where are the critical minerals in Canada?
Critical minerals are all over Canada—in fact, it’s likely many deposits have yet to be discovered! To date, Natural Resources Canada (NRCan) has developed a map of critical minerals projects in Canada
, including advanced projects, mines, and processing facilities, with an option to simultaneously show the geology of the region.
The Geological Survey of Canada, the United States Geological Survey, and Geoscience Australia have also developed a collaborative map of critical minerals across the world
, with an accompanying legend
How are mineral byproducts recovered?
After minerals are extracted from the earth, they are processed to recover the mineral of interest. This portion is called the concentrate, which is further refined to generate a saleable product, while the remaining material becomes waste, called tailings. Some processing plants are built with the intention of recovering minerals beyond the primary mineral in the deposit: this is common for cobalt, for example, a critical mineral often produced as a byproduct of nickel or copper. In fact, up to 90% of the cobalt produced in 2021 was as a byproduct.
In such cases, the tailings from the primary concentrate are worked through a secondary processing circuit, which generates a second concentrate stream and a final tailings stream. While this stream may be processed again for other trace minerals, it is generally discarded in tailings ponds outside the plant. Meanwhile, the concentrate stream can be sold to manufacturers for use in consumer goods.
Several critical minerals are commonly found as byproducts of other valuable minerals, but in many cases, the mining and processing facilities for these deposits were developed before the criticality of these minerals was identified. This means that rather than being processed to generate value and increase supply of critical minerals, these key materials are sent to the mining equivalent of a landfill—however, as awareness of and demand for critical minerals increases, new ways of recovering these streams are being developed.
One way to recover critical mineral byproducts is to retrofit a plant to incorporate a secondary processing stream. This method has multiple advantages: not only does it increase the value of saleable product being generated by a mine, but the Canadian government also supports such expansions as critical mineral development projects.
The disadvantage of retrofitting a plant to process secondary minerals is that this method cannot account for the value discarded in tailings prior to the retrofit. Many researchers are currently developing the possibility of “re-mining” tailings, where waste deposits would be characterized by geologists to identify potential value streams, then re-processed to recover those minerals. While there are limits to this approach, largely due to the safety risks associated with working with tailings—which often have the consistency of quicksand, unlike the hard rocks found in most primary deposits—it is a highly promising field of research. Re-mining tailings would mitigate the risk of critical mineral shortages while providing significant environmental benefits, like the rehabilitation of orphaned or historical mines.
Are there other sources of critical minerals?
Many critical minerals deposits have yet to be found, and as geologists begin focusing on this sector, it is likely that new discoveries are imminent. Public geoscience, like the surveying of land by associations like the Geological Survey of Canada, is essential to facilitate these future discoveries. With more data like this at their disposal, geologists and explorers will be able to identify deposits while minimizing disturbance to communities and ecosystems.
In addition to mining, recycling will be an essential source of critical minerals in the future, as their deposits are finite. Many of the minerals currently in our phones, cars and laptops could be re-used for other applications if they could be efficiently and effectively separated from other components. While recycling technology requires further research and development to reach this point, many researchers believe that developing the “urban mine” of consumer goods is essential to maintain the supply of critical minerals for future generations.