Critical Minerals: How Does it Impact Mine Closure?
Critical Minerals: How Does it Impact Mine Closure?
Critical minerals, sometimes referred to as critical raw materials (CRMs) are defined as materials that are of high importance economically but have high supply risk (European Commission, 2020, p. 1). CRM lists can be the same or change from country to country due to varying industrial needs and applications. For example, in Canada the critical mineral list includes metals and minerals such as copper, nickel, uranium, and zinc (Government of Canada, 2021, par. 3). In Australia, critical minerals include metals and minerals such as cobalt, lithium, manganese, tungsten, and vanadium (Australian Government, 2022, par. 24).
CRMs are a vital component in the creation process of tools people use in their everyday lives. Cobalt and nickel are used in the development of smartphones, laptops, and tablets (Venditti, 2021, par. 5). CRMs like sulfur are widely used in creating household cleaning products and rubber (Royal Society of Chemistry, 2022, par 2).
Not only are CRMs vital to the creation of everyday, household items, but they are also becoming increasingly important in the effort to transition toward low carbon energy.
CRMs Critical to Helping the Energy Transition
Governments across the world have increased their efforts and investment in low carbon energy technologies. For example, renewable electricity generated from systems like wind turbines and solar panels, are expected to increase by 60% from 2020-2026 (IEA, 2021, par. 3).
With increased demand for low carbon energy, there will be an increase in the need for CRMs along with it. CRMs are a key component in the construction and function of low carbon energy technology like wind turbines and solar panels, which both use indium, lithium, and gallium (European Commission, 2020, p. 23) and have been identified as CRMs by the European Commission and the Government of Canada.
As the main industry tasked with uncovering and extracting CRMs, the mining industry will need to increase efficiency of production to accommodate the growing demand for CRMs and help continue the push toward low carbon energy technology. The interest in re-using material from the mining process as a potential source for CRMs is growing rapidly in the industry. This process can also be associated with the concept of a more circular economy.
The circular economy concept is built on the cradle-to-cradle design paradigm introduced by William McDonough and Michael Braungart (ICMM, 2016, p. 6). The cradle-to-cradle design paradigm, at its simplest, creates more value with less impact. A significant feature of the circular economy is identifying opportunities to return biological materials to the earth or to return non-biological materials to the economy (ICMM, 2016, p. 6). Further in their cradle-to-cradle design paradigm, McDonough and Braungart describe technical “nutrients” that drive industrial systems as minerals, metals, and plastics that are more suitable to be recovered, reused, or recycled (ICMM, 2016, p. 6).
There is potential to create a circular economy within the mining industry because of the large volume of residual material leftover from the mining process. Often taking the form of tailings or mined rock stockpile, this material is often stored on mine sites without an identified use past the end of the life of mine.
A circular economy would see material such as tailings and mined rock be, as McDonough and Braungart describe, recovered, reused, and recycled for economic purposes like the extraction of CRMs.
Mine Closure and Critical Minerals
From a mine closure perspective, mine operators could look at incorporating extraction of CRMs from tailings and mined rock into their mine closure planning. Rather than classifying tailings and mined rock as “waste products”, there’s an opportunity for a perspective shift. To start looking at this material as a potential resource, rather than accumulating residual risk in care and maintenance.
With the volume of tailings storage facilities and mine rock stockpiles that has accumulated through mining activities at both legacy mine sites and active mine sites across the world, it’s becoming increasingly plausible they may be a source of valuable CRMs.
For example, residual material from copper mines is found to be a valuable source for CRMs like selenium and tellurium (Alagha, 2021, p. 3). At coal mines, coal ash can produce CRMs like gallium, scandium, and vanadium (Awatey & et. all, 2022, table 1). Coal ash, especially in the United States, is abundant with 129 million tons produced each year (Lasley, 2021, par. 9).
Research being conducted at the College of Earth and Mineral Sciences at Penn State, is identifying a process that can extract critical minerals directly from acid and metalliferous drainage. The process being explored involves collecting acid and metalliferous drainage from ponds and other watersheds and using chemicals to neutralize the pH. This process causes the metals to solidify and can then be collected (Lasley, 2021, par. 49).
Re-mining waste and embracing a circular economy could open doors to opportunities to access CRMs and help the mining industry do our part in helping the world transition to low carbon energy technologies, while lowering our own carbon environmental footprint in the process.
How Okane can Help
We help mining companies integrate closure plans into their life of mine plans to realize progressive reclamation and develop a well-defined, lower residual-risk closure plan. Our team of experienced engineers can help you develop plans to incorporate CRM extraction as an opportunity for potential future returning land use, and help you identify the benefits, risks, and logistics that go into making this a reality. Additionally, the integrated approach we take to mine closure planning can optimize the shaping and construction of landforms after CRM extraction to reduce residual risk, minimize water quality impacts and create a natural looking, sustainable ecosystem long-term.