Q&A Series #28: Interview with Homayoun Fathollahzadeh

The topic of discussion: Circular economy strategies for biomining of metals. 

New low-carbon and renewable energy resources are demanding metals and minerals in an exponential way. However, the extraction of these critical minerals such as copper, cobalt, nickel, and rare earth elements is becoming energy demanding and difficult every year. 

Biomining is the use of microorganisms to extract and recover valuable metals from minerals and wastes and has been employed on Earth for several decades.

Since the discovery of the role of microorganisms in rock-weathering processes in mid-1900s, microbes have been intentionally utilized for biomining metals from terrestrial ore deposits. 

Currently on Earth, around 20-25% of copper and 5% of gold are extracted using biomining. It provides economic and environmental advantages to other methods and can be used as a complementary technique to extract trace metals from mine waste. 

Applications of biomining include but are not limited to:

• Leaching of copper, nickel, cobalt, zinc, and uranium
• Pre-treatment of refractory sulfidic gold ores and concentrates 
• Recovery of metals from electronic waste 
• Recovery of metals from regolith 
• Selective extraction of space resources 
• Production of high-quality metal concentrate 

Global Road Technology discusses circular economy strategies for biomining of metals with Homayoun Fathollahzadeh, a Critical Minerals Biohydrometallurgist based in Perth, Western Australia.

1. Can you take us through your role as Homayoun the Critical Minerals Biohydrometallurgist? What does that entail and how important is what you do to the circular economy in the mining industry?

As a Critical Minerals Biohydrometallurgist, my main aim is to advance microbial and geochemical functionality for mining practices. With increasing environmental degradation, water, and mineral scarcity, as well as high demand for critical minerals like Rare Earth Elements (REEs) and battery metals (Li, Ni, and Co) there has never been a better time for the use of biomining. 

Biomining has clear advantages over conventional and existing processes including simplicity, lower capital/operation costs, and reduced environmental risks. It involves bioprospecting, molecular microbiology, characterization, studying the potential of single and/or a group of microorganisms for use in bioleaching as well as understanding mineralogy, geochemistry, modelling, and extractive metallurgy. This role is quite unique and diverse. So as bio-miner, my role is pursuing green technologies to drive environmentally friendly and successful delivery of sustainable development goals (SDGs) for the global heavy metal and mining industries.

In terms of circular economy, unlike pre-existing hydrometallurgical techniques, biomining promotes resource efficiency and unlocks the full potential from both primary (high-grade ores) and secondary (low-grade ores, tailing, and waste residues) resources. Utilising biomining as a biohydrometallurgist means exploring a diverse range of opportunities – from exploration to down-stream processing as well as mine closure and reclamation. This valorisation develops smart strategies to reduce carbon footprints and manage carbon more efficiently.

2. How important is Research and Development in unlocking mysteries of the natural and engineered ecosystems?

Research and Development is critical to unlocking the mysteries of both natural and engineered ecosystems. Only by addressing critical knowledge gaps through research and development programs can we develop proactive solutions for the global heavy and mining industries. To create a healthy environment within both natural and engineered resource ecosystems, current operation practices for both closed and active mine sites need to change dramatically so that they are reflecting environmental liabilities, not only corporate risks. The only way that this is possible is if an effective Research and Development program is employed.

3. What role can microbiology play in the recycling of critical minerals? Can it work in isolation? If not, what other technologies can add more value to the process of recycling?

Due to the complexity and heterogeneous characteristics of waste materials, recycling of critical minerals is challenging. However, microbiology, or more specifically, the use of suitable microorganisms can play a critical role in the recycling of critical minerals. This is due to the catalytic role of some microorganisms in the bioleaching of valuable metals from various metal-containing substrates such as ores and electronic waste. While microbiology alone can achieve a critical portion of the actual reactions required for the recycling of critical minerals, inclusion of other technological sciences, such as Biotechnology, Bioinformatics and Synthetic Biology can help to industrialise and revolutionise the action of the microorganisms so that they are performing at an enhanced level. More specifically, using Bioinformatics to identify the key mechanisms (genes, proteins) used by the microorganisms in the recycling steps can lead to the either the tailoring of the microorganisms (synthetic biology) or the industrial conditions (industrial biotechnology) for maximum recycling efficiency.

4. Typically, what goes into the life cycle assessment (LCA) of mining and mineral processing? What is being done to deviate from linearity to circularity?

Life Cycle Assessments (LCAs) are a great tool to avoid claims of greenwashing during mining and mineral processing, if done correctly. However, results vary with the quality of input data and assumptions. System boundary within LCAs studies normally includes data on emissions, energy, materials, and processes. There has not been much work done on complementing the circular economy with LCA within mining industry. The main reason for this could be, as for example, the value chains of REEs is complex, includes many variables, inputs, players, and collecting related data inventory is challenging. However, we can begin to develop standards and guidelines to improve integrity across the value chain and help deviate from linearity to circularity.

5. What challenges are faced in application of synthetic biology across the entire mining supply chain including exploration and sensing, in-situ extraction, leaching, beneficiation, remediation, and recycling?

Classic synthetic biology mainly was developed by research around E. coli bacteria which paved the way to the scientific innovation on so-called “designer” bacteria. However, such bacteria do not have tools to fully operate in mining conditions. On the other hand, out-side the lab in mining ecosystems there is a wide range of challenges such as extreme conditions (e.g., temperature, pH, and radiation) that can slow down the leaching process that we are after. Moreover, unfortunately, the application of advanced sequencing technologies within “World class research institutes” have been misused and more focused on making a bigger list of microbes in tree of life rather than a better understanding on function of existing microbial community, for an example in a mining leachates and what they can offer to solve daily problems mining companies encounter. Nevertheless, the potential technology and market for engineered microbes, where they can use carbon dioxide as a feedstock for production of carbon negative processes, is enormous and holding great promise for addressing mining carbon footprints. As bio-mining and biotech ambassador, I am hoping sooner than later, we build dialogues and focus on establish activities toward communities, stakeholders, corporates, and scientists.

6. How would you address the question of sustainability in the context of carbon-negative mining?

In my opinion, it is only a matter of time until we reach sustainability in carbon-negative mining. To be successful, any carbon-negative solution should be functionally stable in the long term. Like carbon farming in agriculture where soil, water, animal, and vegetation are embedded well within management and operation platforms, in the mining industry, good mining practices should be defined as community, land, water, energy, and resources are valued properly. I believe initiatives such as the Australian Carbon Credit Units (ACCUs) could improve mining commitments towards a sustainable future.

7. 20% of the world’s copper is extracted through bioleaching. How can we enhance this natural method of mining? In the future, what can be done to harness more from natural methods of mining?

There is a high degree of functional and genetic diversity among characterized microbial communities within bioleaching systems. Due to the innate potential of bioleaching bacteria to produce an array of metabolites, studying microbial black boxes through molecular genetics and bacteria-mineral interactions will play a vital role in understanding the mobilisation mechanisms of metals and, therefore, enhancing bioleaching efficiency. Further bioprospecting from extreme environments for the characterisation of novel indigenous microorganisms could also allow for the isolation and selection of highly stress-resistant biomining microbes with the ability to leach metals under extreme biomining conditions. This would ultimately increase bioleaching efficiency. Furthermore, further studies of the accumulation and regulation of ligands during the solubilisation process is essential to enhance the functioning of these microorganisms for the efficient leaching from minerals.