BIOMINING: A NEW WAY TO THE MINE OF TOMORROW

Biotechnology has been developed in the mining sector to help extract valuable minerals and metals in a more efficient and environmentally friendly manner. For example, microorganisms can be used to leach metal from low-grade ore deposits, which can then be extracted and processed. The use of biotechnology in mining is known as biomining.

The first recorded use of microorganisms in the mining industry was in the late 19th century, when bacteria were used to extract copper from ore. However, it was not until the late 20th century that biotechnology began to be widely used in the mining industry. The development of new genetic engineering techniques, such as recombinant DNA technology, in the 1970s and 1980s paved the way for the use of microorganisms in the mining industry. Since then, biotechnology has been used to extract a variety of metals, including copper, gold, silver, and uranium, as well as to clean up contaminated mining sites.

PROCESS OF BIOMINING
Biomining is a process that uses microorganisms to extract valuable metals and minerals from ores or minerals. The microorganisms, typically bacteria or fungi, are used to break down the minerals and extract the valuable metals, such as copper, gold, and uranium. This process is considered more environmentally friendly than traditional mining methods, as it reduces the need for harsh chemicals and high temperatures. Biomining is also used in the production of fertilizers, enzymes, and other products.

The process of biomining typically involves four main steps:
1. Leaching: The ore or mineral is crushed and then treated with microorganisms or their enzymes, which break down the mineral and release the valuable metal into solution.
2. Separation: The metal-rich solution is then separated from the remaining mineral material through a variety of methods, such as filtration, centrifugation, or electrowinning.
3. Recovery: The metal is then recovered from the solution in a form that can be used, such as a metal salt or metal alloy. This step can involve a variety of methods such as precipitation, reduction, or solvent extraction.
4. Regeneration: In some cases, the microorganisms used in the leaching process must be regenerated or replaced. This step is necessary to ensure the continued effectiveness of the biomining process.

It should be noted that biomining process can vary depending on the type of ore, mineral or the type of microorganisms used.

SOME EXAMPLES OF THE USE OF BIOMINING
An example of the use of biomining in a mine is the use of bacteria to extract copper from copper sulfide ores. The bacteria, such as Thiobacillus ferrooxidans and Leptospirillum ferrooxidans, can break down the sulfide minerals in the ore and convert them into soluble sulfates. The resulting copper-rich solution can then be separated from the remaining mineral material and the copper can be recovered through a variety of methods such as electrowinning.

Another example is the use of acidophilic archaea such as Ferroplasma acidarmanus, to extract metals such as iron, nickel and cobalt from lateritic ores. These microorganisms can tolerate high acidity and use sulfuric acid as a source of energy to extract the metals.
Biomining is also being used to extract precious metals such as gold and silver from low-grade ores, tailings and waste materials. In this case, specialised microorganisms such as acidithiobacillus ferrooxidans and acidithiobacillus thiooxidans are used to extract the metals.

ECONOMIC IMPACT OF BIOMINING
The economic impact of biomining can be significant, as it can make the extraction of valuable metals and minerals more efficient and cost-effective. Because biomining uses microorganisms to extract metals, it can be more environmentally friendly than traditional mining methods, which can reduce the costs associated with environmental remediation. Additionally, biomining can also allow for the extraction of metals from low-grade ores and tailings that would not be economically viable using traditional mining methods.

However, biomining is not yet widely used in the mining industry, and the technology is still in the early stages of development. The implementation of biomining can be complex and challenging, and requires significant research and development efforts. There are also still some technical and economic challenges that need to be addressed before biomining can become a widely adopted technology.

It is difficult to provide a specific example of the cost of biomining in a mining process because it can vary greatly depending on the type of ore, mineral, and microorganisms used, as well as the specific mining operations and methods employed. However, I can provide some general information on the costs associated with biomining :
• One of the main costs associated with biomining is the cost of the microorganisms themselves. These can be obtained from commercial suppliers, but the cost can vary depending on the type and quantity of microorganisms required. Additionally, the cost of growing, maintaining, and regenerating the microorganisms can also be significant.
• Another cost associated with biomining is the cost of the equipment and facilities needed to support the biomining process. This can include things like tanks, fermenters, pumps, filters, and electrowinning equipment. The cost of these items can vary depending on the size and type of equipment required.
• There are also costs associated with the research and development of biomining technology. These costs can include things like laboratory research, pilot-scale testing, and the development of new mining methods and equipment.

In terms of traditional mining, biomining process can be more expensive than traditional mining methods, especially in the initial stages. But as the technology matures, costs are expected to decrease and the process may become more cost-effective. Additionally, the benefits of biomining in terms of environmental friendliness and the ability to extract valuable metals from low-grade ores may offset the higher costs in the long run.

It’s important to note that costs are not the only important factor in the decision to use biomining, other factors such as environmental impact, the quality and quantity of the ore and the availability of the microorganisms are also important.

SOCIAL IMPACT OF BIOMINING
The social impact of biomining can be both positive and negative, depending on the specific context and location of the mining operations. Some potential positive impacts include:
• Job creation: Biomining operations can create jobs in the mining, research, and development sectors.
• Economic development: Biomining can contribute to the economic development of local communities by providing a source of income and resources.
• Environmental benefits: Biomining is generally considered to be more environmentally friendly than traditional mining methods, and can reduce the negative impacts of mining on local communities and ecosystems.

However, there are also potential negative impacts to consider, such as:
• Displacement: Biomining operations can displace local communities, particularly those living in areas with valuable mineral deposits.
• Environmental degradation: While biomining is generally considered to be more environmentally friendly than traditional mining, the process can still have negative impacts on local ecosystems and communities if not done responsibly.
• Conflicts: There may be conflicts between mining companies and local communities over access to land and resources.
• Limited benefits: The benefits of biomining may not always reach the local communities that are affected by mining operations.

It’s worth noting that the social impact of biomining can vary greatly depending on the specific context and location of the mining operations, as well as the way in which the mining is conducted. It is essential that mining companies and government organizations work closely with local communities to ensure that the social impacts of biomining are minimized and that the benefits of mining are shared equitably.

IMPLEMENTATION OF BIOMINING IN PHOSPHATE DEPOSITS
Biomining has the potential to make the extraction of phosphate more efficient and environmentally friendly. Microorganisms such as acidithiobacillus, Leptospirillum, and Sulfobacillus1 have been found to be effective in dissolving and extracting phosphates from phosphate ores. The process involves the use of microorganisms to break down the phosphate minerals, releasing the valuable phosphates into solution. The phosphates can then be separated from the remaining mineral material and recovered.
In addition, biomining can also be used to extract phosphates from waste materials such as phosphogypsum2 and animal manure, which would otherwise be discarded, this can help to reduce the environmental impact of mining and also increase the availability of phosphates for agricultural and industrial use.

It’s worth mentioning that research on the application of biomining for phosphate deposits is still ongoing and the technology has not yet been fully developed or commercialized. More research is needed to optimize the process and to overcome any technical and economic challenges that may arise.

CONCLUSION
Biomining has the potential to bring several benefits for the development of new mines:
• Environmental friendliness: Biomining uses microorganisms to extract metals and minerals, which reduces the need for harsh chemicals and high temperatures, thus making the mining process more environmentally friendly.
• Efficient extraction: Biomining can make the extraction of valuable metals and minerals more efficient and cost-effective.
• Low-grade ores: Biomining can allow the extraction of metals and minerals from low-grade ores and tailings that would not be economically viable using traditional mining methods.
• Reduced waste: Biomining can help to reduce the environmental impact of mining by allowing the extraction of metals and minerals from waste materials such as phosphogypsum and animal manure.
• Phosphates extraction: Biomining can also be used to extract phosphates from phosphate deposits, which is a vital nutrient for plants and animals and is used in a wide range of products, including fertilizers, animal feed, and industrial chemicals.
• Job creation: Biomining operations can create jobs in the mining, research, and development sectors.
• Economic development: Biomining can contribute to the economic development of local communities by providing a source of income and resources.

It is important to note that while biomining has a lot of potential benefits, it is still a relatively new technology and more research is needed to fully understand the potential of this process.

References for more details:
• The Biomining website www.biomining.org
• The Biomining Research Group at the University of British Columbia www.biomining.ubc.ca
• The Bioleaching website www.bioleaching.info
• The Biomining Laboratory at the Technical University of Madrid www.biomining.eu
• International Biohydrometallurgy Symposium (IBHS) www.ibhs.info
• « Biomining: Theory, Microbes and Industrial Processes » by R.N. Reeve and J.B. Neilands
• « Microbial mining of minerals » by J. Brierley and C. Brierley – published in the journal Nature Reviews Microbiology.
• « Biomining: Metal Recovery from Ores with Microorganisms » by A. Kappler and W. Schühle, published in the journal Applied Microbiology and Biotechnology
• « Biomining: An Introduction » by C.J. Mitchell and M.B. Roberts, published in the journal Biotechnology Advances.
• « Biomining: a review of microorganisms and their role in mining » by A.L. Moreira, L.F. de Oliveira, published in the Journal of Applied Microbiology.

Youssef Daafi
Geologist Expert: CPG-AIPG, EurGeol-EFG, QP-MMSA, RM-SME & PEV-ABET