Experts forecast global demand for nickel will rise from 2.39 to 2.67 million tonnes in just one year. That’s almost 12% growth for 2021. Today, we rely heavily on traditional mining exploration to meet demands. But many of our primary sources are being depleted and the demand means the industry needs to develop secondary resources such as recycling urban waste, reusing lower quality ore, and harnessing mine tailings. While many approaches are being considered, one that’s caught our attention for its kind environmental treatment is farming minerals via agromining and phytomining.
Money growing on trees.
Imagine a world where the quality of trees growing could determine the quantity of nickel ore collected. Sounds bizarre yet intriguing. Ok so how does it work? The idea features nickel-rich soil and special plants. Although metals have toxic components for plants, they can absorb metals through their roots and store them in their leaves, fruits or flowers. The process is called hyperaccumulation.
Investing in under-used land.
What is the difference between agromining and phytomining? The type of land used. Agromining takes place on low-productivity agricultural soils, while phytomining takes place on degraded or previously mined land. The latter is about planting in areas with mining wastes that contain a large number of untapped resources. Not only is this creating a circular economy and boosting raw material supplies, the phytomining process assists in cleaning soils from toxic metals. Redeveloping waste sites and making them viable for future agronomic use is a serious win for the planet.
Mining without digging.
Both plant-based mining approaches require less chemicals and produce less waste than traditional mining via digging. Farming metal relies on combustion because plants burn, but metal does not. Once plants are cropped and burnt, energy and ashes are produced. Those ashes yield bio-ore, which can have remarkable purity. This makes these metals suitable for applications like rechargeable batteries.
Real case scenarios.
Researchers from the INRAE (France's new National Research Institute for Agriculture, Food and Environment) state that agromining makes it possible to extract up to 100 kg of nickel per hectare of Alyssum murale crop in Albania. Several phytomining and agromining trials are underway in Malaysia, Indonesia, New Caledonia, Zambia, and other countries to identify new hyperaccumulator plants and evaluate their suitability for harvesting nickel. The research helps to align the right species with the right environment and metal to produce the best outcome.
Plants verses trees.
Just like all good things, growing trees takes time. Once a forest is produced, annual harvests could be conducted in an ideal scenario. This is a great alternative to harvesting smaller plants that can require using the majority of the plant, requiring a lengthy regrowth phase. Balancing crop growth and harvesting can be tricky, so incorporating larger crops like trees that remain intact and produce annual yields is a great combination. However, we need to stimulate biomass production and nickel yield to identify the best approach for trees.
The economic viability.
With only 15 years of research, we’re still in the infancy phases. Many technical and economic factors must be considered. Some costs still need to be estimated like building and maintenance costs for processing facilities and global infrastructure. And we need to learn how to grow the best plants during the right phases for them to absorb the highest concentrations of metal. As well as the optimal fertilisation treatment that compensates for deficits in the soil.
Giving back to the land.
Phytomining has been approved as a viable option to complete rehabilitation on mining soils. Rehabilitation efforts are underway in the Asia-Pacific region following the strip-mining of nickel. In New Caledonia, native hyperaccumulator plants are being planted to restore soil health and produce additional supply. The emergence of plant-based mining techniques provides an additional mining source and a new field to develop.
Transition to cleaner energy requires intense innovation. Agromining and phytomining are great examples of radical innovation to long-standing traditional mining practices. We are living in a world of rapid change and the shift towards sustainability is gaining serious momentum. All industries are finding ways to participate and advance the cause. And that’s a great thing because the world is ready and the planet can’t wait.
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