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Of about 320,000 known plant species, roughly 700 are known as “superaccumulators”—plants that pull metals such as cobalt, nickel, and zinc out of the soil at high rates.
At a time when demand for metals is rising along with the world’s hunger for more and more electronic appliances, what has come to be called “phytomining” may be crucial for meeting that demand.
In Malaysia’s Kinabalu Park, for example, four acres are planted in a leafy shrub named Phyllanthus rufuschaneyi.
Every few months, local farmers trim off a foot or so of growth from the plants, which can grow to 20 feet in height.
The farmers then burn their harvest, producing an ash known as bio-ore that can produce as much as 25 percent nickel by weight.
The carbon wafting from the burn is far less than what would be produced from traditional mining, with its blasting, excavating, washes of toxic chemicals, and exhaust from diesel trucks hauling raw rock.
The Malaysian nickel field yielded from 170 to 280 pounds of metal per acre, or 150 to 250 kilograms per hectare.
At today’s prices, a farmer “growing nickel” in Malaysia could clear about $3,800 per acre, on a par with other high-yield crops in the region with similar operating costs, according to a study carried out at Australia’s University of Queensland.
In contrast, farmers in the Pacific Islands growing crops for palm oil are netting around $2,710 per acre, the study noted.
Australian scientists are planning a 50-acre trial nickel crop next to gather additional evidence that phytomining is financially practical on a commercial scale.
TRENDPOST: Mining with plants can be economically viable with thin deposits not practical using conventional heavy machines and brute-force methods.
Now that the world is even more aware of the costs of a carbon-heavy economy, phytomining will more easily take root in areas with mineral deposits that are marginal.
Even more important, metal farming will bring a new income stream to subsistence farmers in developing nations.