Phytomining—Spinning Hay into Gold!

Imagine mining farmland for nickel, cobalt, and other profitable metals with a simple crop of hay! It’s called phytomining, and a newly patented process created by the Agricultural Research Service and Viridian Resources, L.L.C., of Houston, Texas, shows that it is commercially feasible.

Utilizing certain plant species that hyperaccumulate nickel from contaminated soils, ARS agronomist Rufus Chaney, working with Scott Angle (University of Maryland), Alan J.M. Baker (University of Sheffield), Yin Li (Viridian), and Richard Roseberg (Oregon State University), developed an environmentally friendly alternative to traditional mining techniques. The group targeted a number of plant species that recover unusually high amounts of metals through their roots, evaluating several hundred strains for favorable genetic characteristics. The crop they developed is ultimately burned after harvest to create an energy byproduct, the remaining ash being the source of the metal.

Phytomining on contaminated soils is reportedly more lucrative than growing traditional crops on the same land. Harvests from low-grade pastures or forests grown on such land would fetch about $50 to $100 per hectare per year. But a phytomining crop growing on the same land would produce an annual 400 kilograms of nickel per hectare worth more than $2,000 even at today’s depressed market price for nickel. After selling the byproduct energy, the annual per-hectare value of a phytomining crop exceeds $3,000!

Phytomining is expected to enable the tapping of vast mineral deposits throughout the United States which were otherwise unavailable through conventional mining techniques.