The Future of Mining?
A new mining technique being developed in Australia could one day end the environmentally destructive mining process. The technique is based on the practice of phytoextraction, which is the process by which a plant removes specific elements from soil and stores them in the plant structure. Phytoextraction is used for hazardous waste soil cleanup to remove heavy metals, however the Australian process is one of the first commercial uses studied as a means to extract valuable metals with plants.
Certain types of plants are being bred in a hydroponics setup, and the researchers are working on developing plants within a few months that can take up as much as 5% of their dry weight as gold. The process, termed Phytomining, uses types of plants called hyperaccumulators, which have a tendency to uptake more metals than other plants. For example, one variety of the African shrub Haumaniastrum has a tendency to accumulate copper in comparatively large amounts. The phytomining technique involves planting large numbers of hyperaccumulating plants in ore-rich soil, and then harvesting the plants to recover the metal. The plants would be burned as biomass, which provides valuable carbon-neutral heat energy, and then the ore is smelted out of the plant ash.
A mine of the future might be industinguishable from a natural field or grassland, and could be completely benign, quiet and safe.
Gold farming a growing concern – Sydney Morning Herald