Low-grade ore

A low-grade ore contains only a small proportion of copper compounds. Extracting copper from it by traditional mining may require enormous quantities of rock to be dug up, transported and disposed of for a relatively small yield of copper. This can disturb habitats and landscapes and may require substantial energy.

The two methods required here are phytoextraction, which uses plants, and bacterial extraction, commonly called bioleaching. They can make low-grade ores, mine waste or contaminated soils useful, but both are generally slow. They are therefore alternatives for suitable circumstances, not automatic replacements for every conventional method.

A low-grade ore contains only a small amount of copper compound, so extracting copper by conventional methods may be less worthwhile. Biological methods offer ways to recover copper from such material. They use bacteria or plants to collect copper compounds, but neither method produces copper metal immediately.

As richer deposits are used, it becomes increasingly useful to recover metals from low-grade ores, which contain only a small proportion of the desired metal compound. Conventional extraction from such material can require extensive mining and substantial energy for moving, heating and processing large quantities of rock.