The extraction of metals from the earth is an ancient process, but also one that has seen numerous improvements in the most recent two centuries.But virtually all of the elemental metals that have been discovered in the past 300 years have been found either alloyed with another element or elements, or have been found as some kind of ore, often an oxide or sulfide ore or both.The techniques used to separate metals from such ores have become very well-established, mature processes, and none are considered dependent on any biotechnological steps.