Copper occurs in nature mixed with other minerals and valuable metals in ore, and the proportion of copper in the ore can vary considerably. Until fairly recently, the only way to extract pure copper from ore was by using a process that requires large amounts of electric energy, especially if the proportion of copper in the ore is low. New copper-extracting technologies can use up to 40 percent less electricity than the older method to process the same amount of raw ore, especially when the proportion of copper in the ore is high. Therefore, we can expect the amount of electricity used by the copper-extraction industry to decline significantly.