Rare earth elements

The rare earth elements (REE) are soft, silver-coloured metals that tarnish quickly in air and have high melting points. The REE range in abundance in the crust from about the same level as copper and lead down to the same levels as bismuth. There are many potential REE ore deposits in a wide variety of rocks. The world's largest REE deposit at Bayan Obo, Inner Mongolia, China has produced REE since the late 1980s and currently accounts for the majority of global REE supply. Most REE mines, such as Bayan Obo, Mountain Pass and Mount Weld, are open-cast operations, involving conventional blast, load and haul techniques. REE have a wide variety of applications and, although they are often used in small quantities, they have become pervasive in many technologies, especially those for improving energy efficiency and in digital technologies. Exploration activity for REE has increased greatly in recent years.