The cancellation comes amid speculation that China could cut off supplies of the rare earths metals.

Malaysia's environment ministry set conditions in December for Lynas to remove its waste stockpiles before it would renew its operating licence.

Burundi's mining sector was thrust into prominence last month when the US said it was one of those it was considering to diversify its sources of rare earths.

Precision Periodic says its Thor filter could be a game-changer for US production of its own rare earth elements supply.

Malaysia's energy and environment ministry had set conditions in December for Lynas to remove its waste stockpiles before it would renew its licence.

Trump invoked the 69-year-old Defense Production Act -- once used to preserve American steelmaking capacity -- to remedy what he called “a shortfall” in production of the super-strong magnets made with neodymium and samarium.

The East Kootenay coal deposits and coal tailings facilities may contain some of the 17 metals that are critical for everyday electronic components.

The Pentagon wants miners to describe plans to develop U.S. rare earths mines and processing facilities, and asked manufacturers to detail their needs for the minerals.