Via the Telegraph:

A draft report by China’s Ministry of Industry and Information Technology has
called for a total ban on foreign shipments of terbium, dysprosium, yttrium,
thulium, and lutetium. Other metals such as neodymium, europium, cerium, and
lanthanum will be restricted to a combined export quota of 35,000 tonnes a
year, far below global needs…..

Mr Stephens said China had put global competitors out of business in the early
1990s by flooding the market, leading to the closure of the biggest US rare
earth mine at Mountain Pass in California – now being revived by Molycorp
Minerals.

New technologies have since increased the value and strategic importance of
these metals, but it will take years for fresh supply to come on stream from
deposits in Australia, North America, and South Africa. The rare earth
family are hard to find, and harder to extract….

USGS fact sheet 087-02: “Rare Earth Elements—Critical Resources for High Technology