Re: Rare Earth Elements
'However if they get really short there are millions of tons of spoil heaps in Cornwall just waiting to be mined!'
Perhaps not too far-fetched - although bloody Prince Charles and the National Trust who own most of Cornwall between them would probably block it.
Quite recently, sizeable amounts of indium* have been identified in ores from South Crofty (the last mine to work in Cornwall), and across the pasty wall the Hemerdon Mine near Plympton is about to start producing large quantities of tungsten. I wouldn't be too surprised if some of the Cornish tips were also valuable sources of wolframite which was mined alongside tin in the 19th Century, but thrown away as being valueless and for making cassiterite hard to smelt.
*okay not a rare earth, but very, very necessary in touch screen displays.