I heard about the possibility of this earlier this year and have come to the conclusion that there are nothing like 60 aircraft involved. I don't see the logic of burying huge loads of what at the time were modern aircraft and were sill in service with The R.A.F for a further 10 years. Until I see some more evidence I remain unconvinced . It reminds me of a rumour that was around in the late 60's that British Rail had mothballed around 20 steam locos, shunted them into a tunnel on a disused line in South Wales, then sealed it off.
However if it is true then I'll be delighted to see some Spitfires returning to flight status, I think there are only 3 or 4 airworthy examples nowadays.
EDIT, O.K, I got the location wrong but here is the story
http://semaphoresignals.blogspot.co.uk/2006/01/strategic-steam-reserve.html
Pete