I've not done the trip to the end of the 'temple of doom' extensions, but it is in Mike Cooper's "Not for the faint-hearted" guide, and so I assume it is still open...
Its a place I hope to visit soon!
There is a website for Mike's book - www.notforthefaint-hearted.co.uk - where it is possible to find up-to-date info on the trips in his guide (as long as people keep giving him feedback anyway).