Current issues for future access at Trewavas are being negotiated between National Trust & Carn Brea Mining Society, even if these are sorted out there are ecolgical problems (well known locally but can't be advertised) which would result in a close season. We did a detailed survey of most workings some years ago, apart from the obvious there are some very obscure workings only accessible in calm seas & some we need to investigate further. Hope to publish these eventually. There is some doubt about the long term security of the seaward side of the western engine shaft, CBMS have been discussing with NT about doing a detailed survey of this shaft. As stated the sea has broken in to the shaft around high water mark.
The much quoted reports about the sea breaking in and closing the mine seem to have been a rumour in London designed to push down share prices, in fact the mine closed because of heavy financial losses - like just about every other mine.