Over the last a while this tunnel has been created (see history below).
Current Status: passable by boat (rowboats, sailboats and knarr). Depth will be increased to allow all boats once the ore veins have been mined out.
Cart access is available at points b, c, and d on the map - point a provides access to an underground harbour, and there is currently no western cart entrance (there was once access via the caves on the Winter's Night deed, but that has collapsed and left for anybody that re-deeds that spot).
The bridge inside the cave at the western end is bugged (it has been named to warn people) so do not use it to cross to the footpath.
There are lots of ore veins that still need to be mined out, so there will some weaving to do until these are removed. For those interested in helping mine out the ore there is a map available, see https://docs.google.com/spreadsheets/d/12g02zThs1KFxJc7PhMRqtH3o2qhPnlUY9V41WrVy4Y4/edit?usp=sharing
Those with a long memory might remember this video from the Factional Fight brothers.
Hopefully McGarnicle will stop by and flesh out the early history. When I spoke to him about this project he mentioned that somebody had spent everyday for over a month with an alt army working on the tunnel.
What with burn out, and people relocating deeds in the year since the video, with only part of the tunnel with support beams, it was slowly decaying (not helped by a little bug that saw many tunnels have problems).
Having used this tunnel a number of times, a couple of months ago while using it as a short cut to a rift, the tunnel was blocked in a couple of places due to recent rockfalls. With the help of Gatling and Merina the rockfalls have been removed, together with a few of the ore veins, and the cave walls supported. I have also put some lighting in, to help dispel the Grue and light the way around the ore veins.
Some pictures of the tunnel, taken on a journey west to east.