Thanks, Barewirewalker.
I'll keep a note of that ravine for future walks in the area.
My heartfelt thanks for this topic and a happy reminder of this ravine. Mrs BWW and I returned there yesterday and did a glorious 6.25 mile circular culminating in Foel Fadian as the sunset started over a distant view of the sea.
By re doing the section up the ravine I have had to re-assess my ideas of the purpose of the apparent track I originally took. Those who walk Glyndwrs Way are actually within yards of this glorious spectacle, yet it is hidden from view by nature of the convex slope at the top of the ravine. I had originally thought that the track I had followed was an old miners way into ravine, even perhaps a tramway, but I now have a different idea. It would not be wise for an inexperience walker to do this route as it has fallen into greater disrepair since my previous visit and now two fences cut across it so it is not the right of way. Once in the ravine there is a clear way carved out of the hillside, like a hanging terrace in places but in two places it comes to an abrupt end and in potentially dangerous circumstances. However a close attention how the sheep use the old way and make their own variations can give a clue how to safely avoid the dangers left by miners of old.
This old way is I believe the course of an elevated water course to bring a source of water to the mine crushing plant, as Iron stanchions embedded into the rock seem to indicate supporting a structure that is no loner there. If a visitor can find the eye of a needle then they are not far from where this way seems to originate with ironwork embedded in the rock of the river bed.
The scenic value of the place is very poorly represented at this time because the southern side of the ravine has recently been cleared in the usually untidy way of forestry harvest. Were the natural habitat allowed to re-establish this could be a magical place, and the highlight of many a route.
The Eye of the Needle is along side a narrow cleft that seems to earn the name of the Miner's Gate if you choose to find it and walk through it. It the approach would be tricky, but the sheep do it and a view of it's potential is only a few yards from Glyndwr's Way.
As an afterthought;
The Eye of the Needle and The Miner's Gate are in Open Access though this seems to come to an end half way down the ravine. However a RoW crosses the ravine 1/3 of a mile from the end of OA. Happy trespassing.