Looking forward to seeing this :)
and what happens once you get to the far side?
I'm always interested when a small detail such as the anchor hole you mention above seems to tell a story about the place and those who worked there.
And on to one of my favourite topics: wonder what that very hard, hard above the vein actually is geologically - an igneous hardstone of some variety I think, but other than this I don't have any further details.
On a related topic, I often wonder if the workforce actually knew that the "chert" layers were actually compacted volcanic ash (tuff) If they didn't necessarily know in the early days of Cwm/Oakeley, I wonder if this knowledge would have been eventually gained. Maybe all that was of immediate interest was that it was very hard and also brittle and potentially dangerous in the roof ;(
I read somewhere that "Whinstone" was named so, as it made a sound like "whin" when hit, as opposed to softer rocks which make a duller sound. Not sure that this will actually be quite so marked in whinstone surrounded by slate however.
I think the name was imported to Cwm/Oakeley from some other source, possibly up north: The so called Great Whin Sill happens to be made of similar material, to that composing the Cwm/Oakeley dykes: - igneous dolerite.
Anyway, the same argument applies as to weather the workers knew what the stone actually was beyond the fact it was hard, and affected the layout of the chambering when it occurred in dykes. Probably a difficult one to work out without an academic grounding in geology. Anyway perhaps the naming of the Whinstone dykes in Cwm and the Great Whin Sill was a simply a fortunate coincidence - bands and layers of hard stone intruding through other strata being refered to as Whin, and often turning out to be igneous dolerite (and quite possibly other related rocks).
a little :offtopic: (maybe)
'I wonder how many breakfasts, and other meals we have missed inside that nasty clockless, timeless hole?'
'The Hobbit'
J R R Tolkien.