Found reference to it in "Goldscope & The Mines of the Derwent Fells" Ian Tyler 2005 , pages 237 - 240.
He refers to it as "The Rachel Wood Crosscut". He mentions that sump & refers to it as "The main shaft". Reading a bit between the lines, it appears to be 10 fms. below adit, but the text is rather ambiguous.
Gating was done by Forestry Commission.
edit
There's a photo on p220 that confirms it as "Engine Shaft" 200yrd's inbye of portal. There's also a mine section on p218 that shows it as "Engine Shaft May 1905, 10fms".
Hope this helps.
Nigel
We inhabit an island made of coal, surrounded by a sea full of fish. How can we go wrong.......