The caverns are shown on the A.D. abandonment plans, they look both extensive and interesting.
We dug the falls in Barras End low level when I first became interested in this mining area, some 50 years ago!
Subsequently Earby, had another dig in there but abandoned it.
I last looked in there, about 10 years ago, and came to the conclusion that I did at the time, a shaft or stope has run, filling the final terminal fall with lots of fines. It would be difficult to dig this one.
I have always thought that a better bet, would be to dig out reformer level, which is above Barras End and should access the same ground at a higher level. Once you get in here the way to the cavern would be a lot shorter!