Yeah you've got me thumbing thru my Derbyshire stuff, from my limited experience the perils of shale I remember well from the loose sections of Cromford Sough on a trip up that... one touch and it fell away.... So how far do you reckon would have to be re-opened in Horizontal terms and what stowed up water risk would there be? Surely this would be a real dangerous dig on a sough. How long is the sough for that matter? Are there full plans any where?
Yatestoop is a pretty lengthy sough - the lower part is very similar to Cromford sough and the blockage is not much further up than the side branch off to the shafts at Millclose. So, there's a lot of sough still to go as it extends almost as far as Winster village, and then links up with other soughs as far as I know (there's an 18th century map of the Alport and Winster mines and soughs, reproduced in Lynn Willies and Harry Parker's book which shows its length). Nellie Kirkham's article on it is also online:
http://www.pdmhs.com/PDFs/From%20PDMHS%20Bulletin%20Vol.%201%20No.%207.pdf In terms of pent-up water, I really don't know what the risk is - the deep shafts at Millclose are suspected to have changed the drainage a lot, and most of the present flow in the sough comes from those shafts. The flow at the run-in doesn't suggest much behind but as it's a shale blockage, that's not a reliable guide to the back-up levels! So, this would certainly be a long-term project for anyone determined enough to try it, given the length and potential for further major blockages. You could say the same about Cromford, Stanton and Stoke soughs too.... 😉
Follow the horses, Johnny my laddie, follow the horses canny lad-oh!