Yes thats exactly it , was rocks to the roof mixed with barb wire , Very noticeable cold water coming into the mine as it was snowing on that trip when we sat in the western shaft for lunch .
I believe the Shallow adit was underneath the engine house itself , looking towards the puddle pit"stood in car park" , there is a fence on the slope to the left , maybe the tubs came up and out here also ??
still no clearer to what the old shafts in the field exactly was ? possibly a different cyffty venture "old"