This is how I described what I found in the upper breakdown chamber for the PDMHS newsletter:
The floor of the upper breakdown chamber consists of large boulders that have fallen from the roof and jammed together to form a floor, though in a number of places voids can be seen through the gaps between these. The most stable-looking of these was descended to a depth of 10m, the boulder layer being about 3m deep. This was at a point where two parallel stopes had been connected by the miners. The initials “HSS” had been smoked onto a rider between the stopes, showing that this area had been visited by explorers or spar miners before; if any members can suggest who this is/was or likely dates for this then please speak up
To the west, the northernmost stope ended after 7m at a packwall with a single stone stemple wedged across the stope just in front of it, a higher continuation above this was choked with boulders after a short distance. To the east, collapse debris blocks the way after 3m though a choked cross-cut or thurl can be seen; there is evidence of firesetting in the form of smoke trails and fragments of burnt coal and heat-affected limestone
The southern stope is narrower; to the west a steep rubble slope heads up to another of the holes in the breakdown chamber floor but due to an unstable section, no attempt was made to exit this way. There is a short scramble up another rubble slope to the east, then it descends steeply for about 7m with a 2m drop midway along it. A small hole could be seen at the base of this slope; this was not investigated at the time but may lead to further workings if pushed.