My interests now include new areas on the east bank. As long as the promised storms aren't too bad I'll be up at Pen Ffordd Goch tomorrow on a 400 mile day trip looking at surface landforms, maybe I should take a couple of bent coat hangers with me to help me solve a "Mystery"
For what it is worth I do think Lasgarn Quarry Cave is part of the bigger system, although maybe now isolated by erosion. There was a distinct cool draught coming out of it last June and July, hinting that there is some further passage still connected to it. Incidentally, a number of sites south east of Blaenavon had begun sucking in air a few weeks ago.
Graigwen - The last time I was at Jackdaw Quarry Cave, it was draughting inwards too. I sprayed canned smoke in the final dig/crawl to the shaft, back out towards the entrance and it reversed quickly, blew through the crawl but went up the shaft, into the boulders above towards the surface, not down the shaft, even though there was water falling.