A bit of detective work by Don last night who has concluded that this in fact is a bridge that was removed rather than a bridge that was never completed.
The level is in fact walled up and from below and backfilled, so it looks like the bridge was removed and the support pushed out of the way when it was no longer needed.
Photograph:
🔗Cwmorthin-Slate-Mine-User-Album-Image-94215[linkphoto]Cwmorthin-Slate-Mine-User-Album-Image-94215[/linkphoto][/link]
my orders are to sit here and watch the world go by