I thought the roadside one was a fluorspar trial, but I don't know where I got that from. It goes fairly shortly to a blind forehead. Somewhere I have a photo of it.
Duck Steet Quarry seems to be some sort of butterfly sanctuary, and might even be owned by a group of interested parties.
Edit: afer a quick search this is the inside near the end:
🔗Personal-Album-2571-Image-90655[linkphoto]Personal-Album-2571-Image-90655[/linkphoto][/link]
and another of the outside, which suddenly looks a lot larger with a person added!
🔗Personal-Album-2571-Image-90658[linkphoto]Personal-Album-2571-Image-90658[/linkphoto][/link]