If you like your adits and industrial archaeology, here's a free, very visual write-up for you about the mile-long Penrhyn quarry drainage adit, built 1847-1849, possibly involving some Latter Day Saint drivers, though we failed to find definitive evidence so far.

https://drive.google.com/file/d/123Y8_sbTebF_sm_AcUcs4BqjjQcNxyeC/view?usp=sharing

#heritage #quarries #mines #slate #wales #cymru #industrialarchaeology #ia