No, this isn’t a maze for Swaledale sheep, it’s a cut-away view of the smelting flues used by lead mines in Swaledale: hearth for the smashed up ore on the right, outlet chimney centre and the maze of corridors in between where various minerals settled out from the vapours as they precipitated out.
I suspect that this drawing was a rough for my book Yorkshire Rock, a Journey through Time published by the British Geological Survey in 1996 but still in print today (see link below).
If it was intended for the book, it didn’t make it into the final cut, which instead featured the less technical but more dramatic process of hushing.
Link
Yorkshire Rock, a journey through time at the BGS shop, £6.50.