Minllyn is a slate and slab quarry (nprn 310049) begun in the C19, the most productive phase of which began after the Carlyle Slate & Slab Company was formed in 1872. Work ceased in 1924. The oval spoil tip is on steep ground below a small quarry (nprn 527490). It measures 25m SSE-NNW x 15m. It is up to 8m high on the downhill (S) side and contains slate waste, with a thin covering of turf.
Recorded as part of RCAHMW Uplands Initiative Project, W B Horton, H&H, 19/12/2012.