It is a Geological Conservation Review site. The site comprises a network of underground tunnels and surface exposures on the eastern fringe of Compton Wood. The site exposes bedded hematiticiron ore (red ochre) in TriassicDolomiticConglomerates which was deposited underwater as a layered mass of iron oxide pellets of various types, probably in an ephemeral lake or pond fed by hot springs when the Mendip area was occupied by a desert environment some 220 million years ago during late Triassic times.
Red ochre is an iron oxide mineral, which was used in paint-making. It is believed that the mine was owned by Mendi Oxide & Ochre Co. Ltd., of Wick.