Area: 2.5 hectares.
Amended at this revision by extension and deletion. In Dartmoor National Park.
In County Structure Plan Nature Conservation Zone.
Description and Reasons for Notification:
These mines are important for research into the mineralogy of south west England. There is also an important roost for bats at Haytor Iron Mine.
This site contains an iron ore deposit, the origins of which are a subject of debate. The ore which occurs is largely magnetite and occurs with hornblende in three beds 3m, 4.5m and 2m thick. The surrounding country rock is an actinolite-garnet hornfels, containing axinite, pyrite, chalcopyrite and pseudomorphs of quartz after datolite. A granite sill seen above the lowest ore bed is the subject of a controversy, still largely unresolved, in discussions over the genesis of the deposit. It was once thought that the iron ores originated in the granite, but later ideas assigned to the granite a role only as a heat source to metamorphose and mobilise iron ores in greenstones or sediments. The mine adit exposes clearly the three ore beds and their relationships with surrounding rocks. The site is important for its research potential as this type of mineral deposit requires more study to reach a clearer understanding of its origins.
Haytor Iron Mine has been an important roost for bats, particularly in the winter, for many years. It is one of several sites around Dartmoor which bats from the Buckfastleigh and Chudleigh colonies use periodically.