Odin Mine

Odin Mine is at the foot of the northern slopes of Treak Cliff, near Windy Knoll, and has been worked for minerals over many hundreds of years. Odin Mine was worked for nearly a mile west­wards beneath the shales of Mam Tor but is not known to have produced any Blue John. A branch vein of Blue John within Odin Mine was the Blue Cap Vein, but the reason for this name is unknown and it is not accessible today. The mine finally closed in 1869.

The mineral deposits of the Odin Mine lie within the limestone of Treak Cliff hill. This limestone is about 320 million years old, formed in a subdivision of Carboniferous time known as the Asbian Stage. The limestones are largely composed of the fossilised remains of millions of sea creatures, broken up to form lime-sand with the grains later cemented together to form rock.

Odin Mine is rich in minerals due to its geological history. At the foot of Mam Tor, the strata broke along a east-west line for over a mile. This fracture allowed fluids to flow in. In this case the hot fluids were rich in elements including chlorine, fluorine, sulphate, calcium, barium, lead, zinc and traces of uranium. These elements were deposited as crystals coasting the walls, floors and roof of the fractures and over eons of time the elements began to chemically react. The lead and sulphate formed the lead ore galena (PbS) which has been mined in the area since Roman Times 2,000 years ago. The zinc and sulphate formed sphaperite (blende, also known as black jack ZnS) - although this was not as economically significant as lead sulphide. Then there is fluorite or fluorspar (calcium fluoride CaF₂), baryte (barium sulphate BaSO₄) and calcite (CaCO₃).

For a book about Derbyshire Blue John stone, which by its very nature concentrates on the Castleton area of the Peak District National Park, we would recommend the book by Trevor D Ford on the right. The book also give a good geological history of the area, with many references to the Odin Mine. It explains how the minerals were formed in great detail.