jblogo

Area: c. 0.1 hectres.

Description and Reasons for Notification:

This is a new site.

 An old manganese mine in Lower Carboniferous chert, worked opencast and partly underground in a large cavern-like excavation. The ore is strata-bound and is worked downdip in the chert bed, where it is present as pockets. An adit level with a small dump at its mouth connects with the lower levels of the workings, but is not accessible. Side passages to the main cavern were made to exploit pockets of ore and the ore can still be seen in situ. The primary mineral is rhodonite, but this was too hard to work and only where this has been altered extensively to black ore (mainly pyrolusite) was the deposit mined. Excellent specimens of jasper, rhodonite and pyrolusite can be obtained from the mine itself and from the dumps surrounding the quarry excavation and partly filling it. 

The site demonstrates clearly the relationship of the mineralisation to the chert bed and in addition is an important source of manganese minerals.