Example of Crown Hole in Allen Smelt Mill Flues

3D Model

The model shows an example of one of the crown holes in the top of the Allen Smelt Mill flues.

There are around 50 holes along the top of a 1km stretch of flue, the holes usually being around 30-40cm square. They appear to have been deliberately engineered, with the holes piercing the soil overburden to enter the flue arching. Stone flags were placed on the 4 sides to hold back the soil, and the hole was then capped with another stone flag. These holes are thought to have been added to the flue after it’s construction, but the reasons behind their installation aren’t understood at present.

This 3D model has been created by volunteers as part of the National Landscape’s Land of Lead and Silver project funded by the National Lottery Heritage Fund and Historic England.

Images taken in July 2024. [Ref. Hole #23, North East Field, Frolar Meadows.]