Allen smelt mill flues

21 August 2024

If you’ve ever been to Allendale in Northumberland, you can’t have failed to notice the two chimneys on the top of Dryburn Moor above the village.  This pair, one still standing, one truncated, form part of a large Scheduled Ancient Monument which includes the factory complex of lead smelting ore hearths, furnaces, and bingsteads next to the river East Allen and the long flues which carried lead fume more than two miles to the chimneys on top of the fell.

The North Pennines National Landscape worked to consolidate and interpret the ruin of the factory complex as part of its Allen Valleys Landscape Partnership between 2014 and 2018. Further funding from The National Lottery Heritage Fund and Historic England is now allowing us to conserve the flues at Frolar Meadows as part of a new project called Land of Lead and Silver.

The Frolar Meadows flues are an urgent priority for the project in light of the danger of collapse and use of the land for cattle grazing, and so this is the first of a number of conservation or consolidation projects to get started.

The project has been in design for several years, with the proposals first presented to the Allen Valleys Local History Group at a public meeting in 2019.  Since securing the funding, tendering the design work and securing the contractors, we’ve been able to explore the flues using drones flown through them. The flues were in worse condition than anticipated and it was discovered that what was previously thought to be a mortared construction was in fact dry-stone. What looked like mortar was actually contaminated soil.

The conservation and repair works have been redesigned as we’ve discovered more, with the regular involvement of Historic England’s Inspector of Ancient Monuments, who has to consent any works.

If you’re passing the site, the presence of an excavator may look slightly alarming on such an important and sensitive monument, but the works taking place are designed to preserve as much of the structure as possible and make the structure stronger by addressing its two main weak points:

Firstly, the collapsed flue ends are being taken back to a solid structure and then supported and buried to preserve them.

Secondly, there is a series of hatches in the tops of the flues, which occur around every ten metres. These appear to have been made after the flues were constructed and would either have been used to release fumes before scraping out the condensate, or to draw the fumes from the furnace by lighting intermediate fires underneath, or both. It is now known that these hatches are the points at which most collapses start, so each hatch is being strengthened using a concrete plug.

It is hoped that these interventions will preserve the flues here for at least another 50 years.

During the development stage of the Land of Lead and Silver project, volunteers were trained in photogrammetry work which, alongside Historic England specialists, has allowed us to accurately record the flues as they were. We are working closely with Historic England to ensure that all records all properly archived.

More detailed information about the flues and the current work can be found on this blog post from Tony Liddell, who is providing the archaeological watching brief for the works.

The Land of Lead and Silver project is funded by The National Lottery Heritage Fund and Historic England.