Llanymynech Limeworks

At the foot of Llanymynech Hill, beside the Montgomery Canal, is an industrial site that lets you read a whole process from rock face to boat in about half an hour on foot.

The Hoffmann kiln

The centrepiece is a large oval structure with a tall chimney, built around 1899.

The Hoffmann kiln, patented in Germany in 1858, solved a problem with conventional lime burning: an ordinary kiln has to be heated, burned, cooled and emptied in a cycle, which wastes an enormous amount of fuel and time.

In a Hoffmann kiln the fire moves instead. A ring of chambers surrounds a central flue, and the burning zone travels round the ring while chambers behind it cool and are emptied and chambers ahead are loaded. Burning never stops, and the hot gases from the fire preheat the next chambers on the way to the chimney.

Very few survive anywhere in Britain. This one has been consolidated and is publicly accessible with interpretation, which makes it one of the more instructive industrial monuments in Wales.

The rest of the process

The quarry. The faces on the hill above are enormous and dominate the village. Limestone here is high quality and was in demand for agriculture, for building and, most importantly, as flux for ironmaking.

The incline. Stone came down from the quarry by a gravity-worked incline, loaded wagons hauling empty ones up.

The draw kilns. A bank of older intermittent kilns stands alongside the Hoffmann, showing the technology it replaced.

The wharf. The Montgomery Canal runs past, and burnt lime went out by boat. The canal was built for lime and coal, and there is no better place in Powys to see why.

The older workings

The same hill contains Ogof, a cave and mine complex worked for copper, with Roman coins and human remains recovered from it. It is one of the few securely Roman metal mines in Wales.

It is a Site of Special Scientific Interest for its bat populations and is not accessible.

The hilltop carries an Iron Age hillfort enclosing around 57 hectares, one of the largest in the Marches.

So the sequence on this one hill runs: Iron Age fort, Roman copper mine, eighteenth and nineteenth-century limestone quarry, canal wharf, Hoffmann kiln, and now a nature reserve on the abandoned quarry floor.

Visiting

Free, open, with parking and interpretation panels. Offa's Dyke Path runs over the hill.

The quarry ground is now managed as a nature reserve for limestone grassland, orchids and butterflies, which is what happens to a worked-out limestone quarry left alone for a few decades. Keep away from the quarry faces themselves.