A study of limestone quarrying at Llanymynech
Written in 1984 by Harvey Kynaston
THE HOFFMAN KILN
STRUCTURE, LOCATION AND FUNCTION
STRUCTURE OF THE KILN
At the turn of the century there was a demand for finer lime than the familiar inverted bottle shaped kilns could produce. It was decided to build a superior type of kiln at Llanymynech which could provide lime by firing with less coal therefore producing a finer lime for industry. The Hoffman kiln today is very much overgrown. Plants such as ferns, mosses, nettle and ivy have taken a firm hold on it and there are even a number of sizeable lime trees on and around the site.
Despite this ever encroaching vegetation, the condition of the kiln is remarkably good. Its oval shape with steep sloping sides has a circumference of approximately 110 metres and each long side has a length of 40 metres. At one time the entire kiln was covered by a curved galvanised roof but this has long since disappeared, leaving a total height from the present day floor of about 4 metres or 40 layers of bricks. While counting these layers it was interesting to note that each layer alternates, having bricks lying end on then side on and so on.
At one end of the kiln (nearest the canal) stands a tall square section chimney approximately 30 metres high which took the smoke away from the area and probably served the purpose of "drawing" the draught through. Over the years its double skin of bricks has weakened and now it is supported by an iron brace.
Along each side of the kiln are 6 arches 1.25 metres wide and 2.20 metres high and they provide entrance to the formidable interior in which stands a long central pillar to support the roof. In the roof can be seen small square holes spaced out at regular intervals. The function of these will be discussed later.
To the left hand side of each arch is a draught hole 90 centimetres wide and 80 centimetres high leading into the kiln and also beneath its floor.
Approaching the site from the A483 one can still catch glimpses of the sleepers and rails of the tramways which served the kiln with trucks carrying limestone or coal.
It has already been mentioned that this structure was intended to produce a finer lime at the turn of this century. It is one of only a few in the country, if not Europe, and by looking at the 1.70 metre thickness of its walls, it was surely built to last. And yet the Hoffman kiln closed down in 1914 and was therefore only in production for about 20 years. Why this was so is one of many unanswered questions. Perhaps one or all of the following possible reasons led to its closure:
Complaints of smoke
Better quality limestone at Porthywaen
Outbreak of first world war
Poor maintenance and deterioration of the canal
The Hoffman kiln never performed well