Visitors are encouraged to identify the objects using a quiz sheet. Children, in particular, find that the quiz makes them look more closely at the exhibits and use reasoning and logic to identify them.
Images around Llanymynech
Lime is made from heating limestone. Its use in building mortars, renders and in agriculture has been known and used by early civilisations.
Its widespread use only became possible in the late 13th century when the use of coal made it a cheap resource.
18th century kilns can be found on Llanymynech Hill close to the area of quarrying. The quicklime produced was carried down the hill by pannier ponies. The coming of the canal encouraged the building of inclined planes to transport the rock down the hill.
Canal and later rail transport allowed limestone quarrying and burning – to produce quicklime – to expand rapidly. The canal reached Llanymynech by 1786 and was specifically constructed to this area for the transportation of limestone from the hill. Lime products were used by farmers to ‘sweeten’ the land, by builders for mortar and by ironmasters to extract iron from iron ore. Most of the industrial remains today are from the 19th Limeworks.
Massive draw kilns were built in the 1870s, possibly in association with the railway. The Hoffman kiln was built in 1898/9. It is exceptionally well-preserved and is of particular importance as it still has its chimney. The basic design of the Hoffman kiln dates back to the mid 19th century. Originally developed for use in brickmaking, the design was first patented in Germany in 1858 by its inventor, the engineer Friedrich Hoffman. It was later modified for lime burning. Humphrey Chamberlain took out an English patent in 1868.
The main structure of the Hoffman Kiln forms an oblong shape 150′ long by 50′ wide overall with rounded ends. Built entirely from local Trefonen brick, it is a continuous down draft ring kiln for lime burning. The cloister like internal circuit is18′ wide and has coal feeder holes in the roof. There is a curved vaulted section down the centre of the kiln for the flue.
Set into the outer walls of the kiln are 14 limestone loading doors known as wickets, 6 on each side of the kiln and one at each end. The internal rectangular ring was divided into 14 burning chambers. The rock was stacked from floor to ceiling inside these chambers in the form of a series of dry stone walls constructed between the coal feeder holes. A series of trace holes or gaps were left at the base of the limestone to allow the fire, smoke and gases to exhaust both through to the next chamber to pre heat it, and to the flue under the floor. Alongside each wicket there is a dual purpose air vent.
At ground level the vent allows air to pass through the wall to the floor of the kiln. Air can also pass through a 2′ deep pit into a flat bottomed 18″ high semi circular flue to the centre of the kiln under the floor. The vents would have been fitted with hinged plates and draw tins to control the draught. The under floor central flue measures 4′ wide and 26″ high and runs longitudinally down the centre of the kiln before passing underground to the chimney.
It is covered by a small grill by the entrance to the kiln. The fire progressed anti clockwise round the kiln. At any one time several wickets would have been open into chambers which were being loaded, unloaded or empty. Other chambers would have been pre heating with hot flue gases, while some would be cooling. Possibly only two or three chambers were burning stone at 1000ºC. The last chambers were easing back after the fire had gone past.
The following video is a brief history of Llanymynech Limeworks featuring Thomas Savin, 19thC quarry owner and railway entrepreneur. Made by Shropshire Mind