Blast Furnaces Of Co. Clare & Co. Galway During The 17th & 18th Centuries

A structural survey of three surviving 17th/18th-century masonry built blast furnaces in the town lands of Whitegate, Bealkelly (Co. Clare) and Derryoober (Co. Galway)

We here at ACP have recently been busy enhancing our understanding and knowledge of the development of the iron and steel making industry of Ireland which is an often hugely overlooked part of our cultural heritage. There was a time when our native iron workers could produce wrought iron to almost perfection which would stand its ground against the best iron the world had to offer. As well as that, Ireland has a long history of very talented and skilled blacksmiths who over thousands of years developed methods of working iron not seen anywhere else in the world and some of which are still lost to us today. From the simple yet very effective clay smelting furnaces used in ancient Ireland to the much larger and efficient methods used during the industrial revolution, the making of iron and steel from ore (native or imported) has had a major affect on the country, its people, economy and environment.

We have recently had the opportunity to carry out structural inspections on three 17th/18th-century blast furnaces in Co. Clare and Galway in conjunction with archaeologist, Paul Rondelez, who is currently working to help preserve and document the surviving evidence of Irelands iron industry. Paul has recently received a grant from the Heritage Council to carry out structural and archaeological surveys of each site. Paul and his team have recently completed the clearing each of the furnace sites of vegetation and overgrowth as they have not been used or maintained for a very long time. This allowed access to each site for a complete survey.

Whitegate:

Our first stop with Paul was the furnace at Whitegate, Co. Clare. The site is located on the boundary of three separate properties and is largely in ruin apart from the North and West walls. When constructed, the furnace at Whitegate would have measured 80m2 on the ground and approximately 7 – 8m in height. The type of blast furnaces that emerged in Ireland around the 16th/17th-centuries produced cast iron from iron ore smelted with charcoal. They were large masonry built structures surrounding an inner chimney which was widest at the bottom. The outer walls ranged in thickness from 2 – 3m which provided a massive amount of thermal mass which was necessary to bring the inner chamber up to the required temperature to produce cast iron (Approx. 1400o – 1500o C). There were typically two large arches formed on two adjoining sides of the building. One arch was the tapping arch where the fire was tended and eventually the slag and ore would be tapped from here at the end of the process. The other arch was to allow for a huge bellows generally worked from a water wheel to provide a constant blast of air to the furnace.

An interesting feature at Whitegate is a small tunnel which runs along the North and West walls with a small slit window to the West. It is large enough to walk through but as of yet its purpose is not clear.

Bealkelly:

After parking up in the lovely area surrounding Bealkelly Woods and a short walk through some fields (with permission of course!) we were met by a most beautiful structure hidden away in the lower corner of a field. The furnace at Bealkelly is an amazing example of the level of skill and ingenuity involved in Irelands iron industry. Tucked away from what we now consider normal life, this forgotten piece of our heritage once had a small bustling industry surrounding it. The channel that was cut through the field to bring water to the wheel is still faintly visible, a major undertaking in itself. Every furnace would have to have a number of raw materials constantly on hand to function efficiently.

Charcoal was made in huge quantities to supply enough fuel to the hungry furnace fire. Many men were needed for felling the trees and converting them to charcoal which would have been sorted, graded and stored before use. Iron ore would also have to be gathered in great quantities to produce the ever increasing amount of iron needed in the country. As well as the iron and charcoal, other materials would occasionally be added to the fire depending on what was needed. Some ores may contain too much of a certain element which may decrease the quality of the iron produced. Materials added to the fire may have acted as a flux also to help remove the slag from the iron.

The remaining structure at Bealkelly is in a surprisingly good condition. There is no major failure of the masonry work apart from damage to one of the arches. Slag is easily found in the surrounding area suggesting that this site was well used in its day.

Derryoober:

A few miles over the border in Derryoober, Co. Galway is another hidden furnace. A short walk down a steep field leading into the valley, one can find a lovely little furnace almost asking to be fired up again. Although the reason that feeling may be apparent when you first see the furnace is that there may be evidence to suggest that this furnace was built but never used. One of the main clues being that there is no slag to be found in the immediate area. Generally after a successful burn the slag would be tapped from the mixture and would account for anything up to a third of the mass.

Slag is a mixture of silicates and other material contained within the ores. When liquid it is lighter than iron and sits on the top of the molten mass. The slag can be tapped separately from above the iron. When it cools and solidifies, slag has a glass like appearance and may show various colours depending on the type of ore. The slag from a furnace contains a wealth of information regarding how it was made. The charcoal contained in the slag can be dated and analyzed to assess the amount of heat involved in the process and even the quality of iron which would have been produced.

Another point to note is that there does not seem to be a readily accessible source of water to power the bellows. This would have been a major oversight on the part of the original constructors or it is possible water was to be channeled from further afield but the plan never worked. It is also just as likely that once the furnace was built there was no money left for further development. Apart from that the furnace is in a good structural condition. The top of the furnace may have been reduced over time as it is much shorter than the others. The tapping arch is in good condition and the render still remains around the opening. The bellows arch has been robbed out of the timber structural support beams but is relatively sound.

These monuments are a testimony to an important part of Ireland's history and the global history of iron production and fully deserve to be protected, studied and admired.