Abbey's blast from the past

Historians hope the experiment will reveal more about the colourful past of Rievaulx Abbey, near Helmsley, which in its heyday was not only at the centre of religious life in North Yorkshire, but was also the focus of a thriving industrial community.

The monks are known to have pioneered smelting techniques and numerous Cistercian iron working sites have been unearthed at nearby Bilsdale and Laskill, on the North York Moors.

Their furnaces used locally-mined ore, charcoal and hand-powered bellows to supply metal for fabrication into tools, which in turn were used to quarry stone to build the abbey.

Expert Dr Gerry McDonnell, of Bradford University, also believes the monks were close to developing a type of blast furnace capable of smelting ore in much greater quantities and at higher temperatures, before Henry VIII intervened by closing down the monastery in 1538.

The recreated Rievaulx furnace is based on evidence unearthed during digs and is called a shaft furnace.

Two metres tall and made from clay, it will burn at about 1,100 degrees centigrade, producing iron not as a molten metal, but as a malleable "pancake", known as a "bloom", removed with tongs and worked on an anvil.

English Heritage science advisor Ian Panter said: "There are so many unanswered questions about the way monks produced iron that the only way to resolve them is to rebuild one of their furnaces.

"It will take up to eight hours to reach peak temperature and heat sensors will monitor each burn. Visitors will be asked to help out by pumping the bellows. Slag left over will be analysed and compared with archaeological finds to provide further clues about Rievaulx's industrial past."

The furnace will be fired up again on July 20 and 21 and then left to decay naturally, providing a model for the excavation of authentic medieval furnaces thought to exist in the area.

An archaeology open day takes place at Rievaulx tomorrow, from 11am to 4pm