For centuries it was the material which protected buildings across Britain – both humble and magnificent – from the elements, before the slate workings which produced it were abandoned in the late 1960s.
As reclaimed slate from derelict farm buildings became cheaper to find, Collyweston slate from mines in Northamptonshire and Lincolnshire was no longer required.
But now one of the country’s oldest Collyweston mines has re-opened and its distinctive limestone tiles will soon adorn one of the roofs at King’s College, Cambridge.
Nigel Smith inspecting a seam of slate in his newly re-opened mine in Collyweston, Northamptonshire, sixty years since it was shut down. Credit: John Robertson/Barcroft Images/The Telegraph
Mining consultants told Mr Smith he would be able to extract around 200 tons of Collyweston slate a year over the next 10 years before the mine was exhausted.
At the same time he was approached by King’s College to supply them with £350,000 worth of slate for a new roof to replace the existing one on Bodley Court, whose uninsulated tiles have become thin and degraded from being exposed to condensation caused by its central heating.
“That sealed the decision to re-open really,” said Mr Smith, 50. “Now we’ve also been approached by other building owners, including Clare College, Cambridge, with a view to supplying and fitting a new slate roof for them.”
Slate from Collyweston mines across the region – including the abandoned one bought in the 1980s by Mr Hope’s father Claude, now 83 – can be found on farm buildings and ancient manor houses around Britain.
The material was used on London’s Guildhall – the home of the City of London Corporation – and can even be found on a 19th Century manor house on Long Island, New York.
But not everyone welcomed the idea of the Collyweston mine re-opening.
Indeed Collyweston Parish Council – fearing the noise and traffic which mining would bring – objected to planning permission, before it was eventually granted by East Northamptonshire Council tas a way of helping to preserve the local character of villages in the area.
Mr Smith said: “The parish councillors asked why people couldn’t use concrete imitation tiles instead. Some of the villagers were also nervous about us re-opening, until we showed them round the mine. They are very supportive now.”
The Claude N Smith Collyweston slate mine has now hired three miners, along with two ‘clivers’ and two ‘dressers’ to work the seams, which extend for hundreds of acres 20 feet beneath arable land around the village.
The clivers split the mined blocks of slate along their natural veins after they have been frozen for eight hours at a time, before the dressers finish off the individual tiles.
Before work began on extracting slate from the mine decades of rubbish dumped there had to be removed. But there was also the tricky question of a colony of bats which had made the old mine its home.
These have now been moved to one half of the mine while other areas are worked. When those seams are exhausted the bats will be moved across so the process of mining can continue.
Historic England stipulated that the slate used to restore the roof at Bodley Court, laid originally in 1893, should come from the Collyweston mine, due to its historical significance.
Work has begun on mining the slate and the new roof is expected to be finished in 2018.
Shane Alexander, King’s College’s clerk of works, said: “There is evidence that Collyweston limestone slate was used as far back as the Romans.”
Philip Isaac, Domus Bursar at King’s College, added: “The College will be re-roofing Bodley’s Court using Collyweston stone as part of a refurbishment of the building in 2018 – 19, in line with recommendations from Historic England and Local Conservation Officers.
"This distinctive stone, which is used on a number of buildings throughout this part of the country, adds to the architectural character of the College and sits well with the nature of the Court.”
Source : www.telegraph.co.uk – Patrick Sawer – March 2017