Little bit below is pasted from delabole quarry website. (www.delaboleslate.co.uk) They currently produce about 110 tonnes slate per day and have been doing that amount for at least the last 100+ years so there is a chance your roof may be Cornish. But their slate ain't 'alf pricey compared to the inferior (imported slate much more brittle and has high wastage rate when laying) but much cheaper Brazilian stuff.
But your roof might also might be Welsh cos rumour has it that they produced a slate or two over the years!!!
Are there any Welsh slate quarries still producing?
' Delabole Slate has been used as a building material for well over 600 years, and has been quarried continuously since the early 17th century, when Carew in his survey of Cornwall wrote "in substance thin, in colour fair, in lasting long and generally carrieth good regard".
The quarry is 425 feet deep and more than a mile and a half in circumference, and provides a quality of slate that is exceptional.
During the reign of Elizabeth I, the five quarries that existed within the vicinity of the present pit assumed considerable importance, delivering slate "throughout the realm, and even exporting it by sea to Brittany and the Netherlands".
In 1859, in Murrays Handbook of Devon and Cornwall, the author wrote "the quarries present one of the most astonishing and animated scenes imaginable". About 1,000 men were employed at this time, raising an average of 120 tonnes of slate per day. Long before the coming of the railway, the slate was cut and hauled six miles to Port Gaverne where it would be loaded onto vessels moored in the harbour area. It would take thirty wagons, pulled by over a hundred horses to load a sixty ton ship and as late as 1890, women still assisted with the stowing of slates.
In 1841, the five quarries formed themselves into a single controlled unit, and the Old Delabole Slate Company was formed, becoming the present Limited liability company in 1898.
Today, by applying modern mining techniques and utilising only five skilled quarrymen, an average of 120 tonnes of slate block is still quarried each day. Using the latest diamond wire saws, 600 tonne blocks are sawn from the quarry face, eliminating the age-old method of blasting. Wire sawing improves recovery, thus preserving for future years valuable reserves of slate, and finally laying to rest the historic building of waste mountains.
Alongside these technological developments there remains no substitute for the skill and experience of the traditional Cornish craftsman. '
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