Magic of Making - A Right Royal Roof

Somebody who enjoys the outdoor life and the great beauty of nature is Her Majesty Queen Elizabeth II, which brings us here to the English Lake District, where ducks and holidaymakers alike are waddling around on fine slates of the salt used to tile some of the Queen's royal palaces. Natural erosion caused by wind and rain and ice has carried the stones all the way down from the misty mountains. Erosion of a kind happens inside the mountains too, at the hands of miners. For thousands of years, since the days of the ancient Romans, brave and clever men have been burrowing into these rocks for the highly valued slate of which they are made. This particular slate makes an excellent roof covering and has been used to keep the rain out of some of the world's finest buildings. The miners begin by drilling holes at the base of the slate, meeting inside the rock to form a channel through which a diamond studded wire is threaded. It'll take more than a few burly miners to do the cutting of course. What is needed here is the helping hand of our old friend ye electricity. A powerful motor pulls the wire at high speed to carve out a deep slot under a huge lump of slate that will soon be blasted free. Mining is a very hard and dangerous job and for centuries it's kept fearless folk of strength and stamina hard at it. Highly explosive gunpowder is poured into a tube designed to fit nice and snugly into the hole this drill has been making. To light the gunpowder safely a fuse will be needed. Fuse is carefully made to burn at a timed rate so it must be cut to exactly the right length. The miners use just enough fuse so they have time to get away after the end has been lit. The force of the blast is contained inside the rock with a wad of packing and that's carefully rammed home after the gunpowder by a firm hand wielding a wooden stick. There's a very good reason why we use wood rather than metal for this job. Can you work out what it is? The saw has done its cutting and the powder is in. It's time for man and machine to clear the area while the fuse is set alight. It's very dark down here and one could easily take a nasty knock to the helmet so the miners resist the urge to run away. How long do you think before she blows? By the time it wasn't quite right. The explosion has worked and in amongst the dust and debris many great lumps of slate have been blasted free. And here comes a miner with his prize. A pair of clogs. A clog is the name we give to our slate boulders and some are so big that they must be cut into manageable lumps by an ancient saw. This one has been working on the mine for over a hundred years. Jets of water help to keep the dust down and stop the saw from overheating. The smaller clogs are docked using a hammer and chisel. Slate is a metamorphic rock. It was once a mix of mud and volcanic ash that over millions of years became buried deep in the earth to be heated and squashed so that crystals of mica lined up with each other to form planes of cleavage that can be separated out by riving. Riving is like splitting a pack of cards and this is how the slate is made into hundreds of thin sheets perfect for laying onto our roofs. The sheets are almost ready to leave the workshop but there's one more job to attend to. Dressing. The machine here chips the rock down to the perfect size so the roofer can't complain that his tiles are all different. Even on the highest roofs, these slates should last for hundreds of years which is why they're a popular choice on some of the grandest houses in the land. Have you guessed whose roof we're going to see here? Could this be her bedroom window? The union flag. A bit bedraggled by the rain, I see. Well, that's the British weather for you and why the Queen needs a good roof. How wonderful! Can you see? One of her tiles has been especially engraved with the date that tells us when the roof was laid. And all thanks to our dear old friends, the miners.