How Do They Do It?

Monday 20 September, 7:30pm on Five

This factual series lifts the lid on the incredible engineering behind everyday life. Presenter Robert Llewellyn is on a quest to understand the extraordinary engines, machines and structures that form the backbone of 21st-century living. This week, Robert shows us the fascinating workings of a large-scale coal mine, and demonstrates how packages can be delivered across continents within a single day. “Wonderful stuff, coal: It’s what built the modern world, and it’s still going strong,” Robert says. Forty per cent of the world’s electricity is generated by coal power, with over six billion tons of the material used each year. “Digging up enough to keep the lights on is no mean feat – so how do they do it?” Robert asks. To answer this question we travel to Pittsburgh, USA, to the Bailey and Enlow Fork Mine, which holds the largest complex of tunnels in America. The site mines 20million tons of coal a year, collected by over 200 workers who toil 200 metres below the earth’s surface. After travelling down the mineshaft, the workers have to traverse the 35 square mile network of underground tunnels. At present the coalface is a five-mile journey from the shaft, and it takes half an hour to reach it via the mine’s railway system. First, a Continuous Miner machine carves out access tunnels from the sheer coalface. After every few metres of digging the roof is shored up with metal supports known as ‘ribs’ in order to maintain the mine’s stability. As the exposed rock surface is covered in coal dust it becomes highly flammable and so has to be constantly hosed down by retardant. Furthermore, methane has to be funnelled out of the mine to ensure there is no explosive build-up of the gas. Although the Continuous Miner produces more coal in five minutes than a 1920s miner produced in a day, the machine is used mainly to make room for the Long Wall Shearer. “This beast is armed with a set of teeth a tyrannosaurus would be proud of,” Robert says. With its 300 metre long cutting edge, the shearer can smash out 50 tons of coal per minute. A conveyor belt then takes the coal to the earth’s surface. But how is this amount of material then sorted and shipped out to the world’s power plants?

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