I was watching a show called "Monster Machines" on The Learning Channel a while back, and I saw a special on coal mining. There's this one kind of machine called "the long wall." It's really pretty amazing: it's got a huge rotating spiked barrel up front that chews up coal and throws it onto a conveyor belt behind it. Alongside the converyor belt is an automated hyraulic support system that holds up the newly formed wall in the wake of the machine. The coal is collected, I guess somewhere towards the back. Here's the wild part: the miners let the roof cave in behind them. They’re like a moving bubble of life in a world of darkness. Longwall mining yields four to five times more coal than the old-fashioned way of carving rooms and support pillars out of the coal bed because every bit of coal winds up being used.

source: TLC special tags: Church, Commitment