At a mine of the Sunnyhill Coal Co. near New Lexington, Ohio one day last week, amazed mine experts watched a huge (26-ton) machine in action. With surprisingly little noise, it tore into a seam, spewed a continuous stream of coal into a truck that followed. Within a minute and a half, the five-ton truck was almost full; in that time the machine had come close to the average U.S. production per man-day (around five tons). The machine's lone operator apologized because it had taken so long; he was running the digger at slow speed.
The dream of a continuous...
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