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40 (XL) — 1929-1930
U.S. Death-rates, 283.
U.S. Explosives, 380.
U.S. Output, 229, 341.
U.S. Safety Record, 360.
Underground Conveying, 6, 119.
Underground Fires, Gases, 227.
Underground Haulage, Accidents, 214.
Underground Roads, 269.
Underground Transport, 90.
Underground Workings, Support, 56.
Under-managers, Yorkshire, 359.
Units, Power and Energy, 244.
Uranium, Age, 185.
Uses, Gas Masks, 257.
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