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Keywords:
UK,
BETTWS Y COED,
FESTINIOG,
WALES,
BLAENAU,
RAILWAYS,
TUNNELS,
COSTS,
EXCAVATIONS,
DRIVING,
DRILLS,
DRILLING,
SETTING OUT,
ROCKS,
TUNNELLING,
SHAFTS,
SINKING,
MACHINERY,
EXPLOSIVES,
COMPRESSED,
AIR,
HARD,
HARDNESS
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© Thomas Telford and ICE
1883
