|
In the 1860's endless miles of railroad tunnels were drilled in the Sierra Nevada Mountain granite, by hand, with similar, only larger versions of that drill. I believe two laborers wailed on that bar with sledge hammers while another held it steady. When the hole was 18 inches or so deep, you filled it with black powder, inserted a few feet of fuse, screamed "fire in the hole," and ran like hell.
When the steam hammer/drill was invented, daily linear footage increased exponentially and the John Henry's on the crew were "re-trained" for more technical work.
|