Many internet years ago, I ran into a discussion where a supplier of
compressed air powered tools was trying to figure out why so many
mining operations used so many compressed air powered tools. From the
orders and replacement parts he could figure out how much compressed
air had to be produced at each location. It was off the chart. He felt
he understood the application of his equipment and that use in the
mining sector was way out of proportion several times over. In the
discussion no one was able to produce even a reasonable speculation.
Many years later I ran into the absolutely mind bubbling answer.
Harness Hydro Power with a Trompe
The story of mechanics The science of captive force or development of
machine power in this industrial age.
1930 A. Russel Bond,
Ragged Chutes: A Modern Wonder Over 100 Years Old!! (see blow-off
valve in action at the end of the page)
Illustrated Description of the Taylor Hydraulic Air Compressor and
Transmission of Power by Compressed Air (1897)
-Gaby de Wilde
Sorry I missed it. Simple answer; explosive gases and electricity
are a bad mix. Compressed air tools are much less likely to cause an
explosion, and if there's a cave-in your tool's power supply might
save your life. You can't breathe electricity...
Mark L. Fergerson
Right, that makes sense.
I do think the conspiracy with the occult underground free energy
technology makes for a better story.