He led an amazing life: the son of Greek immigrants, Mitchell eventually became a billionaire.
But he will be best remembered for fine-tuning the process that has transformed America's energy landscape.
Despite its current ubiquity, the process remains mysterious and controversial. It involves a lot of weird, arcane equipment. And you can't see it happening since it occurs underground).
There is some evidence it has contaminated water; that spent frack fluid injected into the ground causes earthquakes; and that spilled wastewater has neutered farm animals, though the industry vigorously disputes this. If you've been affected by it, you're sometimes not allowed to talk about it.
At the same time, the increased use of
And some say it's actually helping the environment by reducing emissions.
The Cynthia and George Mitchell Foundation is among the organizations trying to make sure fracking is sustainable and environmentally friendly.
We recently went on a tour of a