"My engineers kept telling me, 'You are wasting your money, Mitchell," he told Forbes in 2009. "And I said, 'Well damn it, let's figure this thing out, because there is no question there is a tremendous source bed that's about 250 feet thick.'"

As other companies adopted Mitchell's techniques, U.S. gasproduction rose 25 percent in the past decade, pushing prices to a 10-year low in April 2012. The nation now has an estimated 890 trillion cubic feet equivalent of recoverable natural gas, according to ITG Investment Research. That's enough fuel for almost 40 years at current consumption rates.

And:

Mitchell donated more than $175 million, with the largest gifts going to Texas A&M, the University of Houston and M.D. Anderson Cancer Center. A tennis center at Texas A&M bears his name. His wife, Cynthia, who died in 2009, helped develop the Cynthia Woods Mitchell Pavilion, an outdoor concert venue, in The Woodlands.

In addition to his "great love" for The Woodlands, Richmond said, Mitchell had "an enormous passion" for his hometown of Galveston, Texas, where he bought and renovated older buildings in the downtown area.

David Fuller's view With an inventive mind and a generous spirit, George Mitchell's development of fracking technology is an inestimable contribution to the future of global GDP growth.