I have serious doubts that a Hummer would be able to get 32 mpg going down a mine shaft with a tailwind, diesel or not. He might be getting 32 miles per diesel gallon, when you count the vegetable oil mixed in. But he's not getting 32 mpg. If all he's doing is filtering his oil through a pair of blue jeans, he's going to be buying new sticks, and probably a new IP, before too much longer.
"To destroy this invisible Government, to dissolve the unholy alliance between corrupt business and corrupt politics is the first task of the statesmanship of the day." - 1912 Progressive Party Platform, Theodore Roosevelt