It’s not very often that the ground is frozen solid on Belle Isle, the salt dome just a stone’s throw from the Gulf of Mexico. But it happened in 1962 — in the summertime, on purpose.
Cargill was trying to dig a shaft 16 feet wide into the dome, hoping to mine as much as 400,000 tons of salt each year. But the shaft had to pass through a 200-foot layer of “porous soil so saturated with subsurface…