There was an old short story or novelette that centered on changing your permeability so that you could walk through solid stone. The protagonist was a prospector, and at one point he accidentally walks through the remains of another prospector whose device failed. It was probably written by an American during the Cold War. Any ideas as to the title and author? This is not one of the Ringworld books, where permeability of scrith became a talking point.
This was written by Harry Harrison during the early 1950s, so indeed during the Cold War.
In this story, there’s a "walk-through" that allows the user to move through solid stone:
Pete had been a rock diver for eleven years, yet the sight of this incredible environment never ceased to amaze him. He took the miracle of his vibratory penetrator, the rock diver’s "walk-through," for granted. It was just a gadget, a good gadget, but something he could take apart and fix if he had to. The important thing was what it did to the world around him.
At one point, the protagonist does indeed walk through the remains of another diver:
Pete remembered it, too well. He had been dog-tired and sleepy when he had walked through that hunk of rock that hadn’t been all rock. Soft-Head was standing there—trapped for eternity in the stone. His face was horror-stricken as he stood half bent over, grabbing at his switch box. For one horrible instant Soft-Head must have known that something was wrong with his walk-through—then the rock had closed in.