TheRichFather: Due to medical problems and the fact that I am no longer traveling through the area, I am archiving this cache.
And to finally explain this one to all the non-finders, you cannot estimate distance on this one. The coordinates were approximate since you're underground for the find.
The clue was in the hint. One half did not refer to the distance in the tunnel, it referred to a specific piece of graffiti on the walls that if you looked up near this particular spot, you would have found the cache.