I called the Ohio Department of "we really don't care cause it will cost us money." You guys can see were this post is heading!
Being Sunday, I caved in the sides with the backhoe simply to cover the opening at both the ground level and at the bottom of the hole on either side. Had my boy, wife, neighbor, or dog, fell in I would have had a major problem. The guy said that since I eliminated the immediate danger, I should call if it opens back up and they will "look" at it again. I'm expecting a complete written report from the state in the mail within the next several days and perhaps there will be more information contained than what I have experienced already. While talking to the man and reading between the lines, he more or less stated that there was mining activity in the vicinity and that this "may or may not" be related to it.