A "dead hole" is a hole where the width of the shot at the point measured at right angles to the line of the hole is so great that the heel is not of sufficient strength to at least balance the resistance at the point. The heel means that part of the shot which lies outside of the explosive.
225 ILCS 705/20.23
No person shall drill or shoot a dead hole as hereinafter defined
Laws 1953, p. 701.
Official source: Illinois General Assembly. Reproduced from public-domain Illinois statutes; confirm against the official source for the current text. Not legal advice.