An unplanned Roof Fall occurred in the 3rd North Section, in the intersection of #6 Entry and crosscut #9, outby area. The area that caved is approximately 20 sq. ft. and 9 ft. high. No one was injured or entrapped and no ventilation was interrupted. Preliminary diagnoses; Primary Roof Support did not have the resin the length of the bolts as required by the Roof Control Plan.