EE had started 4 hrs early on night shift. He was to do preshift examinations on roadways. He encountered a loose rib on 5W roadway intake side crosscut 43-44. While attempting to bar down loose coal rib a small portion of rock above coal seam came out, striking his left pinky finger just in front of knuckle causing a laceration. Rock size 8"" wide x 20"" long x 3"" thick.