Roof bolter operator had finished setting two 6' torque tension bolts & waited for his offside partner to finish his, when a rock 3'x 3'x 2"" thick fell from between bolts & knocked his hard hat off, hitting his right hand. A second piece of rock fell and lacerated the back of his head. (the roof is mixed & 7.5 feet.) The laceration required 8 staples. #2 Section, 4R, inby spad 2579