2 miners in a scissor lift tacked a plate, went down to retrieve the welding lead, on the way back up at 16 feet the tacks broke the plate fell 4 feet on ee left arm causing a fracture. Plate was 3 inches by 11 and 3/8 inch. Was tacked at an elevation of 20 feet on 200 dryer. New mine site still in commencing at time of injury.