EMPLOYEE WAS USING A KNIFE TO MARK PLASTIC PIPE (WATERLINE) PRIOR TO GLUING IT TOGETHER. THE KNIFE SLIPPED AND HE LACERATED HIS THUMB AT THE BASE OF THE THUMB ON HIS PALM SIDE. THE INJURY DID NOT CAUSE ANY DAMAGE OR IMPAIRMENT TO THE MINING OPERATION. THE INJURY DID NOT INVOLVE COMPLIANCE, JOB SKIL, PROFIENCY, TRAINING, ATTITUDE, OR PROTECTIVE DEVICES. NOT WEARING PROTECTIVE GLOVES