In Galant v. Department of Environmental Resources, 534 Pa. 17, 20 n.2, 626 A.2d 496, 498, n.2 (1993), the Court stated that just cause "must be merit-related and the criteria must touch upon the employee's competency and ability in some rational and logical manner." "What constitutes ample just cause for removal must necessarily be largely a matter of discretion on the part of the head of the department. To be sufficient, however, the cause, should be personal to the employee and such as to render him unfit for the position he occupies...." Woods v. State Civil Service Commission (New Castle Youth Development Center), 590 Pa. 337, 345, 912 A.2d 803, 809 (2006). The Commission is the sole fact finder and has exclusive authority to assess credibility and resolve evidentiary conflicts. Hetman v. State Civil Service Commission (Berks County Children and Youth), 714 A.2d 532 (Pa. Cmwlth. 1998), petition for allowance of appeal denied, 558 Pa. 634, 737 A.2d 1227 (1999).