At a copper mine, the power-study model for a substation feeding the pit and downstream distribution had drifted out of step with field conditions, putting its arc-flash labeling at risk. CEI updated the model against field equipment, then evaluated short-circuit ratings, protective-device coordination, and arc flash. Once distribution was confirmed adequate, arc-flash labels were installed per NFPA 70E and IEEE 1584. CEI also converted a second substation’s drawings into readable single-line diagrams following IEEE and ANSI conventions, giving the site current, code-compliant documentation.