CNX MIDSTREAM PARTNERS LP

Incident Narrative

"ON 02/10/2025, A LANDOWNER CONTACTED A CNX REPRESENTATIVE TO INQUIRE ABOUT AN AUDIBLE POTENTIAL GAS RELEASE AT THE MOR40 VALVE SETTING. IT WAS INITIALLY ASSUMED THE OBSERVED NOISE WAS FROM CONTEMPORANEOUS CNX PIGGING OPERATIONS BLOWING DOWN THE BARREL AT BAILEY VALVE SET TO LAUNCH A PIG. THE CNX REPRESENTATIVE CONTACTED THE LANDOWNER BACK TO RELAY THAT INFORMATION AND THE LANDOWNER THANKED THE CNX REPRESENTATIVE FOR THE RESPONSE. DURING THIS PIGGING OPERATION THAT WAS CONDUCTED PURSUANT TO CNX PIGGING PROCEDURES AND OPERATIONAL PARAMETERS, THE PRESSURE INCREASED IN THE 1260 MOR40 U2 PIPELINE (UPSTREAM OF THE PIPELINE BEING PIGGED). BASED ON A TREND OF THE DATA, THE PRESSURE APPEARS TO HAVE REMAINED BELOW THE MAOP OF THE PIPELINE AND THE SET-POINT FOR THE PRV LOCATED UPSTREAM AT THE MOR40 WELL PAD. HOWEVER, THE PRV OPENED AT THIS TIME. THE PRV REMAINED OPEN AND RELEASED GAS UNTIL A PRODUCTION OPERATOR ARRIVED ONSITE APPROXIMATELY TWO HOURS LATER AND FOUND THE PRV RELIEVING. THE PRODUCTION OPERATOR SECURED THE RELEASE WITHIN APPROXIMATELY 9 MINUTES OF HIS FINDING. THE PRV WAS SET TO RELIEVE AT 1300 PSIG; BASED ON THE PRESSURE DATA TREND IT APPEARS TO HAVE RELIEVED AT APPROXIMATELY 1126 PSIG. THE PRV WAS TESTED ON 02/11/2025 AND FOUND TO RELIEVE AT 1148 PSIG; IT WAS THEN RESET TO 1300 PSIG. THE PRV WAS LATER THOROUGHLY INSPECTED BY THE MANUFACTURER (MERCER) WHO FOUND EVIDENCE OF NORMAL WEAR ON VALVE INTERNAL COMPONENTS. THE MANUFACTURER STATED THAT THIS WEAR COULD CAUSE A POTENTIAL LEAK, WHICH IN TURN COULD CAUSE A VALVE TO ACTIVATE BELOW ITS SET PRESSURE; IN ADDITION, THE MANUFACTURER TESTED THE SPRING FOR PROPER FUNCTION AND FOUND IT TO BE WITHIN TOLERANCE. AFTER COMPLETING THEIR INSPECTION, NO DEFINITIVE CAUSE FOR THE SUB-SET PRESSURE ACTIVATION WAS IDENTIFIED BY THE MANUFACTURER. CNX HAS TAKEN THIS VALVE OUT OF SERVICE AND REPLACED IT WITH A NEW VALVE TO AVOID A RECURRENCE."