NORTHERN NATURAL GAS CO

Incident Narrative

BLACK HILLS ENERGY, THE LOCAL DISTRIBUTION OPERATOR, DISCOVERED SOME FROST IN THE GROUND AT THE FARM TAP LOCATED ON THE MASON CITY (IAB72001) 10-INCH BRANCH LINE NEAR MP 4.16. THIS VERY MINOR GRADE 3 TYPE LEAK TOOK 3 DAYS TO REPAIR. FIRST OF ALL, THE FARM TAP AND EXCAVATION COULD NOT BE MADE SAFE ENOUGH FOR EMPLOYEES TO ENTER; AND SECOND, NORTHERN CONTINUED TO PROVIDE SERVICE TO MASON CITY, VENTURA, AND 6 FARM TAPS. ULTIMATELY, THE LINE WAS COMPLETELY BLOWN DOWN SO REPAIRS COULD BE MADE. THE CONTRACTOR AND COMPANY PERSONNEL WERE ON SITE AROUND THE CLOCK DURING THE ENTIRE REPAIR. THE LEAK WAS DUE TO THREAD FAILURE BELOW THE FARM TAP ROOT VALVE. ULTIMATELY, THE OLD TAP WAS CUT OFF AND CONTAINED IN A TYPE B PRESSURE CONTAINING SLEEVE. A NEW TAP WITH A FULL ENCIRCLEMENT SLEEVE WAS COMPLETED AND THE FARM TAP RE-BUILT. THE NRC WAS NOTIFIED THAT THIS WOULD NOT TURN INTO A REPORTABLE INCIDENT. THAT WAS BEFORE WE ACCUMULATED ALL THE COSTS OF REPAIR FOR THIS TINY LEAK. A NOTE WAS SENT TO THE INFORMATION RESOURCES OFFICER THAT NORTHERN WOULD BE REPORTING AN INCIDENT.