ENS 57976

v t e ENS Event
12:00 Oct 9, 2025
Title	Gauge Shutter Failure
Event Description	The following information was provided by the Minnesota Department of Health (MDH) via email: The radiation safety officer (RSO) was attempting to lock-out an Ohmart, Cs-137 fixed gauge when they found that the shutter was stuck open. The RSO stated that while trying to close the shutter, they chipped it. At that point, they removed the gauge and attempted to close the shutter in their workshop and were still unsuccessful. The RSO stated that, during continued attempts to close the shutter, they further damaged the shutter. At this point, the RSO fixed a 6-inch steel plate over the beam and put the device in storage. The RSO took surveys and determined the source was adequately shielded. The device will remain in storage, and the gauge manufacturer will be consulted for next steps. The RSO reported the event to MDH at approximately 1200 CDT on October 9, 2025. Manufacturer: Ohmart Model: unknown at this time Source: Cs-137 Activity: approximately 80 millicuries Minnesota Event ID: MN250007

ENS 57976 +/-
Where
Cleveland Cliffs Minorca Mine Virginia, Minnesota (NRC Region 3)
License number:	1088
Organization:	Minnesota Department Of Health
Reporting

Agreement State
Time - Person (Reporting Time:+4.38 h0.183 days <br />0.0261 weeks <br />0.006 months <br />)
Opened:	John Miller 16:23 Oct 9, 2025
NRC Officer:	Sam Colvard
Last Updated:	Oct 10, 2025
57976 - NRC Website
v • d • e

v t e Emergency Notification System
Cleveland Cliffs Minorca Mine with Agreement State
WEEKMONTHYEAR2025-10-09T12:00:00 [Table view]
[ENS list for Cleveland Cliffs Minorca Mine]

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