Military
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 2
Time Pressure
ATC Issue All Types; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued New Clearance
Human Factors
Aircraft X; was a SLC arrival from the south crossing over the Oquirrh mountains. He was initially descended to 13;000 ft. I must have confused him when I asked a speed question. I had slower traffic ahead in the downwind so I asked him if when I had him level at 11;000 ft. in about 20 miles would he be able to maintain 210 kts. He said he could and would slow now. I told him I didn't need it yet and would let him know when I did. I was working some other aircraft and coordinating with ZLC for an aircraft that had filed an altitude too low for their route of flight; when I looked back at Aircraft X he was in a 12;700 ft. MVA at 11;100 ft. He was already passed the ridge line and on the edge of the MVA line so I didn't BRASHR him or change his altitude. By the time I could have given low altitude phraseology he was already away from the MVA and above the ones in his area. There was never an MSAW (Minimum Safe Altitude Warning) alert. I will try and be more clear when asking questions like that (about his capabilities at an altitude not currently assigned).
Salt Lake City TRACON Controller reported a military jet had descended below the MVA.