Baron 58/58TC
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 5
Situational Awareness; Communication Breakdown
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued New Clearance
Human Factors
Aircraft X departed on a western heading off of BDN to go southbound. The aircraft was in a shallow climb and was approximately 085 MSL climbing to (I believe) 130 MSL in the area designated to have vectors below the MIA. The MIA they were in was 090 MSL and within about 15 miles the terrain would elevate to about 121 MSL. I felt the climb was too shallow and instructed the Certified Professional Controller In Training (CPC-IT) to turn the aircraft north. CPC-IT issued a 310 heading which was not enough for my comfort. I told CPC-IT to issue a 360 heading to ensure that the aircraft would completely miss the higher terrain.After the aircraft completed the turn and it was able to meet the 090 MSL MIA within the minute. The reason for the report is that we were very close to the boundary of the 'Vector below the MIA' and I cannot guarantee that we didn't spill out as the aircraft completed the turn. I have not had the opportunity to review the session as I had other work related obligations to attend to before the end of my shift.Next time I will tell the CPC-IT what heading to issue rather than a vague 'turn that aircraft north' suggestion.
ZSE ARTCC Controller reported an unsafe situation involving an aircraft that may have been below the minimum IFR Altitude.