Narrative:

I was working aircraft X down from his cruising altitude to start the RNAV a approach. There were multiple aircraft departing that I needed to vector north of aircraft X to allow him to descend into the airport. I then went back to clear aircraft X into the holding pattern at the initial approach fix knowing that I wanted to get him low due to the departures from approach. As I scanned the mia (minimum IFR altitude) around the IAF (initial approach fix) I realized that 13000 ft was the lowest altitude I could use around the IAF and immediately issued the holding clearance to aircraft X. As aircraft X read back the clearance I continued to scan the mias in the area around him and realized that he was in a 14000 ft mia and descending out of 14;700 ft. I immediately corrected myself and told aircraft X to maintain 14000 ft. The aircraft read back maintaining 14000 ft. Due to the quick descent rate that the aircraft was using to descend; he went through 14000 ft down to 13600 ft. The aircraft then climbed to 14000 ft and was able to continue inbound for his approach after the first inbound cancelled his IFR flight plan.this was an error made by myself during a busy session. I did not scan his entire route when issuing this altitude to maintain. I was only thinking about where he was holding.

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Original NASA ASRS Text

Title: ZLC Center Controller reported inadvertently descending an aircraft below the Minimum IFR Altitude.

Narrative: I was working Aircraft X down from his cruising altitude to start the RNAV A Approach. There were multiple aircraft departing that I needed to vector north of Aircraft X to allow him to descend into the airport. I then went back to clear Aircraft X into the holding pattern at the Initial Approach Fix knowing that I wanted to get him low due to the departures from approach. As I scanned the MIA (Minimum IFR Altitude) around the IAF (Initial Approach Fix) I realized that 13000 ft was the lowest altitude I could use around the IAF and immediately issued the holding clearance to Aircraft X. As Aircraft X read back the clearance I continued to scan the MIAs in the area around him and realized that he was in a 14000 ft MIA and descending out of 14;700 ft. I immediately corrected myself and told Aircraft X to maintain 14000 ft. The aircraft read back maintaining 14000 ft. Due to the quick descent rate that the aircraft was using to descend; he went through 14000 ft down to 13600 ft. The aircraft then climbed to 14000 ft and was able to continue inbound for his approach after the first inbound cancelled his IFR flight plan.This was an error made by myself during a busy session. I did not scan his entire route when issuing this altitude to maintain. I was only thinking about where he was holding.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.