EMB ERJ 170/175 ER/LR
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 6.0
Training / Qualification; Situational Awareness
ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued New Clearance
Procedure; Airspace Structure; Human Factors
We were in a north flow. Staggered airspace configuration. Feeders were stacking final so I offered to take Aircraft X from a 110 heading. Aircraft X was originally descended to 13;000 feet. I had a General Aviation(GA) aircraft inbound from the south. I had assigned 13;000 feet to Aircraft X and 12;000 feet to the GA aircraft and then I went back and swapped the altitudes. I didn't realize Aircraft X would not miss the 12700 foot Minimum Vectoring Altitude(MVA). The Supervisor asked me about Aircraft X one mile from the MVA line. I immediately turned Aircraft X 15 degrees and asked pilot if he had the terrain in sight. He did. I instructed the pilot to provide their own terrain and obstruction clearance through the MVA which pilot read back. I realize this is not correct application of this rule. 15 degrees was not enough to clear the MVA. Aircraft X entered the MVA by .4 of a mile for 2.7 miles as they passed over the mountain ridge line.  I should have let the feeders work out their own plan. I had been off for 10 days and this was my first session back. I could have reviewed the airspace more.
A TRACON Controller reported they allowed an aircraft to fly below the Minimum Vectoring Altitude.