Small Aircraft
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 9
Workload; Situational Awareness
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Speed All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance
Human Factors
I was working the Local Control and Clearance Delivery positions combined. Traffic was fairly complex and busy. I was sequencing VFR arrivals and departures with IFR arrivals and departures as well as working VFR overflights and ground traffic and runway crossings to a compromised runway (K1 at Runway 35 is closed; and has been closed for an unreasonable period of time). The main exit (K4) for landing small aircraft to Runway 35 in the North configuration is also the main departure point.When the incident happened; I was sequencing two VFR aircraft in front of Aircraft X on final; I was also sequencing southbound VFR traffic over the I-15 freeway. In order to land the two inbound VFR aircraft I requested Aircraft X reduce speed; I also requested the following Aircraft Y reduce speed and/or accept a change to Runway 34R to prevent a separation loss or possible go around. When I felt that the situation would not work I requested Aircraft Y make an S turn to create space. While exiting; my landing traffic Aircraft Y over-extended the S turn and came in close proximity (approximately 1.4 miles) to the southbound VFR Aircraft Z. I was visually observing the aircraft; however I may not have issued the traffic call before Class B airspace separation was lost.I could have not attempted to land the two VFR aircraft until later. I could have told Aircraft Y to make a 'small S Turn.' I could have sent either Aircraft X or Aircraft Y around when I felt it wasn't going to work; rather than request the S turn. I recommend flow and speed control training to S56. When sequencing large jets with small general aviation aircraft; they need to be more aware of performance differences.
SLC Tower Controller reported an unsafe operation between three aircraft that resulted in a loss of separation.