CLOSE PROX ACR-MLG GA-SMA NEAR SAT ARPT.

Narrative

WE WERE CLRED INTO POS TO HOLD ON RWY 3; WE VISUALLY CLRED THE ARR AREA AND TOOK POS. THE MAIN RWY WAS CLOSED AND A SMALLER PARALLEL RWY WAS BEING USED FOR GA TFC WHICH WAS VERY BUSY. WE SAT IN POS FOR SEVERAL MINS AND THEN WERE INSTRUCTED TO IMMEDIATELY CLR THE RWY AT THE NEAREST EXIT. WE DID SO AND AS WE TURNED OFF THE RWY WE OBSERVED A WDB ACFT LNDG ON OUR RWY. WE SUBSEQUENTLY WERE RECLRED FOR TKOF ON THE SAME RWY. AGAIN THE CTLR WAS VERY BUSY WITH SMALLER ACFT AND WAS LATE IN HANDING US OFF TO DEP CTL. AS WE WERE INSTRUCTED TO CHANGE OVER WE HEARD ANOTHER GAR ISSUED AND ANOTHER ACFT TOLD TO DO A 360 DEG ON FINAL. OUR DEP CLRNC WAS TO 5000 FT AND AT THE TIME OF OUR INITIAL CONTACT WITH DEP WE HAD CLBED THROUGH APPROX 3800 FT. DEP ISSUED US AN IMMEDIATE LEVEL OFF AT 4000 FT AND 2 O'CLOCK TFC. TCASII ISSUED A TFC FOLLOWED BY AN RA TO REDUCE CLB. WE WERE ABLE TO LEVEL AT 4000 FT AND OBSERVED A SMALL ACFT PASS DIRECTLY OVERHEAD. A LITTLE LATER ON THE HDOF FROM TWR AND THE RESULTS COULD HAVE BEEN DIFFERENT. THE WORKLOAD OF THE TWR CTLR ALONG WITH NORMAL RWY CLOSURE CONTRIBUTED TO THIS SERIES OF CLOSE CALLS. TCASII IN THIS CASE ALSO CAME VERY CLOSE TO BEING THE ONLY CHK LEFT ON WHAT COULD HAVE BEEN A SERIOUS PROBLEM. I DON'T KNOW SPECIFIC ATC PROCS OR SEPARATION IN THESE INSTANCES BUT FEEL DEV FROM THESE RULES OCCURRED OR WAS VERY CLOSE.