D01 CTLR DESCRIBES A CONFLICT AT 11000 FT WHILE PROVIDING SEQUENCING VECTORS TO PERMIT CLOSING A RWY FOR SNOW REMOVAL.

Narrative

I WAS WORKING FINAL APCH FOR RWY 35R. DURING THIS TIME THE WX WAS IMC; AND THE ARPT WAS CONDUCTING MONITORED SIMULTANEOUS ILS APCHS. RWY 35R WAS CLOSING FOR SNOW REMOVAL. I WAS TRANSITIONING ACFT ON R DOWNWIND AND BOTH BASE LEGS FROM RWY 35R TO RWY 35L. DURING THIS TIME ACFT A WAS ESTABLISHED ON RWY 35L FINAL AT 11000 FT. ACFT B; WHO WAS ON R DOWNWIND AT 11000 FT; WAS TURNED BASE TOO EARLY TO FOLLOW ACFT A. UPON REALIZING THE CONFLICT; I TURNED ACFT B SEBOUND AND CLBED TO 12000 FT. ACFT A WAS DSNDING TO 10000 FT. ACFT A NOW CONFLICTED WITH ACFT C AT 10000 FT JOINING THE RWY 34R ILS FROM L BASE. ACFT A CAME WITHIN 1.78 MI OF ACFT B AND 100 FT. ACFT A CAME WITHIN 2.1 MI OF ACFT C. I BELIEVE THAT THE RWY CHANGE WAS UNTIMELY AS THERE WERE ONLY 2 MORE ACFT THAT COULD HAVE LANDED ON RWY 35R; NOT DELAYING THE SNOW REMOVAL; BUT REMOVING THE INCREASE IN COMPLEXITY FROM HAVING TO CHANGE THE DOWNWIND TFC OVER TO RWY 35L. THE FINAL RADAR COORDINATOR WAS DISTR AWAY FROM THE SITUATION BY A LESSER PRIORITY; THEREFORE; NOT HELPING CATCH THE EARLY TURN TO ACFT B. I HAD BEEN WORKING STEADY MODERATE TO HVY TFC FOR 1 HR 37 MINS AND WAS GETTING TIRED AND IN NEED OF A BREAK. IN THE FUTURE; DURING UNUSUAL SITUATIONS; I WILL STICK TO THE RULE OF ALT SEPARATION IS YOUR FRIEND.