CTLR TRAINING IN PROGRESS AND LTSS OCCURRED BTWN SMT AND MLT USING INTERSECTING RWYS.

Narrative

SMT X WAS ON FINAL RWY 06; TFC IN L PATTERN RWY 30 WAS AN MLT Y. I WAS TRAINING A DEVELOPMENTAL WITH APPROX 70 HRS ON LCL. MLT Y HAD BEEN CLRED FOR THE OPTION RWY 30 AS HE WAS PASSING OVER THE FINAL FOR RWY 06. AT THAT TIME THE SMT X WAS APPROX 6 MI OUT FOR RWY 06. THE SITUATION PROGRESSED AND MY DEVELOPMENTAL MISJUDGED MLT Y HELI SPD AND REALIZED SHE WOULD NEED A LNDG TO HOLD SHORT (1900 FT). SHE ISSUED THE RESTRICTION TO THE MLT Y HELI AS HE APCHED 1 MI FINAL. SMT X WAS 1 1/2 MI OUT FOR RWY 06. MLT Y HELI RESPONDED 'UNABLE.' SHE THEN LET THE SITUATION PROGRESS AND ISSUED MLT Y HELI 'NO DELAY THROUGH INTXN RWY 06 TFC SMT X 3/4 MI FINAL.' AT THE TIME OF THIS CLRNC MLT Y WAS 1/2 MI FINAL. HE ACCEPTED RESTRICTION; BUT IN MY OPINION DID NOTHING TO INCREASE HIS SPD. I TOLD HER (MY DEVELOPMENTAL) TO 'HAVE SOMEBODY GAR' AS MLT Y PASSED TAXIWAY ALPHA (1100 FT FROM APCH END) AND SMT X WAS VERY SHORT FINAL (ABOUT 200 FT). SHE (DEVELOPMENTAL) DID NOTHING. MLT Y HELI OCCUPIED LATERAL LIMITS OF RWY 06 AS SMT X CROSSED THE NUMBERS ON RWY 06 AND DID NOT CLR UNTIL SMT X WAS APPROX 800 FT DOWN THE RWY. PROBLEM AROSE DUE TO MISJUDGMENT ON PART OF DEVELOPMENTAL. SHE TRIED 2 CORRECTIVE ACTIONS AND BOTH FAILED. I CANNOT EXPLAIN THE INACTION ON MY PART; I JUST STOOD THERE AS IT HAPPENED; I LET IT HAPPEN. THIS IS MY FIRST TRAINEE; I HAVE LEARNED A LOT UP TO THIS POINT AND ESPECIALLY TODAY. I WILL OVERRIDE IN THE FUTURE TO MAINTAIN SEPARATION. THIS IS MY TICKET WE'RE OPERATING ON.