STIR boiling water into dry gelatin mix in large bowl at least 2 min. until completely dissolved. Add enough ice to cold water to measure 1-1/2 cups. Add to gelatin; stir. Remove any undissolved ice. Refrigerate 30 min. or until slightly thickened (consistency of unbeaten egg whites.)
STIR in melon balls and mint leaves. Spoon into 9x5-inch loaf pan.
REFRIGERATE 4 hours or until firm. Unmold. Store leftover gelatin in refrigerator.