part of initial mitotic spindle pole body separation GO:0030475 The release of duplicated mitotic spindle pole bodies (SPBs) that begins with the nucleation of microtubules from each SPB within the nucleus, leading to V-shaped spindle microtubules. Interpolar microtubules that elongate from each pole are interconnected, forming overlapping microtubules. Capturing and antiparallel sliding apart of microtubules promotes the initial separation of the SPB. GO:0000073 biological_process mitotic spindle formation (spindle phase one) spindle pole body separation mitotic cell cycle process mitotic spindle pole body organization