No problem.  I delete ours regularly.
TSM doesn't make any use of the STGNEW, STGREUSE, and STGDELETE entries.

As far as I know, the only use for them is in the case where you have to
restore your data base to a back level; then looking at the volhist gives
you an idea of which tapes you need to audit afterwards.

Some people also like to have the VOLHIST entries as sort of an audit trail,
but you can pull a copy off to a flat file and retain it that way.  TSM
doesn't care.