mine-run

[Barnhart]

There are perhaps two situations in the examples you've  given:

(1) Very possibly a typo for nine-run eighth inning.

4/19/01 Newsday, "Brian Daubach strokes a three-run homer during
Boston's
mine-run eighth inning."

(2) A term recorded in MW3 meaning either the "unsorted product of a
mine" or in a figurative sense "product of common or average grade"

3/11/01 News & Record, "They do tend to make ordinary, mine-run
politicians
look a little dingy by comparison."

07/18/94 American Lawyer Newspapers Group, "In the 'mine run' of cases
it
may not be so very difficult because more or less similar cases have
blazed
trails."

Regards,
David

barnhart at highlands.com