log_miner works on Redo Logs or Archived Logs.
It stores SQLs for all the DMLs as well as SQLs for UNDO of those SQLs.
So yes, you should be able to run it on any log (and any time as long as you have the log) and get the SQL and then run that SQL to undo the changes.

I do wish though that log_miner will one day be capable enough to undo DDLs (drop table etc.) but I think that is a much more complicated issue so for the time being we have to live by point-in-time recovery.

- Rajeev