Refinishing Fireslate

[w802h]

Hi FOG,

I'm going to re-finish fireslate kitchen countertops later this month.  They aren't in awful shape, but the homeowner wants another coat of tung oil applied.  I have no idea what grit or media I should use for prep.  I have 80x133 and 6" sanders.  Any insights are welcomed and appreciated.

Thanks!

 

[Sanderxpander]

[DELETED]
Excuse my awful advice from before, based on the mention of "oiling" I assumed fireslate to be some kind of wood, I now realize it's some kind of stone/concrete.

 

[w802h]

Well, it's not something I've run across before either!  I'm leaning toward Vlies for prep.