The ones with no limit do not have capability to OHK full health squad.
OHK means "one hit kill".
Not "walk over this field now please, trigger multiple mines and have last one kill all models".
If your squad is low on hp, that's tough luck.
I believe he's referring to tellers (and riegels).
I'm not sure what the damage on (individual) s-mines, RE mines, or the soviet defensive anti personnel mines are, but any that are 80 or higher are technically also capable of OHKing.
Finally, one could argue that booby traps and/or demos are mines. I wouldn't, but I imagine there's a discussion to be had there.