Most are probably not aware of this, but there's a fair amount of AI code which does not reside in the bots, but in the weapons themselves.
For example, the standard UT Pulse Gun is the one which has the necessary AI code to "teach" a bot how to use and sustain the beam. By default a bot doesn't know how to handle a Pulse Gun.
In the same fashion, any weapons in this pack which are not just "shoot & kill" require at least some rudimentary level of AI built into them, so the bots use them how they are supposed to.
In the case of the Miner, since it's mostly a weapon to lay explosive traps to enemies rather than to engage directly, I made it so that they would randomly shoot the weapon sometimes in order to lay down some traps, to have yourself and the other bots/players to be careful and check their step, otherwise you get caught by an explosive surprise (which is the whole point).
The Miner AI code is not exactly brilliant by any means, it's mostly a rudimentary randomization where the bots will just shoot it in random directions at random times, and it may be the case where if this is the only weapon a pawn has (bot or monster), once it runs out of ammo the bot can no longer fire it (similar to the Redeemer problem you guys mentioned before).
But on the other hand, if the map is small enough, you may get caught by their mines they just placed.