As Orc Fortress players might know, the Frostskald has an array of spells that can do both physical and cold damage.
I tried to apply the same sort of spells to improve the ice landmine and give it some real cold attacks. The problem is, that the frostbite effects depend on a series of spells working together -- hail to create some open wounds, splash with water to coat the victim, and then a cryoblast that flash freezes the water into ice coating. It's hard to get all these effects into the short lifespan (and short targeting range) of a landmine. If you just give it a bunch of attacks, it usually only has time to cast 1 or 2 of them before it dies, even if they're on fast short WAIT_PERIOD and CDI:FREE_ACTION. Especially, since the landmine attacks typically include a undirected dust explosion to finish things off.
My best attempt so far was to stagger a series of effects that kick in at different distances from the mine, and have staggered WAIT_PERIODS to encourage the mines to use more than one of them.
Still, most of the damage is done by the "hail" shrapnel and the following blast -- the only frost damage is when the cryovapor gets splashed on already gaping chest wounds, and noone dies of frostbite. I think the mine just doesn't provide the sustained exposure to the elements that frostbite requires.