Subterranean Rock Serpent

Rock Serpents are terrifying creatures that lurk deep underground, and they seem to have already built nests within the Mining Zone.
From the soldiers' casual talk, it's clear the Blackstone Legion has been plagued by them for a long time, yet they've never organized a true hunt. Instead, they lower the isolation gate without regard for the miners' safety, crudely sealing the Rock Serpent outside and releasing anesthesia smoke to keep the threat under control.
When the Rock Serpent enters an active phase, the Blackstone Legion even shuts the mines down outright.

As a force serving under the Duchy, the Blackstone Legion should be far from weak. Yet they would rather pay the enormous cost of sealing the mine than take real action.
So what's the truth here? Do they know they're incapable of eradicating the Rock Serpent, but keep mining greedily anyway—trading human lives for ore?
Or has the Squad already fallen into such hidden disorder that they can't even eliminate a single Rock Serpent?