Containment — Susan Kaye Quinn

The Mining Master of Thebe is all alone -- not counting the scavenger drones, foundry nanites, and magtread tractors buzzing across the tiny Jovian moon. When a spindly tower of rocks mysteriously appears at the pole, it's enough to vex the Mining Master's machine intelligence like dust trapped in a harvester joint. Reporting it could mean reassignment to the Outer Belt, but probing deeper into the mystery threatens to unlock something better left... contained. 

Containment  is a standalone short novella that takes place in the world of the Singularity novels.

Start the novel series with The Legacy Human (Singularity 1).