Bassman:
Too many Swedish hanging around lately 
Well, my procedure is:
1) glue styrofoam to the base with Vinyl glue (not acrylic, sorry). The typical “white” glue that becomes traparent as long as it cures.
2) let it rest until glue is completely cured.
3) shape styrofoam as a rock.
4) add some small pieces of rock to look more natural (optional step).
5) stuck/pin the mini to the base. This does not means always pin the mini to the base, just insert pins into the styrofoam.
I found that styrofoam is pretty resilient and the mini, even if a metal one, has never had any problem.
6) once the glue is cured, mix black primer and vinyl glue and prime the base (not the mini, it would cover too many details).
7) let them rest…
Results:
Orcs, the third sorcerer (staff one) and bull centaur standard bearer in my army blog.
https://discourse.chaos-dwarfs.com/t/8827