Today I crushed every building group into one big reinforcement mine rebuilding colony expansion group to see if it is possible. I recorded a common mine, but didn't do settargcount(mapRobominer) yet. The strange thing was, it build a robo-miner and the mine. After that, there was no spare robo-miner left. But when I destroyed the mine, the AI built a new robo miner to rebuild the mine.