Thanks for the quick answer, yes, I thought so, that I am doing something wrong, I keep trying.

I don't know the english names, I got a mining device, which produces the right stuff, when I pick it up, it is copper or stone or whatever. When I am using the robot arm, it is no more copper or stone but always coal.

Okay, it's not always coal, I am able to make iron, but when I try to make copper or stone by machine, I get coal (I can do it manually, but not automatically).
Where is my fault?