So cool that you made an RTS game. I am super keen to try my hand at an RTS next. I found it a bit confusing though. I think it would feel a lot cleaner if the workers maintained their tasks. Then you could destroy the resource nodes quickly and this would create the need for the mining facilities to be built more and more as your workers have to travel further and further out.
Also found the building placement system a little confusing because I wasn't aware that I was in "building placement mode" at times and wondered why I couldn't select anything.
But really cool, good job!