The system for finding resources is exhausting! I currently only have 2 geologists but to meet my current needs I will need about 4-6. I like to log into the game at least twice a day. Once in the morning and once after work. Within a day I can lose 2-4 marble 2-4 iron and approximately less than 1 coal mine. This does not count the the stone and copper that depletes.
It's physically impossible to get all the resources searched for as a casual gamer.
This is just an observation and would still like to give my thanks for this enjoyable game. Although, as a casual gamer I may not be able to keep pace with what it requires. As the game progresses in development, I hope that I will be able to meet all my gaming needs if I continue to log in only twice a day.