Not sure if this has been brought up. The mines are not being staffed and I suspect that it is because I do not have enough unassigned laborers. A population breakdown of children, workers, assigned and not so I can get a better picture of how my labor force is spent and how many are truly available would answer this question.
Welcome to the forum. 
If you hover over the population on the top of the screen it gives you a breakdown of your villagers and also how many are eligible to work.
Also did you actually click on the mines to staff them? There is a minimum default figure, but if you want more then you need to click on the mine and staff them yourself.
I did not hover over that. I will see if it answers my questions. Yes, I did try to restaff the mines and they load for a minute then go back to not filled. Sometimes a few will be staffed sometimes none.