Did the Fire Nation support child labour?

Question

I was recently watching short video clips of Avatar: The Last Airbender when I was watching a certain scene from a certain episode where Aang goes to a Fire nation school. This is the dialogue from when Aang is having a meeting with the principal in charge:

Principal: "Thankyou for coming, Mr and Mrs....."

Sokka: "Fire, Wang Fire, This is my wife Saphire"

Katara: "Saphire Fire"

Principal: "Mr and Mrs Fire, Your son has been enrolled here for two days and he is already causing problems. Hes argued with his history teacher, disrupted music class and ruffed up my star pupil"

Katara: "My goodness, that doesn't sound like our Kuzon"

Principal: "That's what any mother would say ma'am, none the less you are forewarned if he acts up one more time I'll have him sent to a reform school, by which I mean the coal mines"

I want you took look at the words in the last sentence. Is this just a hyperbole or is this actually something they would do. I was thinking this was a hyperbole but if you think about it there are many things that would indicate that this could be true due to the fact that.....

1. The Fire nation were at war with the Earth Kingdom and the Water Tribes (mainly only the north) as the Southern Water Tribe benders were killed due to imprisonment from the first attacks from the Sea Ravens.
2. The Fire nations armies relies on Coal, including their war machines and big war ships.
3. Times would have been harsh, and money would have been a big problem so it would be logical

So based of this and information on the Fire lord at the time and the Fire nation in general, would it be plausible (if any) that the Fire nation supported child labour?

Answer 1

During the show, we never see an actual coal mine, just the mining village where Team Avatar meets Haru.

Located within the Earth Kingdom, but occupied/controlled by the Fire Nation, the village is just short of a prison.

The youngest person we see, who seems to work in the mines is Haru, who is 16. Whether or not anyone younger than him works in the mines is left unclear, but I would gather that in such a town, any adolescents or older would likely be working to some degree.