Someone should really rewrite this book as a fairy story with no pretensions to representing real mining in 19th century Scotland. Nell, the child of the caverns, who has never seen the light of day evokes ancient stories of human children raised in underground kingdoms, and supernatural children adopted by humans. There is something bewitchingly and tantalizingly unreal about her, so long as you stick to seeing the story as fantasy. Harry, a born miner (almost literally) prefers life in the underground city founded by his father. After saving each others’ lives, he and Nell fall in love but he wants her to experience the world above before they commit. Meanwhile, her almost demonic guardian in the underworld will do anything to stop the marriage.
It’s very 19th century, but still… it would make a great Disney animation, or better yet, a Studio Ghibli.
Now, when we come to the supposedly realistic mining aspect of the book, I was less at ease with Verne's portrayal which was very, very idealistic compared to the reality. On top of that, it disturbed me not to be able to distinguish fact from fantasy in his little story without looking it up. I think that's just comes from being descended in part from northern (English) miners.
A note for Pratchett fans - you may be interested in the portrayal of the 'fireman', the original source for the dwarfish grags who are the villains of Raising Steam and appear in some of his other books. The firemen really existed, although not quite like this, I think.