I found this book to be kind of choppy, and I had a hard time reading it aloud to the kids. So, that's the first thing.
Secondly, this book did not capture my kindergarten aged nephew's attention. He was almost totally bored by it, but I think that's partially because it was above his level of understanding. That's fine--some books that we read are aimed more at him, and others are aimed more at his older sister.
Thirdly, both kids asked me repeatedly who Nelson was. Nelson was a significant supporting character in the book. If they were not even able to keep track of the primary characters (there were three primaries), then something is amiss. They also had a very hard time following the plot of the story.
Finally, on the last page, my sister, who has a gift for cutting through the fog, said, "Geez! This book jumps around too much! What is going on?"
So this book is not so smooth. But the pictures were good. They were evocative of a mine. There was some good vocabulary in here, too. My nephew learned what slender means from this book, and there was even a new word to me in this story, too. The book also provided opportunities to discuss how kids once had to work alongside adults in some very scary and dangerous jobs. We didn't take advantage of those opportunities, but parents and teachers should know they're there. In the right hands, kids might be able to get some education from this book, but this isn't one that we particularly loved.