The Dragon of Cripple Creek by Troy Howell is a book about a dragon guarding gold in an Old West mine and the girl who discovers him and his dragon gold. There is also an interesting sibling story thrown in.
Synopsis (from Goodreads):
When Kat and her father and brother visit the Mollie Kathleen, an old gold mine now open for tours by the busload, Kat gets lost from the group and falls down a shaft, where she discovers an awe-inspiring world of fantasy come to life. She meets an ancient dragon—the last of his kind—and discovers a secret about the gold that litters the creature's den and why dragons throughout time have hoarded the sparkling treasure. The dragon helps Kat escape the endless caverns, but not before Kat greedily takes a piece of gold for herself. Feeling guilty, Kat decides to return it, but before she can do this she drops it in front of a group of visitors, and a media frenzy ensues. Soon the mining town is filled with gold seekers. In order to save the dragon and his gold, Kat and her brother must venture back into the mine to warn him. But will they get there in time?
The novel has a lot going for it: adventure, siblings working together, a dragon. Most of it works very well too. Kat is a fun heroine, one who makes ridiculously bad decisions, but you can't help loving at the same time. Her brother is one of those characters I love, apparently lazy and a joker he is actually covering up a brilliant mind for trickery and subterfuge. I love the setting of the Old West tourist town too. Plus there's a dragon. All stories are improved when you add in a dragon. Especially one who knows so many big words. The book does suffer from being too long and getting lost in its own wordiness in the middle. Still it is a fun read for any one who likes a good dragon story or tall tale.