Across the Creek — Rosanne Hawke

Children in Aidan's town have mysteriously disappeared for years. When his friend Jenice disappears, Aidan goes in search of her. He crosses a forbidden creek, and with the help of a piskey named Raff, ventures into an abandoned mine. Here he discovers a strange world populated by mythical creatures who came to Australia with the first Cornish miners over 160 years earlier. Has he uncovered the secret of the missing children? And can he and Jenice escape the horrible spriggans and their fearsome dragaroo, or will they be trapped in the mines forever?