Dragon's Fire by Anne McCaffrey

The McCaffreys' second fire-breathing collaboration (after 2003's Dragon's Kin) again proves why these fabled dragons still cast a spell. Pellar, a mute Apprentice Harper; Halla, a homeless girl; and Cristov, a miner's son, learn invaluable life lessons as the planet Pern prepares for the return of the deadly Red Star and its annihilating "Thread," which can only be destroyed by firestone-fueled dragonfire. But mining firestone is dangerous work, often carried out by children of disenfranchised criminals called the Shunned.