Under Fragile Stone by Oisin McGann
Volume II of The Archisan Tales
Taya and Lorkrin's shape-changing Myunan tribe faces an invasion by Noran, which is intent on mining the valuable iron ore from their sacred mountain, Absaleth. But the mountain is haunted and fights back with supernatural powers. Then a mine tunnel collapses and the miners are trapped. With them are Taya and Lorkrin's parents, Nayalla and Mirkrin, who had been searching for their unruly children.
Taya and Lorkrin are terrified for their parents. But help arrives in the form of their Uncle Emos. He and his friend Draegar know there is one chance for the trapped people -- another entrance to the caves far back in the mountain range. A rescue party sets out as the mountain starts to collapse in on itself.