Why does Australia dominate seaborne iron ore supply despite China's huge reserves?

Why does Australia dominate seaborne iron ore supply despite China's huge reserves?
Australia holds roughly 58 billion tonnes of iron ore containing about 27 billion tonnes of iron, close to one-third of global reserves, with Pilbara's Hamersley deposits alone at 32 billion tonnes. Grades run near 62%, often up to 68%, and thick, shallow, continuous orebodies suit large-scale open-pit mining in a dry climate just 300 km from Port Hedland. That combination delivers a CFR cash cost near USD 34.5/t. China's ore averages about 34.5% Fe, sits deep underground, and needs beneficiation, pushing domestic CFR cash cost to roughly USD 82.8/t. Importing is simply cheaper than digging at home.