BHP Billiton announced the shipment of its billionth ton of iron ore to China last week in a Shanghai ceremony attended by industry associations, partners and suppliers; the Melbourne, Australia-based BHP is the world’s biggest mining company.

CEO Andrew Mackenzie praised the milestone as key to one of the world’s greatest economic expansions. “BHP is proud of the role it helped play in China’s growth,” he said in a statement. “The rate of growth and demand for iron ore has been unprecedented.”

More than 20 years after its first iron ore shipment departed Port Hedland in 1973, BHP exported 100 million tons to the Chinese mainland, officials said. Shipments ramped up in the 12 years since; China represents nearly 50% of global steel production.

In all, BHP has invested $25 billion in mines, infrastructure and logistics in the Pilbara region of Western Australia, one of the world’s most iron ore-rich places, to meet this demand, according to company representatives.