SYDNEY - BHP Billiton’s iron ore operations have been disrupted at the port of Tianjin after two massive explosions ripped through an industrial area in the northeast Chinese port city, the company said on Thursday. “We can confirm there was no damage to the iron ore discharging berths following the explosion at Tianjin port,” BHP said in a statement emailed to Reuters. “However shipments and port operations have been disrupted as a result and we are working with our customers to minimise any potential impact,” it said.