Industrial action at BHP’s Port Hedland iron ore operations intensified Sunday as worker participation grew to 150 people. Members of three unions are conducting the first major strike at the Western Australian facility since 2000. The escalation follows an initial 24-hour ship loading ban that commenced Saturday morning.

Port Hedland is the world’s largest iron ore export terminal. BHP transports approximately $80 million worth of iron ore through the hub every day. While BHP has activated contingency plans to maintain vessel loading, a sustained disruption threatens global supplies.

The labor groups are seeking a new four-year workplace agreement. Formal negotiations between BHP and the unions are scheduled to resume on August 18.