BHP has lost its landmark challenge to union “same job, same pay” claims for thousands of its in-house labour hire workers, in a decision the union says will cost the mining giant tens of millions of dollars a year.

The Fair Work Commission full bench late on Monday ruled that BHP’s subsidiary Operation Services was not an exempted service contractor and 2200 of its workers across three mines in Queensland’s Bowen Basin were covered by the Albanese government’s new labour hire laws.