Union men bury axe to take Rio TWO of the nation's biggest unions have signed a historic pact to try to start re-unionising Rio Tinto's iron ore operations, ending 30 years of bitter hostility that officials concede helped the mining giant create a non-union fortress in the Pilbara. The right-wing Australian Workers Union and the left-wing Construction Forestry Mining and Energy Union have signed an alliance aimed at jointly organising the 15,000-strong non-union workforce employed by Rio in northwest Australia.