BHP chairman Ken MacKenzie has signalled the company could manage a NSW coal mine into retirement if a sale cannot be achieved, as an independent report found BHP’s action on climate change was lagging big peers like Rio Tinto.

The heavy focus on climate at BHP’s annual meeting came as Mr MacKenzie revealed the company was negotiating with the Australian government’s foreign investment review board (FIRB) over whether the Australian content rules that apply to the company should change once its dual-listed structure is unified.