He envisions people living in big glass-carbon fiber domes on the surface, with additional areas mined out below the surface by robots for "industrial" uses.
Banks Group’s Highthorn coal mine would provide about 100 jobs during its five-year operation, with no mining activity planned within 500 metres of Druridge Bay beach.
He said he had intended to announce his retirement last year but chose to stay on while BHP dealt with the aftermath of the Samarco mine disaster in Brazil.