More angry shareholders have come forward with concerns about iron ore miner Grange Resources' plan to diversify into Melbourne's luxury real estate development sector.

Grange, which operates the Savage River iron ore mine in Tasmania, stunned investors in February when it revealed it had struck a joint venture with former AFL footballer Will Slade to develop apartments for downsizing Baby Boomers in the Melbourne council of Stonnington; home to some of Australia's richest suburbs, including Toorak and Kooyong.