Australia’s Fortescue on Monday reported a $1 billion pre-tax impairment charge associated with its flagship magnetite growth project, while posting its lowest annual profit in three years amid a surprise senior-management overhaul. The world’s fourth-largest iron ore miner, which has been beset by senior management turnover over the past two years, earlier in the day announced the resignation of its metals division head and co-CEO Fiona Hick. Fortescue shares, up nearly 2.1% so far this year, fell as much as 6% to A$19.7 by 0200 GMT. A review of its assets at the