At 0036 GMT, Fortescue was 7 percent lower at A$1.78.
Feeling the effect of weak iron ore prices, rival miner Rio Tinto saw net profit drop 82 percent in the last half-year
Analysts also expect BHP Billiton to unveil a 43 percent fall in underlying attributable profit to $7.73 billion in its financial results released on Aug. 25, according to Thomson Reuters I/B/E/S.
Read MoreIron ore's bull run is merely technical
Fortescue, sold its ore for an average of only $52 per ton in the half-year to June 30 versus $82 in the year earlier period.
The benchmark spot price for high-grade ore opened in January at $71.20 a ton and finished on June 30 at $59.30, down 17 percent.
However, Fortescue must sell its ore at a roughly 15 percent discount to the benchmark due to its lower iron content.
Power in July called an end to expansion work at Fortescue's Australian mines, saying more than enough ore was being mined to meet global demand. At that time, Power criticized larger Australian miners Rio Tinto and BHP for ramping up output despite soft demand and slumping prices, despite his own company lifting shipments 33 percent in fiscal 2015 before calling a halt.
For the full fiscal year, Fortescue's $316 million was a far cry from the $2.7 billion it reported the previous year.
Read MoreAsian stocks tumble again to multi-month lows
The downturn in mining has had far-reaching implications for the sector. Mining services group UGL on Monday posted a A$236.4 million net loss for the year to June 30, compared with a $62.1 million net profit the year before.
Boart Longyear, another mining services company, announced its chief executive was stepping down after its half-year net losses worsened to $152.3 million from a $142.8 million loss in the previous corresponding period.
Fears of a China-led global economic slowdown drove Wall Street to its steepest one-day drop in nearly four years on Friday.