Global mining giant BHP Billiton Tuesday posted an 86.2 percent slump in annual net profit despite slashing costs, as a collapse in Chinese demand for key raw materials hit hard.

The US$1.91 billion result in the 12 months to June 30 compared to US$13.83 billion a year earlier, as the prices of key commodities, including iron ore, coal and oil, plunged over the year.

Underlying earnings -- which exclude one-off writedowns -- were down 52 percent to US$6.4 billion.