BHP Billiton Ltd. (BHP), the world's biggest mining company, has announced that its financial first half profit fell 5.5 percent. This is the first decrease in two years for the firm that is affected by rising costs, production disruptions and falling commodity prices.

We have delivered a robust result despite significant volatility, said Marius Kloppers, chief executive of the company. Sentiment changed from one month to another during that period, Kloppers added.

Net profit declined to $9.94 billion in the six months through December from $10.52 billion a year earlier, while revenue increased 9.7 percent to $37.48 billion from $34.17 billion, the company announced. The capacity for this organisation to redirect, adapt and steer things while keeping the overall cash investment and cash generated at relatively stable levels, we believe, is unparalleled in the industry, Kloppers continued.

The company's short-term outlook was mixed, but Kloppers said Australia's economic stability should offer protection in the long term. In the longer term, we expect the rate of growth in steelmaking raw materials demand, particularly in China, to decelerate as underlying economic growth rates revert to a more sustainable level, he said.

Iron ore remains BHP's key earnings driver and aluminum remains a drag on earnings, touching an underlying loss of $67 million.

BHP has plans to invest $80 billion in key divisions over five years. Also it would invest some $20 billion in its U.S. shale business, which it picked up in two large acquisitions in 2011, together worth $17 billion.