BHP Billiton's (BHP) new CEO will take over as the miner suffers its worst profit drop in more than a decade, slumping 58% in H1 to $4.2B. Revenues fell 14%. Says it cut $944M in costs over the past half year, but did not outline a broader target for cost cuts. Believes global economy will strengthen over the next 12 months, providing support for commodities demand and pricing. Shares -2.5% premarket.