BHP Billiton Ltd., the world’s biggest mining company, reported a 5.5 percent drop in first- half profit, the first decline since 2009, driven by a decline in base metals earnings.

Net income was $9.9 billion in the six months ended Dec. 31, from $10.5 billion, a year earlier, the Melbourne-based company said today in a statement. That compares with the $10 billion average estimate of seven analysts surveyed by Bloomberg.

Metal prices in London declined 20 percent in the half on reduced demand in Europe and slowing industrial production in China, the world’s largest metals buyer. Chief Executive Officer Marius Kloppers has committed to spending $80 billion over the next five years to boost output of iron ore, copper and coal.

“The biggest hit comes from base metals,” Lee Bowers, a resources analyst at Macquarie Group Ltd. in Sydney, said in a phone interview before the results.

BHP shares fell 0.8 percent to A$37.90 at the close of trading in Sydney yesterday, compared with a 0.5 decline in the benchmark S&P/ASX 200 Index.

BHP has 16 “buy” and 4 “hold” recommendations, according to data compiled by Bloomberg. The company may post full-year net income of $20.6 billion in fiscal 2012, according to the median of 22 estimates compiled by Bloomberg.