MELBOURNE, Aug 16 (Reuters) - BHP Billiton BHP.AX BLT.L reported a record $6.4 billion annual loss on Tuesday, hammered by a bad bet on shale, a dam disaster in Brazil and a commodities slump, but said it expects its free cash flow to more than double this year.
"While commodity prices are expected to remain low and volatile in the short to medium term, we are confident in the long-term outlook for our commodities, particularly oil and copper," Chief Executive Andrew Mackenzie said in a statement.
Even excluding $7.7 billion in writedowns and charges, underlying profit slumped 81 percent to $1.2 billion for the year to June 2016 from $6.4 billion a year ago, hit by weak iron ore, copper, coal, oil and gas prices.
The underlying profit was the weakest since the merger of BHP and Billiton in 2001, but better than analysts' expectations of around $1.1 billion.