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• Mining giant slashes first-half dividend
S&P had lowered BHP's credit rating in February and put it on negative watch to reflect sharply lower commodity price forecasts.
Mr Mackenzie said excess free cash flow will now be dedicated to value creation and shareholder returns, with strict adherence to BHP's capital allocation hierarchy.
BHP will first allocate maintenance capital before focusing on protecting its balance sheet, and then provide shareholder returns as per the new dividend policy.
"Finally, excess free cash flow will be used for additional returns to shareholders, organic and inorganic value creation projects, or used to strengthen our balance sheet," he said.
He also reiterated that BHP is close to reaching a settlement with Brazilian authorities over the Samarco dam disaster.
BHP is stil assessing the financial impact, but it is too early to say what the final cost may be.
In November, a massive spill of waste material in a dam collapse at the Samarco mine, which is co-owned by BHP and Vale, killed at least 17 people in what has been called the country's worst environmental disaster.
Brazil's federal attorney-general and public authorities in two states that were affected by the disaster, have asked the mining giants to set up a $US5 billion fund for clean-up costs and damages.
BHP has already outlined a $US1.12 billion provision against the Samarco business.
On Monday, ABC's Four Corners program said the mine's Fundao tailings dam was expanded despite a long history of problems.
Brazilian state police have alleged the disaster was partially caused by the mine ramping up production to offset the falling iron ore price.
Mr Mackenzie told the program he would wait for BHP's investigation to be completed, but Samarco responded, saying it had followed all the standards and conditions for operating the dam.