BHP’s plan to divest the South African assets of its target Anglo American are key to the strategy behind the proposed takeover and is expected to be a part of any revised offer, investors briefed on the miner’s thinking said. The “Big Australian” was rebuffed by its smaller rival on April 26 after submitting a $39-billion takeover proposal, in a plan seen as complex because it required Anglo to offload its shares in Kumba Iron Ore and Anglo American Platinum (Amplats) to Anglo American’s shareholders before any deal took place.