Can it really be a mere six months since Rio Tinto agreed to sell its birthright to Chinalco, losing its chairman-designate in the process? Indeed it can, and it shows how fast things change in the whacky world of commodities. In February, the directors panicked that the business might run out of cash; now they are signalling that they should be able to find $1.75 billion, or around $1.15 a share, for a dividend next year.