The world's largest miner, BHP Billiton ( BHP ) is up 2.16 pct or 77 cents to $36.47 while RIO Tinto ( RIO ) is up 3.72 pct or $2.34 to $64.91. MIDDAY REPORT (12pm AEDT) The Australian sharemarket has kicked off the new trading week in positive fashion, with the All Ordinaries index (XAO) up 1.9 pct or 78.8 pts to 4282.2. If inflation (CPI) remains subdued this Wednesday, it would increase the likelihood of a rate cut from our central bank if it deems it necessary over the next few months.