Interim results are due from UK power firm Drax ( LON:DRX ) and a trading statement from Talktalk Telecom Group Plc ( LON:TALK ) will likely also garner investor attentions. Perhaps, most notable though will be the latest operational update from the world's biggest miner, BHP Billiton plc ( LON:BLT ) should make interesting reading, with the group recently having named packaging executive Ken MacKenzie as its next chairman, a tricky job given calls from activist investor Elliott Management for strategic changes at the firm. MacKenzie, who was considered one of Australia's most successful chief executives in his 10 years running Amcor Ltd, will succeed current BHP chairman, Jac Nasser from September 1.