There were a few raised eyebrows during Tim Flannery's speech yesterday, when the celebrated environmental scientist seemed to inadvertently substitute the word energy with "enemy".During his 20-minute speech Professor Flannery told the audience of mining professionals about the need for an evolving "enemy mix," before correcting himself to "energy mix".He later cited a US study which found the coal industry, in so far as it is used for power generation, kills about 21,000 people a year."I know having said that I'm likely to have put myself in the bad books of some of those in the room," he said."I don't want to do that, but I think the industry would be well served to recognise some of those costs."