A LEAKED internal memo, written by a high ranking BHP executive, warned mine site managers the ongoing enterprise agreement negotiations battle was "likely to get tougher before it is over".
BHP Billiton's coal chief executive Marcus Randolph thanked the company's senior executives for their efforts during the 16-month dispute and wrote "this is the fight we had to have".
"Being asked to yield on something that we cannot accept means this battle is likely to get tougher before it is over," he wrote.
"This will be hard for you, for the people you lead and for your families.
"This is stressful and I suspect many of you (and your families) have been the victims of personal abuse."
A spokeswoman yesterday confirmed the authenticity of the email.
CFMEU president Tony Maher said the email proved the company was not committed to bargaining in good faith with the Single Bargaining Unit, which comprised the CFMEU, AMWU and ETU, for the purpose of negotiations.
He referred to the statement made by Mr Randolph, which said the outstanding issues with the unions "are not negotiable; not now, not next month and not next year".
"This shows the company went in with a strategy to purposely ignore its workforce, to enter negotiations with no intention whatsoever of listening to employee concerns," Mr Maher said. "The executive even puts 'management's ability to manage' in inverted commas because he knows it's just their spin on the company hanging on to Work Choices."
Mr Maher said he had never seen as determined a workforce as that across the Bowen Basin: just two people voted against the industrial action, with more than 2500 in favour.