The violence that marked a strike by mineworkers in Marikana last year could not have been anticipated, the Farlam Commission of Inquiry heard on Wednesday.
"Nobody could have predicted that it would be the trend of those on strike to kill those working," National Union of Mineworkers (NUM) president Senzeni Zokwana said.
"We urged our members to go to work - we could not anticipate the violence... It was their right [to strike], but that right could not come at the expense of other workers' [rights]."
Zokwana was being cross-examined at the Rustenburg Civic Centre by Tshepiso Ramphile, representing families of murdered security guards at the mine when miners went on strike in August last year.
He told the inquiry the union encouraged workers to go to work, because the employer had the right to dismiss workers who embarked on an illegal strike.
If the situation was volatile the employer should have closed the mine, he added.
The union called for police back-up, not to negotiate, but to ensure law and order when miners went to work, because they feared for their lives, Zokwana said.
He said NUM had control of its own members, but had lost control when some members decided to join the strike and leave the union.
"We did not only lose control, we lost lives."
The inquiry heard that some miners were killed because they were leaders, not because they returned to work.
Zokwana said it was also the responsibility of the mine to ensure the safety of miners who went to work.
"The employer was supposed to render that protection [to workers going to work]."
The commission is probing the deaths of 44 people during an unprotected strike at Lonmin's Marikana mine.
On August 16, 34 striking mineworkers were shot dead and 78 injured when police opened fire while trying to disperse a group that had gathered on a hill near the mine.
Ten people, including two police officers and two security guards, were killed near the mine in the preceding week.
The inquiry continues.