"Why were you only in a meeting with the National Union of Mineworkers? I am not aware that you made any attempts to contact Amcu. Why didn't you?" asked Dumisa Ntsebeza, for the families of killed miners.
Ntsebeza was cross-examining Ramaphosa at the commission hearings in Pretoria, regarding his role as a Lonmin shareholder and non-executive director. Ramaphosa, a former NUM general secretary, said he did not have the contacts for the Association of Mineworkers and Construction Union. "I referred to Senzeni Zokwana (then NUM president), Frans Baleni (general-secretary) and James Motlatsi (founding president of NUM) because I know them and have worked with them," said Ramaphosa.
"I was not able to make any reference to any leader of Amcu because I do not have any details of them and I have not dealt with them."
Ntsebeza said as at August 2012, Lonmin and Ramaphosa believed that Amcu was behind the rock-drill operators' strike and the accompanying violence.
"Wearing your hat as a skilled negotiator, it was even more reason for you to engage them (Amcu). The fact that you didn't have Joseph Mathunjwa's cellphone number cannot be a reason. Lonmin had it," said Ntsebeza.
The commission, chaired by retired judge Ian Farlam, is investigating the deaths of 44 people during strike-related violence at Lonmin's platinum mining operations at Marikana, near Rustenburg in the North West, in August 2012.
Thirty-four people, mostly striking mineworkers, were shot dead in a clash with police, over 70 were wounded, and over 250 arrested on August 16, 2012. Police were apparently trying to disarm and disperse them.
In the preceding week, 10 people, including two policemen and two Lonmin security guards, were killed.
Ramaphosa said Amcu was denying involvement in the mines unrest at the time.
"This was what one could call a perfect storm that had evolved. Amcu was saying they are not involved so, in a way, abdicated. The CEO of Lonmin had taken ill and was not on the spot to negotiate.
"NUM itself was not really involved. We have heard that the workers had lost confidence in the NUM. As a non-executive director, not involved in the management of the company, I relied on the management team to deal with these matters," said Ramaphosa.
He said the Lonmin management had the responsibility to engage the unions.
Ntsebeza said that when Ramaphosa decided to step in and engage, he only contacted NUM-aligned people, excluding Amcu.
"We know that this was a strike for salaries and the demand was for management to engage with them. The quickest and most amicable way would have been for Lonmin management to address the strikers.
"You are an experienced negotiator, you know about give and take. When the rock drill operators asked to meet management, they were told that the mine would talk to the NUM. Were you told on the 15th August that Mr Mathunjwa had spoken to workers about going back to work?"
Ramaphosa said he saw Mathunjwa's visit either in newspapers or on television.
Ntsebeza said he would argue that Ramaphosa, as a former NUM general secretary, Lonmin shareholder and director, was uniquely placed to influence the warring parties to come to the negotiating table.
"I was just a non-executive director. I was not involved in the wage negotiations. The fact that I was former NUM general secretary was of no bearing in this.
"The fact that Shanduka was a shareholder was also of minimal bearing.
"We were just a minority shareholder amongst a body of bigger shareholders," he said.
Ntsebeza said nothing was preventing Ramaphosa from initiating negotiations, if he had decided to do.
Ramaphosa responded: "I should be flattered by the importance you seem to think I had, and the influence. It is simply not the case.
"When one is a non-executive director of a company, you deal with issues as they are presented to you by the management. You do not have the power that you seem to ascribe to a non-executive director."
Concluding his cross-examination, Ntsebeza said Ramaphosa, who once led black economic empowerment initiatives, had ironically procured a legal team "non-representative of the black economic empowerment".
"Your legal team is not reflective of an empowerment process. If you look at all the legal teams here, about 90 percent are non-racial," said Ntsebeza.
Ramaphosa complained: "Mr Chairman, does this have any relevance to the issue we are discussing now?"
Farlam said Ramaphosa could answer the question, if he wanted to.
The deputy president responded: "Message understood".
His legal team was led by lawyer David Unterhalter.
Ramaphosa will still be on the stand when the public hearings resume on Tuesday.