"Let me tell you why [these mines] should be put up for public auction. Let me give you the logic. If government takes over liability, that is not nationalisation," he told reporters on the sidelines of an ANC national executive committee (NEC) meeting in Pretoria on Thursday.
"We are inheriting liabilities from capitalists who have made money and want to run away from responsibility that goes with the end of life of a mine."
The African National Congress rejected the idea of wholesale nationalisation at its elective conference in Mangaung in December.
Mantashe was responding to a statement by the Association of Mineworkers and Construction Union (Amcu) on Thursday that the government should nationalise Anglo American Platinum (Amplats) if it continued with the proposed retrenchment of 14 000 workers.
"If Anglo persists with the retrenchments, it's a window for government to take those mines and nationalise them," Amcu president Joseph Mathunjwa said.
The loss of 14 000 jobs
Amplats announced this week it planned to stop production at four of its shafts in Rustenburg, which could result in the loss of 14 000 jobs, and to sell a mine which was considered unsustainable.
As a result, workers embarked on a strike at Amplats mines and refused to go underground on Tuesday.
The Amplats announcement came after Harmony Gold said it was suspending operations at its Kusasalethu mine in Carletonville, to review operations after several illegal strikes.
Mantashe said the ANC had made a proposal to the mineral resources department that shafts which had become unsustainable, or been "mothballed", be put up for auction.
"[The proposal was] that mines with mothball shafts must actually give up their licences for those shafts and those shafts must be put up for public auction for companies that want to operate."
Retrenchment is 'mischievous'
Mantashe called the retrenchments insensitive.
"The question of Amplats destroying 14 000 jobs at a go is actually mischievous and insensitive."
The ANC's NEC would elect its national working committee over the next two days.
"There are two issues [to be addressed during the meeting]: political overview and the election of the national working committee," he said.
The meeting in Pretoria was a continuance of the NEC's first meeting in Durban, on January 11.
Mantashe said the ANC would hold its national lekgotla from January 30 to February 2.
"This is the mid-term report about our performance in respect of the five priority areas."
The lekgotla would be held to "streamline" the implementation of the Mangaung conference resolutions. – Sapa