This was in a document seen by Reuters.
Baroka Platinum, part of the Baroka Tribal Mining business founded to help the impoverished Ga-Nkwana community, aims to take advantage of a sector shake-up as companies sell off underperforming and labour-intensive shafts to improve profitability after last year's five-month miners' strike.
[DATA AMS:Amplats] owns 49 per cent stake of the Bokoni mine, with the rest owned by its joint venture partner [DATA ATL:Atlatsa Resources].
The offer from Baroka also includes Amplats' 22.5 per cent indirect stake in Atlatsa, the document said.
(READ MORE: Amplats gets $385 mln offer for Bokoni mine stake)
The size of last month's offer to Amplats, a unit of global mining group Anglo American, is significantly lower than the 4.5 billion rand a source had said was submitted in December.
Amplats declined to comment on Wednesday and a Baroka spokesman was not immediately available to comment.
The proposed deal would give Baroka Platinum, which currently relies on royalty payments, its first production asset and allow it to funnel more money from the Bokoni mine to build schools, clinics and roads for the Ga-Nkwana community's 90,000 people.
The four-shaft mine produces 170,000 ounces of platinum group metals a year.
Baroka Platinum also plans to buy out Atlatsa's stake in Bokoni as soon as the deal with Amplats is sealed, a source with direct knowledge of the matter told Reuters.
The document seen by Reuters said that South Africa's state-owned pension fund, Public Investment Corporation, would fund part of the Bokoni deal in exchange for a stake in the mine, with further funding coming from local and international lenders.