The AIM-listed group holds 17.02m shares in Jupiter, which posted after tax profits of A$95mln (A$138mln) in the year to 29 February.
Jupiter owns a 49.9% stake in the Tshipi manganese mine in the Northern Cape.
The South African Government has authorised open pit mines including Jupiter to resume full production from 1 May after a coronavirus lockdown.
Andrew Bell, Red Rock’s chairman, said: “Jupiter has maintained a high sales level at its 49.9% owned Tshipi manganese mine, with 3.41m tons sold, and is conducting a feasibility study on expansion to a 4.5m ton production operation
“Current manganese ore prices of $6.31 per DMTU FOB Port Elizabeth owe something to Covid-19-related shutdowns, though the price was already recovered from low end-2019 levels before the virus hit.
“Jupiter has shown its capacity to make money even at low manganese prices, so if anything like current prices can be maintained this will be positive for prospects.
“At the closing price of A$0.27, the dividend yield for the year just ended is 17.6%, reflecting the high payout policy of the company”.
Red Rock’s holding is worth A$4.59mln (£2.4mln) at a price of A$0.27 per share.