The UK-based NGO said security guards at the mine "swapped rubber projectiles with metal shot in their weapons, causing serious harm to local residents shot on the company's concession".
RAID, which released a report in November 2020 detailing human rights abuses at the London-listed miner's Williamson operation, said the information was uncovered as part of its ongoing investigation.
The report cited at least seven killings and 41 injuries of local residents by security personnel, with the most recent assault occuring in December 2020. Updated figures suggest the fatalities had increased to 10 with 50 injuries.
Responding to the allegations, Petra retierated it took the reports "extremely seriously" and had replaced Zenith Security - a third-party contractor employed at the mine - earlier this month.
In addition to RAID's reports, UK-based law form Leigh Day also filed claims in the High Court in September 2020 on behalf of 32 individuals alleging human rights violations by Petra and mine operator Williamson Diamonds.
Shares in the miner were up 6% following the news.
