The news comes just days after the junior said Barrick had begun initial drilling at the pair's 1,894sq.km JV on the Ngayu belt, which lies about 220km south of the Barrick-operated Kibali gold mine.
Barrick is moving towards earning 65% of that joint venture under a 2016 agreement, where Loncor has described the aim as "looking for the next Kibali".
Loncor said the new deal between Barrick and its 76.29%-owned subsidiary was similar to the other JV terms, with Barrick to manage and fund all exploration of the JV properties until the completion of a pre-feasibility study.
Once a JV committee determined to move ahead with a full feasibility study, Barrick would gain 65% subject to the DRC's free-carried interest requirements.
"We are pleased to see Barrick's confidence in the Ngayu gold belt continue to grow," Loncor CEO Arnold Kondrat said yesterday.
"This new Barrick JV further consolidates the control of the Ngayu gold belt by Loncor and Barrick as partners."
Loncor also has the Makapela gold deposit and a 76.29% interest in the 2.5 million ounce Imbo project, both in the Ngayu belt.
Dual-listed Resolute Mining holds 26% of Loncor.
Kondrat increased his stake to 28.45% in a February placement at C40c per share, which raised $2.4 million.
Loncor shares (TSX: LN) have ranged between 19-88c over the past year and closed unchanged yesterday at 58c, valuing it at $59.3 million (US$43.4 million).
Barrick closed up 0.69% in Toronto to $35.05, capitalising it at $62.3 billion (US$45.6 billion).