Orosur's shares lost 11% yesterday in London as the junior also provided drilling results, saying three of five holes at Anza had intersected mineralisation, while two key areas remained off-limits.
A highlight was 14.85m at 1.6g/t gold, 1.08g/t silver and 0.79% zinc.
It said the other two holes were stratigraphic and not expected to intersect mineralisation, adding the number of drill rigs had been reduced from five to one and the focus redeployed to mapping activities.
Minera Monte Águila (MMA), a 50:50 JV between the gold majors, had elected to exercise its right to assume operatorship of Orosur's Anza project in September.
"The decision by our partners to take over operatorship of Anza was both positive and welcome, being testament to how two of the world's largest gold miners see the region," Orosur CEO Brad George said yesterday.
"The financial and technical resources that can now be brought to bear are without parallel and we look forward to them substantially ramping up activity."
MMA can earn 75% of Anza by spending US$30 million, paying $4 million to Orosur and delivering a feasibility study within 12 years under a 2018 agreement.
Orosur said it remained 100% owner of the licences and applications until MMA earnt its initial 51% interest in the project prior to September 6, 2022.
Two "major areas" of Anza remained at the application stage and were currently off-limits for exploration, Orosur noted.
It was hoping to accelerate the application process, including holding substantial public hearings, now COVID-19 was beginning to abate in the region.
Elsewhere, Orosur is continuing an exit from its historical Uruguay operations and recently entered a letter of intent to establish a tin JV in Brazil.
It had about US$5.7 million in cash last month.
About 90% of the company's liquidity resides in its London listing and it transferred its TSX listing this month to the TSX Venture Exchange, saying it would provide with operational efficiencies, lower costs and a reporting regime closer to that of the AIM market.
Orosur's London-quoted shares (AIM: OMI) are down 50% year-to-date.
They last traded at 13.25p, valuing it about GBP25 million.
