The combined high-grade resource at Nhacutse and Poiombo is 256 million tonnes at 6% total heavy minerals, based on a 5% cut-off, within a wider 535Mt at 4.9% at Nhacutse and 325Mt at 4.8% at Poiombo, using a 4% cut-off, for a combined 860Mt at 4.9%.
MRG says both Nhacutse and Poiombo, which are 4km apart, demonstrate "exceptional homogeneity", and are ilmenite and titanomagnetite dominated, with 2% rutile and 1% zircon.
The 977Mt at 5% Koko Massava inferred resource is 4km to the northwest of Nhacutse, with an indicated 557Mt at 5.1%.
Koko Massava also contains a higher-grade 103Mt at 6.6%, using 5.5% cut-off grade.
All three deposits are about 40km from a proposed port at Chongoene.
MRG has also announced an exploration target for extensions to Nhacutse and Poiombo of 50-500Mt at 4.2-5.4%.
MRG was now in a position to think about potential mine start-up pit options for its wider Corridor Sands projects, chairman Andrew Van Der Zwan said.
"The three deposits are located in close proximity to each other, within good regional support infrastructure, enabling outstanding synergies for the company as it targets production at the site," he said.
The company is already undertaking a pit optimisation study into a potential high-grade start-up mine opportunity at Koko Massava.
More recently it has commissioned TZMI to run a market study of likely concentrate products from Corridor Sands.
The company completed a A$1.6 million placement at 0.8c in January to help fund its works, including its scoping study, and aircore drilling at the Marao licence.
MRG had $517,000 at the end of 2021.
Shares in the junior remained unchanged at 1.1c yesterday's close, valuing it at $19 million, about the same level as it has traded for six months, despite announcing three resource estimates.
