So far, a follow-up sampling program at Samba has helped define three high potential areas - Samba North, Samba West and Samba South, the company said.
The newly discovered rare earth and phosphate zone was found within Samba North, where an analysis of the best phosphate results of up to 26% revealed a combined mineralization with total rare earth elements (NYSEMKT:REE) of up to 0.5%.
The Samba North area is characterized by an elongated, north-east oriented ridge that reaches up to 250 metres in elevation and has approximate dimensions of 7 by 1.5 kilometres.
The results obtained to date are located in the northern limit of the ridge, with mineralization open laterally along the ridge.
Some channel sample highlights from this area include 26.34% P2O5 and 0.44% total rarth earth oxide (TREO) in one sample, and 21.1% P2O5 and 0.47% TREO in an another.
The company said the bordering area of the Samba North ridge is a siltstone with phosphate grades of up to 5%, based on channel samples of 1 metre taken at surface from outcrops.
The area is relatively flat and the mineralization is open to depth, Eagle Star added.
Phosphorite layers occur within the siltstone packages at the site and host high-grade phosphate and REE mineralization.
Further work at Samba North will include detailed mapping to estimate the thickness of each rock type package and map the phosphorite layers.
Additional sampling of the phosphorite layers and of the sandstone will be carried out to verify the solubility of the phosphate, the company said.
Meanwhile, a total of 28 pulps were selected to run rare earth element analysis, with results still pending.
At the Samba South and West areas, the company said the Samba South zone has returned chip samples to date of up to 4.8% P2O5, with rare earth results pending.
Eagle Star said that at the Samba West area, phosphorite lenses are seen to be more restricted, but they still returned values of up to 17% P2O5. Rare earth results are also pending.
In order to further test the potential of these areas, mapping and additional sampling is required, said the company, and will be carried out once the Samba North work program is finished.
The sampling program has helped the company find the most promising areas to be drill tested, with the REE mineralization presenting an additional "attractive" opportunity to be developed, Eagle Star said.
REE deposits associated with Paleo-placers, like the Bold Mountain in the USA and the Elliot Lake in Canada, are typically formed by consolidated and cemented rock types, similar to the ones that occur at Samba North, the company noted.
"The work performed at Samba to date has yet again delivered excellent results," said Eagle Star board member, Dr. Guimarães Campos.
"In addition to proving the presence of P2O5 at potentially large volumes in Samba, we were also pleasantly surprised with the strong REE sample results.
"The combination of these minerals with phosphate could ultimately shape Samba into a unique mining opportunity beyond our initial expectations."
The company is awaiting official permits to allow for more detailed exploration, including drilling at Samba.
The 109,285-hectare Samba property, which consists of 60 mineral claims, is located near the cities of Valenca and Sao Jose do Peixe in Brazil, and near Eagle Star's Ruth phosphate project.
The asset is also located near potential future end-markets, including the Balsas and Bom Jesus agricultural centres - which are home to a large soy growing industry with production of over 2.3 million tonnes of beans annually.
Earlier this month, Eagle Star said it had found a mineralized phosphate package of at least 7 metres in thickness within the Canabrava block at its Ruth project in Brazil.
The mineralization, which extends laterally over 13 kilometers, was identified through follow-up sampling of the best results obtained in a regional reconnaissance program announced last year.
The package is still open at depth, Eagle Star said, with its team currently in the process of outlining drill targets and detailing a systematic drilling campaign that will determine the depth extent.
Eagle Star Minerals Corp. is focused on the agro-mineral properties in Brazil. In February, the junior explorer refocused its strategy on phosphate exploration in Brazil. Phosphates are a key ingredient for inorganic fertilizer.