These can be recovered and sold to local ceramic and glass companies, said the AIM-listed explorer.
An initial mineral resource estimate at Grandao, a target within the Mina do Barroso licence, of 14.4Mt contains 4.79Mt of quartz and 6.11Mt of feldspar.
Other sites on the Mina do Barroso licence at NOA, Reservatorio, Pinheiro and Aldeia might also contain substantial amounts of the minerals.
Though lithium is the main target, these by-products have the potential to provide a significant additional income stream, Savannah said.
“Marketing studies concluded that prices for Mina do Barroso co-products could be significantly higher than reported in the 2018 Scoping Study, with feldspar at US$65-100/t vsUS$39/t, quartz at US$60-100/t vs US$33/t and a bulk tail at US$40-45/t.”
Glass and ceramics are two of the biggest global markets for feldspar and quartz.
David Archer, the chief executive, added the feldspar and quartz resource underlined the commercial appeal and robustness of Mina do Barroso.
"The co-products will be produced in a region where quarrying of feldspar and quartz is a traditional industry supplying vibrant ceramic and glass industries locally, nationally and more widely in the EU.
“They will not only help our bottom line but will help to reduce the volumes of materials that will need to be emplaced as waste on-site.
“Discussions are underway with potential offtake and JV partners to advance the co-product opportunity."