ioneer says it has signed a letter of intent (LOI) with Shell Canada Energy that will see the lithium-boron developer purchase up to 250,000 t/y of high-quality sulphur for its Rhyolite Ridge project in Nevada, USA.

This amount represents around 60% of the estimated annual sulphur requirement for the project, ioneer said.

“The signing of the LOI is one of the first steps to securing key reagents for the proposed acid leaching of the project’s lithium-boron Searlesite ore,” the company said, adding that both ioneer and Shell were working on turning the LOI into a binding supply agreement.

A prefeasibility study on Rhyolite Ridge, completed in October 2018, estimated production of 20,200 t/y of lithium carbonate and 173,000 t/y of boric acid, with production from 2021 and a 30-year mine life.

Managing Director of ioneer, Bernard Rowe, said: “Sulphur is the key input for the acid plant that is the heart of the proposed processing facility as it will provide the acid required for leaching the ore as well as all of the power and steam required to produce the lithium carbonate and boric acid at Rhyolite Ridge.”