THE BOURSE WHISPERER: Global Geoscience (ASX: GSC) unveiled additional development plan details for the company’s 100 per cent-owned Rhyolite Ridge lithium-boron project in Nevada, USA.
Global Geoscience explained the development flowsheet is based on findings from the recently completed first phase of a Pre-Feasibility Study (PFS) and comprises three key parts:
Sulphuric acid leach to extract lithium and boron from crushed rock into a Pregnant Leach Solution (PLS).
A step similar to acid leaching commonly used in oxide copper mines;
Evaporation and concentration of the PLS followed by crystallisation of boric acid.
Using mechanical evaporators, which result in a substantial water savings, the PLS is further concentrated. The boric acid product is then further refined by flotation and recrystallisation to produce high-purity boric acid. This step is broadly similar to the process used at Rio Tinto’s Boron Mine in California; and
Further evaporation and concentration of the PLS to allow for removal of remaining impurites via precipitation and ion exchange, followed by precipitation of lithium carbonate.
This step is very similar to the process used in lithium brine operations.
Global Geoscience detailed the Rhyolite Ridge site layout, saying it has been designed with the total surface disturbance footprint of the mine and related facilities being less than one square mile (640 acres), allowing the Federal Bureau of Land Management (BLM) to consider the project for the Environmental Assessment (EA) process, which the company indicated was less time consuming than the Environmental Impact Statement (EIS) process.
The site layout includes an open pit, process plant, haul roads, overburden storage, leach residue storage and salt storage.
No evaporation ponds or tailings dams are required.
“Our PFS work to date has provided a clear path to developing Rhyolite Ridge into a major, low-cost producer of lithium and boron in an environmentally sustainable manner,” Global Geoscience managing director Bernard Rowe said in the company’s announcement to the Australian Securities Exchange.
“We are prudently progressing Rhyolite Ridge toward production and remain on track to release the PFS outcomes in Q3 2018.”
Global Geoscience said it expects to complete the necessary environmental baseline studies by the end of Q3 2018.
Once this work is complete and it has submitted the Plan of Operations to the BLM, the BLM will make the determination regarding the Environment Assessment pathway forward for permitting and approval.