The testwork, completed on 17 diamond drill core composites from across the deposit for a total of 427kg of material, confirmed spodumene as the dominant lithium mineral.
The tests achieved coarse grained pegmatite with concentrate grades consistently above 6% lithium oxide, the current industry standard, and recoveries up to 85% using heavy liquid separation (HLS) beneficiation at a coarse 6.3mm crush.
It also determined low contaminant levels in the coarse pegmatite concentrates, which were generally below the nominal 1% Fe2O3 preferred by customers.
At the same crush, fine grained pegmatite samples achieved HLS recoveries up to 60% and concentrate grades of 5.12-7.23% Li2O.
CEO Vincent Mascolo said the testwork demonstrated the project could deliver a premium product of plus-6% Li2O concentrates with low-level contaminants using simple gravity beneficiation.
"Further sighter flotation test-work at 106µm grind on fine pegmatite achieved exceptional recoveries up to 95.4% with concentrate grades between 4.2% to 6% Li2O, which is a a great initial result and demonstrates further optionality for a processing plant," he said.
He said this suggested a simple flowsheet design using crushing and gravity beneficiation to generate saleable concentrates with low capital intensity start-up, which could be further enhanced with a flotation cell to recover additional lithium credits at a later stage.
Like London-listed SolGold, IronRidge is part of DGR Global stable of companies.
ASX-listed, Nick Mather-led DGR holds 22% of IronRidge.
After spiking early in the day, IronRidge shares dropped 0.9% on Tuesday to 16.1p, up from 15.5p at the start of January.