TORONTO (miningweekly.com) – Canadian uranium explorer U3O8 Corp this week announced that it had discovered an entirely new mineralised area - with the highest uranium/vanadium grades found to date - in the Laguna Salada district, in Chubut province, Argentina.
The TSX-listed company on Tuesday revealed the La Rosada discovery, which highlighted the district-scale potential for Laguna Salada-style uranium/vanadium mineralisation in near-surface, soft gravels in the semi-desert environment of central Chubut.
"This new discovery adds to our conviction that mineralisation in the Laguna Salada Deposit 1 and at La Rosada form part of a larger uranium district in which further exploration may lead to more discoveries and significant resource growth potential," company president and CEO Dr Richard Spencer said.
He added that Laguna Salada was advancing as a potential low-cost, near-term producer that could serve Argentina's growing nuclear reactor fleet that currently relied completely on imported uranium, as well as export opportunities to places such as the United Arab Emirates, Saudi Arabia, China, South Korea and Russia, with which Argentina has nuclear cooperation agreements.
“To this end, we are busy finalising a definitive agreement to partner with Petrominera Chubut, the provincial mining company, and completing a preliminary economic assessment - key milestones expected by the end of this year towards development of the Laguna Salada project,” he said.
The La Rosada discovery had the highest grades encountered to date in the soft, free-digging gravels in the Laguna Salada district, and for the first time, U3O8 had identified uranium/vanadium mineralisation in the adjacent basement rocks, which may be a source of the mineralisation in the gravel.
Vertical channel samples through the gravel had a weighted average grade of 1 500 parts per million (ppm) uranium oxide (U3O8) and 780 ppm vanadium (V2O5) from a layer of gravel about 0.7 m thick, starting at an average depth of 0.3 m below the surface.
This average grade was from two areas of gravel, totalling 3.2 km2 in extent, that were perched on Jurassic basement strata. The highest grade encountered in the gravel at La Rosada was 11 780 ppm (1.1%) U3O8 and 5 168 ppm (0.5%) V2O5 in a 0.4-m-thick horizontal layer.
The company said the near-surface mineralisation at La Rosada was typical of the Laguna Salada deposit where the uranium/vanadium occurs in the fine sand between the pebbles in soft gravel that could be amenable to beneficiation by screening, which removes the pebbles and coarse sand.
Screening of Laguna Salada gravels concentrated over 90% of its uranium in about 10% of the gravel's original mass, resulting in a 10-to-11-times increase of grade in the fine material. Gravel in the Laguna Salada district is unconsolidated and is amenable to low-cost continuous mining that involves no blasting or crushing.
Mineralisation is expected to continue in the gravels beneath the sand cover to the south of the La Rosada discovery – and exploration would now shift to that area.
Rock-chip samples from the Jurassic basement rocks next to the gravel terrace at La Rosada had defined potentially significant mineralisation with elevated uranium grades ranging from about 100 ppm U3O8 to more than 7 900 ppm U3O8.
This hard-rock uranium required systematic trenching to establish its scale and resource potential as a target in its own right, and might be a source for some of the uranium and vanadium in the adjacent soft, pebbly gravels, the company said.
U3O8 Corp is also focused on its flagship Berlin deposit, in Colombia, with a preliminary economic assessment having indicated thye project potentially being a zero cash-cost uranium producer owing to by-product revenues.