Uranium Boom Puts Sierra Pintada Back on the Map
An agreement worth more than $230 million between state-owned Dioxitek and U.S.-based Nano Nuclear Energy to finish the Formosa plant has reignited debate over Argentina's role in the nuclear fuel cycle. Although the project is being developed in the country's north, its implications also extend to Mendoza: the province is home to Sierra Pintada, one of Argentina's most significant historical uranium mining operations, currently suspended and undergoing environmental evaluation and remediation.
What is Sierra Pintada and why it's back on the agenda
Sierra Pintada, located in San Rafael department, was the last uranium facility to operate in the country: the San Rafael Mining-Processing Complex ceased production in 1997, following Argentina's broader shutdown of uranium mining operations during the 1990s. Since then, Argentine nuclear power plants have relied exclusively on imports for uranium supply.
The deposit is now overseen by the National Atomic Energy Commission (CNEA), which maintains it in the environmental evaluation and remediation phase, with no decision yet made to advance toward commercial exploitation. It is, along with projects in RĂo Negro, Chubut and Salta, one of the country's locations where identified uranium exists but lacks active productive development.
Sierra Pintada, uranium mine in Mendoza.
Mendoza's potential on a map beginning to shift
According to data from the Mendoza Chamber of Mining Companies, Argentina holds uranium reserves that could rank it among the world's leading producers, although most identified projects in the country—Sierra Pintada included—remain in evaluation and prospection stages, lacking the infrastructure and investment decisions necessary for full-scale exploitation.
That situation is beginning to change with renewed international interest in uranium. The agreement Dioxitek sealed with Nano Nuclear Energy for the Formosa plant—which plans to complete uranium dioxide (UO2) production and add a second phase to produce uranium hexafluoride (UF6), a key input for enrichment—does not by itself resolve the lack of domestic mining production, but it does reopen discussion on whether Argentina should resume producing its own uranium rather than continuing to import it.
Why Mendoza could return to focus
Argentina needs uranium, but it has not produced it since its mines closed nearly three decades ago. While Sierra Pintada remains in the remediation phase, the CNEA and private companies advance exploration at other deposits nationwide, such as Amarillo Grande and Cerro Solo in Patagonia, or Don Otto in Salta. In this context, any decision to restart uranium mining production in Argentina—driven by growing demand from domestic nuclear plants and by the export potential opened by the Formosa project—places Sierra Pintada once again as a mandatory precedent to review, as it is the only facility in the country with a track record of actual production.
Visit by provincial and national authorities to the Sierra Pintada mine.
Industry specialists emphasize that Argentina already has demonstrated technical capacity to work across the uranium chain: the country once enriched uranium and today retains conversion technology at the Pilcaniyeu Technology Complex in RĂo Negro. The question now taking shape, in light of the agreement with the U.S. company, is whether that know-how can once again translate into domestic mining production, with Sierra Pintada as one of the possible starting points on Mendoza's mineral map.