Uranium in Argentina

URANIUM IN ARGENTINA

Uranium Resources

Several geological types of uranium deposits have been discovered in Argentina. The current uranium identifies resources are over 35M lbs U3O8, although the CNEA (National Commission of Atomic Energy) estimates that there are close to 100M lbs U3O8.

Uranium exploration and a little mining was carried out from the mid-1950s but the last mine closed in 1997. Cumulative national production until then from open pit and heap leaching at seven mines was 2,509 tU. As a result of the systematic exploration, several types of deposits have been discovered since then: volcanic and caldera-related, sandstone-hosted, vein spatially related to granite (intragranitic and perigranitic) and surficial.

The deposits which have been objectives of the most important uranium exploitations are the ones that belong to the volcaniclastic type, which are localized in Permian formations associated with synsedimentary acid volcanism in the Sierra Pintada district (Mendoza province). The current identified resources are 9.7M lbs U. There are plans to reopen a mine in this area.

Several important uranium mineralisations have been identified in Cretaceous fluvial sandstones and conglomerates, among which the most relevant is the Cerro Solo deposit (Chubut province). The mineralized levels there are 0.5 - 6 meters wide and 50 – 130 meters deep. The current identified resources contain 15.4 million lbs U at 0.47% U.

Other subtypes of sandstone model have been studied. For example, the Don Otto deposit (Salta Province), located in the Salta Group Basin (Cretaceous - Tertiray), belongs to the tabular U-V subtype. This deposit was in operation from 1963 to 1980 and produced 594,000 lbs U. In 2007, CNEA reached an agreement with the government of Salta to reopen the mine. The roll front subtype can also be found in the Los Mogotes deposit (La Rioja Province).

Uranium mineralizations also exist in veins and disseminated episyenites (Cordoba and San Luis Provinces) and pedogenetic calcrete (Santa Cruz Province).

The existence of favourable basins and different uranium mineralization models provide promising conditions to develop new uranium resources. In this context, the uranium deposits related to continental sandstones appear as the most interesting exploration targets in the country.

Resuming Exploration Activity

The policy established by the National Government of Argentina in August 2006 related to resuming the Nuclear activity in the country, lead the CNEA trough the Exploration of Raw Materials Manager (ERMM) to establish working strategies for the next 10 years. These strategies together with the assignment of an adequate budget will contribute to define new uranium resources, which together with the already known ones, will be used to supply the requirements of Nuclear Power and Research Plants in the future. Thus, the ERMM is applying a policy of human resources hiring new personnel in order to count with the minimum necessary workforce to reach these tasks.

In Argentina known U resources are related to sedimentary, igneous and metamorphic environments. Considering the geology of the different regions, Argentina has been divided into 57 units in which the geological, geochemical, mineralogical and structural information is evaluated in order to estimate the uranium geological favorability of each unit. Prospection and exploration works are performed in the country by four exploration centers based in Salta (RN), Cordoba (R.Ce), Mendoza (R.Cu) and Trelew (RP). The works planned for each exploration center includes:

Northeast Region

Mina Franca Deposit: peri-granitic vein- type mineralization: 25% of surface exploration has been performed. Mineralized areas: Istataco and San Buenaventura correspond to an igneous-metamorphic environment, Sierra de Vaquería to a sedimentary one: Prospection stage.

Central Region

Mineralized areas: El Gallo: drilling stage and Donato: prospection stage, correspond to an igneous-metamorphic environment with intra and peri-granitic anomalies. Noya: prospection stage, sedimentary environment.

Cuyo Region

Mineralized area: Western Sierra Pintada: prospection stage, volcano-sedimentary environment. Neuquina Basin area: prospection stage. Uranium anomalies hosted by sedimentary deposits. This area is being tested for the application of in-situ leaching techniques (LIS).

Patagonia Region

East Pichiñán uranium District: it includes the Cerro Solo, El Ganso, Puesto Alvear, El Molino and Arroyo Perdido deposits hosted by sedimentary rocks. Exploration drilling and reserve evaluation are currently being developed in Cerro Solo, whereas exploration drilling is carried out in the other deposits. Laguna Colorada deposit: Corresponds to a volcano-sedimentary environment: an exploration-drilling program has been planned for this area. Mineralized areas Mirasol Norte, El Cruce, El Picahueso, La Salteada, El Curioso, Meseta Cuadrada, Sierra Cuadrada Norte and Sierra Cuadrada Sur, hosted by sedimentary rocks and Cerro Chivo, hosted by volcanosedimentary rocks. Different stages of surface exploration are being performed in these areas. Mineralized areas Laguna Sirven and Primavera, calcrete-type of mineralization, are being explored by means of trenches.

Fuel Cycle

A 150 t/yr mill complex and refinery producing uranium dioxide operated by Dioxitek, a CNEA subsidiary, is at Córdoba.

CNEA has a small conversion plant at Pilcaniyeu, near Bariloche, Rio Negro, with 60 t/yr capacity.

Enrichment services are currently imported from the USA. Over 1983-89, INVAP operated a small (20,000 SWU/yr) diffusion enrichment plant for CNEA at Pilcaniyeu. This was unreliable and produced very little low-enriched uranium. In August 2006, CNEA said it that it wanted to recommission the enrichment plant, using its own Sigma advanced diffusion enrichment technology which is said to be competitive. It was proposed to restart enrichment on a pilot scale in 2007 and work up to 3 million SWU/yr in three years, but progress is unknown. The main reason given was to keep Argentina within the circle of countries recognised as having the right to operate enrichment plants, and thereby support INVAP's commercial prospects internationally.

Production of fuel cladding is undertaken by CNEA subsidiaries. Fuel assemblies are supplied by CONAUR SA, also a CNEA subsidiary, located at the Ezeiza Centre near Buenos Aires. The fuel fabrication plant has a capacity of 150 t/yr for Atucha-type fuel and Candu fuel bundles.

Heavy water is produced by ENSI SE (Empresa Neuquina de Servicios de Ingeniería), which is jointly owned by CNEA and the Province of Neuquén where the 200 t/yr plant is located (at Arroyito). This was scaled to produce enough for Atucha 2 and the three following reactors, and so now has capacity for export.

There are no plans for reprocessing used fuel, though an experimental facility was run around in the early 1970s at Ezeiza.

(Sources: World Nuclear Association, International Atomic Energy Agency, CNEA)