San Sebastian District
(3,450 HA), La Rioja
San Sebastian concession (3,450 Ha) in La Rioja. Excluded areas are outlined in blue. The main unit claimed is Permian carbonaceous, silty quartzite (tan colored on map).
The Isobel 15 concession of about 3,450 hectares is in the San Sebastian District of La Rioja. Several pre-existing claims are not included in the Isobel 15 concession. These are shown in Figure 3 as areas outlined in blue that mark the San Sebastian mine (mislocated on Mines Ministry maps) and other claims for feldspar. The San Sebastian mine was a major uranium mine in Argentina.
Known uranium occurs as veins and disseminations in Permian silty-quartzite. Uranium at the San Sebastian mine was originally mined underground but was finally bulk mined by open pit methods.
Uranium mineralization has been concentrated in carbon traps provided by the carbonaceous silty quartzite. Consequently, bulk-mineable deposits are the target of exploration in this area.