Exploration to Date

Previous mineral exploration within the Chile Norte region has mainly involved prospecting for copper and uranium (Bobenreith, 1982). In addition, two salt mines are currently operating on the lake surface. Essex Minerals Company Chile, 1978-1980, detected uranium via airborne radiometry and prospecting along the south-eastern and western edges of Chile Norte. Uranium occurrences comprise carnotite mineralisation impregnated in the salt crusts of the Salar, largely coincident with the trace of the Salar Grande fault system.

Uranium exploration undertaken by Essex Minerals between 1977 and 1981, and reported by CCHEN with consent by Essex Minerals, identified ten anomalies over two sections; 5km and 17.5km in extent (Bobenreith, 1982). The preliminary radiometric aerial survey was followed up by a limited program of ground mapping, radiometry, trenching and sampling. The uranium assays from trench and pit samples ranged between 2.3kg/t and 8.2 kg/t, with gamma radiometry up to 7.000 cps (Bobenreith, 1982). The uranium mineralisation occurs over distances ranging from 500 to 2,000m, forming a mineralised anomalous area 17.5km long and 0.3 to 1.5 km wide (Bobenreith, 1982). Some of these occurrences have been explored with trenches and shallow (~1m deep) pits.

CCHEN compiled this earlier exploration data and conducted minor check work. CCHEN rated Chile Norte as the second largest uranium project in Chile (Productora rated as the largest) following a review of over 80 confirmed uranium prospects that have been identified in the country to date (CCHEN Presentation, Nov 2008).

Metallurgical studies by Essex Minerals on the surface-related uranium material indicate that with sodium carbonate leaching 90% of the uranium is released and with sulphuric acid 97% is achieved (Bobenreith, 1982). Further studies by CCHEN using sea water obtained a pre-concentrate of 2000ppm U, 64.5ppm La, 434ppm Ce, 37.7ppm Yb and 24ppm Lu, which when attacked by an acid leach recovered 97.5% of the uranium (Bobenrith, 1982).

The majority of historical work undertaken for uranium at the Chile Norte project lies over land which is not contained within Hot Chili’s land position.

In July 2009, Hot Chili engaged Jigsaw Geoscience to conduct a field reconnaissance review of the Chile Norte project. Field multi-element sampling from this visit yielded the following results:

• Old uranium trenches yielded significantly anomalous uranium (U) assays ranging from 40ppm U to 5710ppm U. Other anomalous elements associated with uranium included vanadium (V - 14ppm to 1310ppm) and strontium (Sr – 71ppm to 3690 ppm).
• Salt crusts over fault zones on the western splay of the Salar Grande fault system returned anomalous uranium values varying between 40ppm U to 320ppm U.
• Sulphur levels were generally elevated in most samples (average assay of 3.16% S – almost twice crustal abundance).
• Copper assays from various prospecting pits and inactive copper mines returned anomalous copper assays (range: 0.37% Cu to 5.48% Cu).

Exploration work undertaken by Hot Chili has confirmed the presence of a strike extensive zone of near-surface uranium mineralisation that is interpreted to extend and be concealed under shallow colluvial cover through Hot Chili’s land positions. This work mainly comprised ground truthing, confirmation sampling of trench material and ground scintillometer readings.

Structural damage zones associated with restrictional jogs and fault intersections have been identified as primary trap sites for the concentration of poly-metallic bearing fluids. Several areas of significant copper-gold-cobalt mineralisation are also identified within Hot Chili and CODELCO’s land position that will warrant follow-up exploration.