Dear Mr. Campos,

Leaching can be used for different low-grade-large-tonnage U deposits. I have listed sometype  with countries where attempts have been made to recover uranium from:

phosphate:

Morocco, Tunisia, Egypt, Jordan, Israel, Turkey etc.

carbonaceous shales:

Sweden, USA

coal:

USA:

acidic igneous rocks:

Namibia, Greenland, Brazil

U-bearing Cu ores:

South Africa (Palabora), USA, Chile (Cu porphyries)

sea water:

Japan

saline brines:

USA (Searle's Lake)

If you take the mean values of U or maximum values you will get an idea what the grade is to come close to an economic use. Currently acidic igneous rocks and coal have agood potential.

> 100 ppm U3O8 should be in the ore. In-situ-leaching of marginal U ore lies around 25 % compared to the classical mining techniques

Harald G. Dill

Mrs. Campos,

Please find details for few substances with corresponding refs. The data in refs have shown more representative details for different chemical forms.