Deposit Synonyms

Mineral District

Mount Painter Uranium

Deposit Summary

U mineralisation in haematitic breccia. Total (Indicated + Inferred) = 51.0 Mt @ 615ppm for 31 400t U3O8 (300ppm cut off) (ASX Release, Marathon Resources, 2 September 2008).

Deposit Description

MOUNT GEE, uranium mineralisation in a continuous 10-20 m thick deposit (dependent on the cut off grade), and remained open in all directions. The host rocks were granite, syeno-granite, and syenite, containing magnetite, monazite, hematite and other minerals. The mineralisation was structurally controlled in particular along NE-trending, deep rooted basement fractures of regional significance. The fractures were part of a major tectonic deformation system, the Paralana Fault System (PFS). Mineralisation was propagated in tectonic-breccia-fracture zones corresponding to the activity of the PFS during the mineralising process. The matrix of tectonic-breccia-fracture zones contained predominantly hematite and chlorite and lesser sericite, quartz, chalcedony and carbonate. Microprobe and scanning electron microscope studies revealed that the dominant ore mineral was uraninite, and less frequently pitchblende. Some uraninite crystals were up to 5 mm. This suggested that increased space was created during structurally controlled extension, accompanied by the mineralising process, allowing growth of this size of crystal. Additionally Mount Gee was enriched in uranium silicate (coffinite) in certain zones, less frequently in brannerite, U-sorosilicate, and allanite. Monazite appeared to be U-free, and uranium mineralisation belonged to a different stage, confirming that the Mount Gee deposit (and PMS) was predominantly of epigenetic hydrothermal origin. Uranium carrying torbernite was seen as resulting from a later epigenetic stage process. Marathon Resources Limited inferred resource recalculated from old drilling and with new drilling undertaken was 57 million tonne @ 0.06% U3O8.(300 ppm cut off, 2006).

Discovery Year

? 1970

Commodities

Uranium, Uranium Oxide

Ore Minerals

Monazite, Uraninite

Gangue Minerals

Barite, Chlorite, Fluorite, Hematite, Pyrite

? Adelaide Rift Complex

Paralana Fault System (PFS), deeply seated NE-trending basement fracture system. Mineralisation was propagated in tectonic-breccia-fracture zones corresponding to activity of the PFS during mineralisation.