Coronation Hill, South Alligator River, West Arnhem Region, Northern Territory, Australiai

Regional Level Types
Coronation Hill	Hill
South Alligator River	River
West Arnhem Region	Region
Northern Territory	Territory
Australia	Country

PGM & Gold mineralization in hillside reef.

Originally a uranium mine.

Coronation Hill is found in the Pine Creek Inlier, a east north-east elongated area, 400 x 150 kilometres, south and east of Darwin.

From the lowest is the Mundogie Sandstone of quartzite and conglomerate of the Mount Partridge Group. Then the East Alligator Group of the Koolpin Formation of siliceous and carbonaceous pelites and stromatolitic dolomite. This is overlain by a volcaniclastic unit. In turn this is overlain by two distinct sedimentary breccias, a break, then the Coronation Sandstone which consists of hematite altered pyroclastic and boulder conglomerate overlain by brown medium and coarse sandstone. Next is the Pul Pul Rhyolite of the El Sherana Group, a break, then the Kurrundie sandstone, then the Plum Tree Volcanics of the Edith River Group, all overlain by a thick layer of the Kombolgie Sandstone. There are also two prominent intrusives of altered quartz-feldspar porphyry, and an altered quartz diorite and granodiorite as plugs in the deposit area.

The gold and PGM/PGE mineralisation occurs in a north north-west trending elongated zone. The ore body is 250 metres long, 50-100 metres wide, dips steeply east, and south plunging. The tabular ore body averages 10 metres in thickness, usually within 250 metres of the surface but to a maximum of 400 metres, forming in fracturing zones. One source states mineralisation occurs in narrow quartz-carbonate-chlorite veins forming a series of sub vertical bodies that cut across existing lithological boundaries.

Another source states mineralisation is gold-PGM-selenides associated with pure gold and electrum, lead selenides, platinum-antimony and other rare precious metal combinations without Sulphides. Secondly, as gold-PGM-selenides sulphides similar to the first type, but with replacive pyrite within the intrusives.


The Coronation Hill uranium mine accessed a small sedimentary breccia lode, from a small pit near the top of the hill, producing 26 000 tonnes of ore, and some gold as a by-product at 10.4 g/t. Uranium mineralisation is associated with rhyolitic rocks near the surface as autunite and torbernite in a zone of strong fracturing. United Uranium mined the deposit from 1957-1964.

Drilling for precious metals in the 1980's, also identified a high grade uranium-gold deposit 120 metres below the old pit. It is found in complex folding and within brecciated chloritic tuffaceous siltstone, carbonaceous siltstone, and brecciated quartz-feldspar porphyry.

The proposal for another mine (gold and precious metals) here hit two hurdles. Firstly, being sited in the Kakadu National Park, it was opposed by conservationists. Secondly, it was also opposed by the local aboriginal tribe, who (correctly)believed the countryside around the mine made you sick, and that the mine would release the creator of the region, named Bula, from underground causing a catastrophe. In 1991, the Australian Government banned mining at Coronation Hill.
Placers derived from in-situ deposits located at Coronation Hill.(Albertson ref.)

Originally a uranium mine.

Other Regions, Features and Areas containing this locality

References