The Maud Creek goldfield, which includes the historic Maud Creek mine and the Gold Creek deposit, is located about ~20 km east of Katherine.
The Gold Creek deposit was discovered in 1985 and is located about ~1 km west of the old mine workings. The historic Maud Creek mine was exploited from 1890 to 1892 and 1932 to 1940, to produce 16.8 kg of gold (Cottle 1937; Crohn 1961; Walpole et aI., 1968).
The Gold Creek deposit is hosted by quartz-haematite breccia sub-cropping over ~1 km long, north-south striking interval. Unlike the lodes at Maud Creek, which are hosted within the Maud Dolerite body, those at the Gold Creek deposit are within the of the Palaeoproterozoic Finnis River Group of the Pine Creek Geosyncline. The Pine Creek Orogen covers an area of ~47 500 km2 and comprises a thick (>4 km) succession of Palaeoproterozoic 2200 to 1870 Ma supracrustal carbonate and carbonaceous sedimentary and volcanic rocks, unconformably overlying Neoarchaean ~2670 to 2500 Ma granitic and gneissic basement. This succession was subjected to regional metamorphism and deformation of varying grades and intensities in different parts of the orogen in the period ~1867 to 1850 Ma, and syn to post-tectonic granite emplacement at ~1830 to 1800 Ma (Ahmad and Hollis, 2013).
The Finnis River Group in the Central Domain is subdivided into the Burrell Creek and Tollis formations. The Burrell Creek Formation is composed of interbedded phyllite, slate, mudstone, feldspathic greywacke and minor pebble conglomerate. The overlying Tollis Formation, that hosts the Gold Creek deposit, has a limited aerial extent, and comprises a succession of interbedded mudstone, slate, metagreywacke and minor felsic volcaniclastic shale that conformably overlies the Burrell Creek Formation. Detrital zircon U-Pb geochronology on a sample from the Katherine Gorge Road yielded a conservative maximum depositional age of 1868±5 Ma (Worden et aI., 2008; Ahmad and Hollis, 2013). The Dorothy Volcanic Member comprise a ~200 m thick succession of basaltic lavas, pyroclastic rocks and tuffaceous sedimentary rocks that overlie and are folded into the Burrell Creek Formation and are tentatively included within the Finniss River Group (Walpole et aI., 1968).
The Maud Dolerite, host to the is exposed in a small area at Maud Creek. It is a massive, medium- to coarse-grained to gabbroic, dark-grey quartz dolerite (Kruse et al., 1994). The dolerite intrudes the Tollis Formation, largely as sills, in a number of places and is overlain unconformably by the Plum Tree Creek Volcanics. The Yeuralba Granite has contact metamorphosed the Tollis Formation and Maud Dolerite in this area (Kruse et al., 1994). It is possible that the Maud Dolerite is of similar age to the Zamu Dolerite (Ahmad and Hollis, 2013).
In the immediate Gold Creek deposit area, the Tollis Formation consists of lithic sandstone and siltstone to the west and mafic tuffs to the east. The latter probably belong to the Dorothy Volcanic Member (Morrison and Treacy 1998). At the Gold Creek Deposit, mineralisation is associated with intense quartz veining, largely concentrated within a discrete lode at the southern end of a north-trending fault. The latter separates the mafic tuffs to the east from the sedimentary rocks to the west. Fine-grained mafic to intermediate dykes are present in the mine succession, specifically in the immediate footwall of the deposit (Ahmad and Hollis, 2013).
The orebody comprises stockworks and massive quartz veining, silica flooding, brecciation and intense graphitic and chloritic alteration. Sulphides make up ~5% of the orebody, comprising pyrite and arsenopyrite with gersdorffite, occurring as disseminations, although there are also massive sulphide intervals containing up to 50% pyrite (Morrison and Treacy 1998). The orebody is 10 to 20 m thick, 150 to 200 m long, east dipping and steeply doubly plunging. In 2000, AngloGold Ltd mined about 180 000 t of oxide ore averaging 3.5 g/t Au and processed it at the Union Reefs mill (Ahmad and Hollis, 2013).
The current JORC-compliant Resource at Gold Creek is estimated at (Gilman et aI., 2009):
10.36 Mt @ 3.02 g/t Au.
Total past production has been 0.18 Mt @ 3.5 g/t Au.
(Source: Porter GeoConsultancy, www.portergeo.com.au, 2015)
