Ridgeway

Porphyry copper (Cu-Au) deposit in New South Wales, Australia

Names and other identifiers

GMRAP ID 4068
Tract name Macquarie (009pCu8002)
Group name Cadia Group
Included sites Group includes Big Cadia, Cadia East open pit, Cadia East underground, Cadia Far East, Cadia Hill open pit, Cadia Quarry, and Ridgeway deposits and Little Cadia prospect.
Site status deposit

Geographic location

Country Australia
State or province New South Wales
Geographic location 148.9759, -33.4353
Geologic map unit 148.9759, -33.4353
Nearby data

Geologic information

Deposit type Porphyry copper
Deposit subtype Cu-Au
Age (Ma) 456Ma
Age determination method U-Pb zircon, titanite
Age range 456.9 ±7.2 Ma (titanite), 455.8 ±4.4 Ma (zircon)
Age reference Wilson, Cooke, Stein, and others (2007, p. 15)
Minerals albite, actinolite, bornite, chalcopyrite, chlorite, epidote, gold, K-feldspar, magnetite, molybdenite, pyrite
Associated rocks volcanic rocks, shoshonitic volcanic and volcaniclastic rocks, shoshonitic diorite, monzonite, monzodiorite, and quartz monzonite porphyries
Tectonic setting island arc
Stratigraphic age Middle Ordovician–Late Ordovician

Commodity and development information

Development status Producer
Major commodities Au, Cu
Minor commodities Ag
Tonnage (Mt) 154Mt
Cu grade (%) 0.385%
Au grade (g/t) 0.73g/t
Ag grade (g/t) 0.81g/t
Contained copper 593,000t
Gold-Moly ratio -9999

Reference information

Comments Location, tonnage and grade of measured + indicated + inferred resources from Geoscience Australia (2010). Sheeted quartz veins, stockwork quartz, veins, disseminations, and skarn; top is 500 m below surface, beneath Miocene basalt and paleosurface weathered to 50 m.
Study area name Australia
References Holliday and others (2002); Fredricksen (2006); Cooke and others (2007); Wilson and others (2003); Wilson, Cooke, Stein, and others (2007); Geoscience Australia (2010)
Site reference Bookstrom and others (2014)
Cooke, D.R., Wilson, A.J., House, M.J., Wolfe, R.C., Walshe, J.L., Lickfold, Vanessa., and Crawford, A.J., 2007, Alkalic porphyry Au-Cu and associated mineral deposits of the Ordovician to Early Silurian Macquarie arc, New South Wales: Australian Journal of Earth Sciences, v. 54, p. 445–463. (Also available at http://dx.doi.org/10.1080/08120090601146771.)Fredricksen, Dean, 2006, Sustainable gold and copper production, Cadia Valley operations, in Mines and Wines Symposium—Mineral Exploration in New South Wales, Cessnock, Australia, May 25–26, 2006, Proceedings: Sydney Mineral Exploration Discussion Group, 36 slides, accessed September 3, 2013, at http://www.smedg.org.au/M&WProg.htm. (Also available at http://www.smedg.org.au/Fred.ppt.)Geoscience Australia, 2010, Australian mines atlas: Geoscience Australia Web page accessed October 20–December 27, 2010, at http://www.australianminesatlas.gov.au/.Holliday, J.R., Wilson, A.J., Blevin, P.L., Tedder, I.J., Dunham, P.D., and Pfitzner, Michael, 2002, Porphyry gold-copper mineralization in the Cadia district, eastern Lachlan fold felt, New South Wales, and its relationship to shoshonitic magmatism: Mineralium Deposita, v. 37, p. 100–116. (Also available at http://dx.doi.org/10.1007/s00126-001-0233-8.)Wilson, A.J., Cooke, D.R., and Harper, B.L., 2003, The Ridgeway gold-copper deposit—A high-grade alkalic porphyry deposit in the Lachlan fold belt, New South Wales, Australia: Economic Geology, v. 98, p. 1637–1666. (Also available at http://dx.doi.org/10.2113/gsecongeo.98.8.1637.)Wilson, A.J., Cooke, D.R., Stein, H.J., Fanning, M.C., Holliday, J.R., and Tedder, I.J., 2007, U-Pb and Re-Os geochronologic evidence for two alkalic porphyry ore-forming events in the Cadia district, New South Wales, Australia: Economic Geology, v.102, p. 3–26. (Also available at http://dx.doi.org/10.2113/gsecongeo.102.1.3.)