DATE: Thursday 27th July 2000 - 5.30pm for 6pm
VENUE: 1st Floor, Rugby Club, Rugby (Crane) Place, Sydney
SPEAKER: Ken Maiden - Pegmont Mines
TOPIC: "Exploring for Copper in the Western Mount Isa Block"
While Mount Isa is by far the largest copper deposit in the western Mount Isa Block, ongoing
exploration is demonstrating that the region has excellent potential for discovery of other copper
deposits.
The deposits are significantly different from the "classical" stratabound copper deposits of the
European Kupferschiefer and the Central African Copperbelt. They resulted from a regional
hydrothermal event focussed along faults during waning metamorphism. Metal concentrations were
precipitated in dilational sites such as fault splays, intersections and "jogs". Deposits may be either
broadly stratabound or transgressive to stratigraphy and are associated with intense alteration and
brecciation of the host rocks. The style of mineralisation varies from veins and stockworks to
breccia fillings, disseminated zones and massive replacements. In detail, there is considerable
variation in deposit geometry and mineralisation style resulting from different host rocks, different
fault geometry, and different fluid movement history. From a commercial perspective, important
features are (a) they have high copper grades, (b) they may have associated metals such as cobalt and
gold, and (c) deep zones of leachable supergene ore are developed.
Mineralised systems may be expressed by:
· Zones of fracturing, brecciation and quartz-carbonate-sulphide veining
· Alteration: silica-dolomite with pyrite, chlorite, Fe carbonate, hematite, muscovite
· Siliceous gossan, gossanous breccia, quartz-carbonate-limonite veins, massive hematite
· Geochemical anomalies
· Electrical geophysical anomalies
· Subtle gravity anomalies due to silica-dolomite alteration.
BRIEF C.V. - KEN MAIDEN
1968: BSc (Hons), UNSW
1972: PhD, UNSW: Project: Deformation and metamorphism of the Broken Hill deposit
1972-77: Geologist, CSR Limited: Stuart Shelf (Mount Gunson) and Bangka Island, Indonesia
1977-79: Lecturer in Economic Geology, Canberra CAE
1979-86: Senior Lecturer in Economic Geology, University of the Witwatersrand, Johannesburg.
Research on stratabound and VHMS copper deposits in Namibia and Zimbabwe
1987-89: Geological consultant, based in Sydney
1990-95: Principal Geologist, MIM Exploration: Mainly in the Mount Isa Block
1995-2000: Principal, Kraton Geoscience (geological consultant)
1996-2000: Director, Kalahari Mining NL: Copper projects in Namibia and Botswana
SMEDG Poet-in-Residence for post-Conference wrap-ups.
2001 Symposium Limericks