Sunrise Dam Gold Mine

Sunrise Dam Gold Mine

Sunrise Dam Gold Mine

Location: Laverton, Western Australia.

Product: Gold.

Geological Settings: The deposit is hosted by the Archaean Norseman-Wiluna belt, in the Eastern Goldfields Province of the Yilgarn Craton. The deposit falls within the structurally complex Laverton Domain, which is characterized by tight folding and thrusting. A number of other Au deposits lie within or near the margins of the Laverton Domain, including Laverton, Granny Smith (this volume), Red October (this volume), Childe Harold, Lancefield and Keringal. Most of these deposits are hosted by metasedimentary rocks, a distinctive feature of the Laverton region relative to other parts of the Yilgarn Craton.

Host Rocks: The host rocks are shallow-dipping interbedded Archaean metasedimentary, metavolcaniclastic and felsic to intermediate metavolcanic rocks (Newton et al., 1998). The metavolcaniclastic rocks are interbedded with BIF. In general, they are thick, bedded to massive and fine upwards. The BIF units are typically 2-10 m thick and commonly grade into magnetite-rich tuffs. A 20-40 m thick mafic intrusive postdates the metavolcaniclastic sequence on the western side of Cleo. Quartzfeldspar porphyries also intrude the sequence at both Cleo and Sunrise and, at Cleo, post-date the mafic intrusive.

Mineralization: The Sunrise Shear, within the Archaean rocks, controls geometry of the mineralization and is thought to have been the main conduit for Au-bearing hydrothermal fluids (Newton et al., 1998). Pyrite replacement of BIF accounts for most of the primary mineralization and is well developed where the shear zones, parallel to bedding, follow the contact of BIF with less competent units. Gold is also associated with quartzankerite- pyrite veins and pervasive ankerite-silica-sericite-pyrite alteration of intermediate volcaniclastic host rocks. Thin quartz-carbonate veins also host Au, but are mostly located in the Sunrise part of the deposit. Supergene mineralization has developed in the weathered bedrock and in transported cover in the eastern part of the study area.

Regional geology and setting of the Sunrise-Cleo Au deposit

(after Newton et al., 1998)