Carosue Dam Operations (CDO) includes the Carosue Dam Project, the Porphyry Project, and the Deep South Project. Northern Star acquired the original CDO assets in 2006 and commenced commercial gold production in 2010.
CDO’s tenement holdings and gold deposits are located in one of the world’s most prospective gold provinces, incorporating the Laverton and Keith Kilkenny Tectonic Zones, northeast of Kalgoorlie, Western Australia.
GEOLOGY & MINERALISATION
The flagship Karari-Dervish deposit sits along the regional NNW-trending Keith-Kilkenny fault zone within the eastern edge of the Norseman-Wiluna greenstone belt. The Dervish deposit is off set approximately 500m to the North of Karari by the Osman fault.
The deposits are lithologically and structurally controlled, offset along a series of major faults running NE-SW and NW-SE, as well as intruded by large lamprophyre units post-mineralisation.
The lithology comprises primarily intermediate felsic volcaniclastic sandstones, intermediate tuffs and intermediate porphyry units intruded by granites of varying composition, with stratigraphy dipping generally to the east at approx. 60 degrees.
Mineralisation is dominated by pyrite and hosted in broad hematite altered sandstone units with a central high grade siliceous core light-moderately dipping to the North.
MINING
Karari-Dervish Underground
The mining method is longhole open stoping with paste fill. The open stopes are backfilled with paste utilising tailings from the Carosue Dam Mill.
The orebody is accessed via two declines, with 25m levels accessed via an end on access with strike ore drives and then stoped out via longitudinal retreat stoping.
Porphyry Open Pit Mining Centre
At the Porphyry Open Pit Mining Centre, there are currently two open pits being mined in unison - Million Dollar and Maingays. Ore from both pits is hauled to the mill at Carosue Dam. Porphry has future underground potential.
PROCESSING
The Carosue Dam processing circuit is a conventional CIL plant with a hard rock processing capacity of 4.0M tonnes per year. The process consists of secondary crushing with a single toggle jaw crusher followed by a cone crusher, in closed circuit with a double deck screen. The crushing circuit presents feed to a low aspect primary mill followed by a secondary regrind mill. The grinding circuit incorporates a gravity circuit followed by a CIP process.