The regional and local geology of the Project area is well understood having a long exploration and development history. Stratigraphically the oldest rocks are the Cambrian aged sequence containing locally the Tyndall Group, Central Volcanic Complex, Yolande River Sequence and andesitic volcanics and intrusives. These are overlain by the late Cambrian-Ordovician aged Owen group and Silurian aged Eldon Group. Quaternary/Tertiary deposits, including glacials, complete the regional geological sequence.

Prince Lyell -Deeps/North Flank/D Panel/Royal Tharsis
The footwall of the mineralisation at the Prince Lyell Deeps is defined by the Great Lyell Fault, which juxtaposes the Cambrian volcanic host rocks against a later Cambro-Ordivician sedimentary sequence. The Great Lyell Fault truncates the mineralisation at depth.

The mineralisation consists of disseminated to veinlet pyrite-chalcopyrite hosted within strongly altered and schistose volcanic rocks. Alteration consists of a chlorite-pyrite+/-magnetite core surrounded by a muscovite pyrite envelope. The North Flank/D Panel and Royal Tharsis mineralisation and alteration is similar to the Prince Lyell, however the former has a stronger stratigraphic control.

Dimensions:
Prince Lyell North Flank: the resource has dimensions of 490 m in height, 1,500 to 2,090 mRL (2,000 mRL represents sea level and the surface is approximately 420 m above sea level). The strike length of the resource is up ........

The initial mine development is proposed to access the upper levels of the Prince Lyell D Panel and will provide for access drives across to the Western Tharsis deposit from the existing Prince Lyell decline. Production is planned to commence within the first year of mining recommencing.

The mine design parameters for the Mt Lyell project are generally based on the parameters previously used to mine the Prince Lyell deposit, being SLC. The Copper Chert mine design parameters have been based on industry best practice, as this is currently planned to be a Longhole Open Stoping method of mining. Equipment selection and planned operational production rates have been considered during the process.

The proposed mining method for Prince Lyell and the majority of Western Tharsis is SLC. The mining method for upper Western Tharsis will be reviewed in the FS to see if a form of open stoping is both more suitable and provides improved project economics.

SLC is an underground bulk mining method commonly applied to large low-grade homogeneous deposits with large vertical extents. SLC is a mass mining method based upon the utilisation of gravity flow of blasted ore and caved waste rock. The method functions on the principle that ore is fragmented by blasting, while the overlying host rock fractures and caves under the action of mine-induced stresses and gravity. The caved waste from the overlying rock mass fills the void created by ore extraction.

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