The graphite mineralisation at Siviour is hosted within a sequence of schist, micro-gneiss and metasedimentary rocks. The mineralised zone has a simple tabular geometry and the main portion of the deposit is oriented east-west.

The geometry of the Siviour Graphite Deposit is generally flat-lying, with thick, flat, gently folded graphite mineralisation sitting from within 5 m to 15 m of surface. This orientation facilitates a single shallow mining design that can be mined via conventional open pit mining methods.

The DFS pit optimisation and mining study resulted in a mining schedule conducted in 14 stages mined over a period of 26 years. Mining commences in the southern portion of the orebody to permit mining of a higher-grade corridor in the mine’s first year.

The proposed mining method is conventional truck and shovel open pit bench mining. Free digging in alluvial material makes up around 15% of all overburden, while drill and blast is required for all other lithologies.

Initially, mining will be conducted on a 24-hour basis in order to access high grade ore as soon as possible, before dropping to day-shift only in years 2 and 3. Mining will return to a 24-hour operation in Year 5, coinciding with the process plant expanding to 1,650ktpa capacity.

The DFS considers the construction of two 825ktpa processing plants, for a total processing capacity of 1,650ktpa, with the construction of the second plant to potentially be funded from projected cash-flows derived from graphite sales from the first plant. The plants are based on identical designs.

Crushing
Crushing will occur in two stages. In the first stage, a primary jaw crusher will crush ore from the pre-blended ROM pad, and crushed product will be conveyed to a scrubber. The scrubber oversize will be crushed in a secondary pebble crusher and conveyed back to the scrubber feed. The primary crushing circuit operates at higher capacity than the mill to allow for a crushed ore stockpile.

Grinding
Crushed, scrubbed ore will be conveyed to a primary rod mill to achieve flotation feed of P99 425 µm. The mill discharge will be collected in a hopper before being pumped to a vibrating screen, with oversized material recycled back to the rod mill. The fine ........