The BHCP is located in a deformed and metamorphosed Proterozoic supracrustal succession named the Willyama Supergroup, which is exposed as several inliers in western New South Wales, including the Broken Hill Block (Willis, et al., 1982).

The project area covers portions of the Broken Hill and Thackaringa group successions which host the majority of mineralisation in the region, including the Broken Hill base metal deposit. The Sundown Group suite is also present. The extensive sequence of quartz-albite-plagioclase rock that hosts the cobaltiferous pyrite mineralisation is interpreted as belonging to the Himalaya Formation, which is stratigraphically at the top of the Thackaringa Group.

Exploration by COB has been focused on the discovery and definition of cobaltiferous pyrite deposits.

Mineralisation Style
The BHCP mineral deposits (Pyrite Hill, Big Hill and Railway) are characterised by large tonnage cobaltiferous pyrite mineralization hosted within siliceous albitic gneisses and schists of the Himalaya Formation.

Cobalt mineralisation exists within extensive pyritic horizons where cobalt is present within the pyrite lattice. Mineralogical studies have indicated the majority of cobalt (~85%) is found in solid solution with primary pyrite (Henley 1998).

A strong correlation between pyrite content and cobalt grade is observed.

The Thackaringa mineralisation comprises stratabound units of moderate to steepl ........

The BHCP considers a multi-open pit mining scenario that will extract ore using conventional drill and blast, load and haul and dump processes. The operation is planned to use excavator and rigid body trucks along with a fleet of auxiliary equipment. This proposed mining method is considered appropriate for the deposit style.

Up to 6.3Mt of ore will be hauled annually to a stockpile area (ROM) proximal to the processing plant located centrally to the pits and waste material hauled to the waste emplacements located in close proximity of each pit. During periods where the quantity of ore mined exceeds the quantity processed, additional temporary long-term stockpile areas may be utilised.

Mining loss and dilution was modelled by re-blocking the resource block models to a mining unit size consistent with practical mining constraints at the required production rate. The resource block models were estimated at a parent block size of 5m (east), 10m in (north) and 10m (elevation) then sub-blocked against interpreted domain boundaries to a minimum block size of 1.25m (east), 2.5m in (north) and 2.5m (elevation). The mining model re-blocked the sub-blocked resource model to a regular size of 2.5m (east), 5m in (north) and 5m (elevation). This has the effect of diluting blocks along the margins of the estimated mineralisation with dilution most apparent in thin zones such as the complex areas in the Railway deposit.

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