pebble conglomerate. The conglomerate sits within the centre of the deposit and forms a central tor flanked by an apron of sulphides, which forms an elongate ribbon plunging west-southwest. The Mons Cupri rhyolite is in the footwall and shows typical silica-chlorite alteration. The Cistern Formation conglomerates are intensely silicified. Whim Creek is hosted within the Rushall Slate, which is a finer-grained equivalent to the Cistern Formation. The Whim Creek deposit forms a ribbon-like sulphide shoot which plunges to the south or south-east. Regionally, several sub-economic deposits and prospects are known, including the Salt Creek VMS deposit, the West Balla VMS prospect and the Balla Balla VMS prospect. Ore processing The current mining operation at Whim Creek consists of an open cut mining operation, utilising drill-and-blast, trucking ore from Whim Creek and Mons Cupri to a central heap leach hydrometallurgy operation midway between the two. The operation runs via contract mining, with a fleet of five haul trucks and two production drill rigs. Ore is crushed and screened to <20 mm, agglomerated with concentrated sulphuric acid, and stacked on heaps around 6 m high, which are placed atop a plastic membrane. The ore is irrigated via drippers with a dilute sulphuric acid solution and the leach liquor collected, and directed into a solvent extraction plant where the dilute lixivaint is purified. The concentrated raffinate is then pumped into an electrowinning plant where 99% or greater purity copper cathode is produced for direct sale. The mine's nameplate capacity is 15,000 tonnes per annum of A-grade copper cathode. Production averaged around 12,000 tonnes per annum for 2006-07. Barren overburden is stockpiled in proximity to the open pits. There is an option to continue the operation as a sulphide crush-grind and flotation operation, as the current oxide ore bodies continue at depth as primary sulphides. Balla Balla River pollution In 2019, the owners of the mine were handed an Environmental Protection Notice by the Department of Water and Environmental Regulation because of seepage of heavy metals from the mine into the Balla Balla River, considered a serious pollution risk. While in care and maintenance and with no active mining, Black Rock Minerals re-processed existing stockpiles through a small process plant and heap leach. Copper levels of 3.5 milligrams per litre were recorded in the local drinking water, well above the permitted level of 0.002 milligrams per litre. The small scale re-processing at Whim Creek