30 Dollars - Elizabeth II 4th Portrait - Koala - Silver Bullion Coin

The 1-kilogram silver Koala series, produced by the Perth Mint, carries an annually changing reverse design — a deliberate strategy adopted to encourage year-on-year collector demand rather than bulk accumulation of a static type. The 2011 issue falls within the series' mature period, after the format had already proven commercially successful through the 2000s.

Perth's capacity to strike coins at this scale reflects infrastructure built partly around its origins as the dominant refinery for Western Australian gold and silver output. The 100.6 mm planchet requires individual hand-feeding into the press.