2012 $1 Silver Proof Coin, Wheat Sheaf Dollar. Australia's place in the global economy has been built on the foundations of primary industry. No longer simply 'riding on the sheep's back', Australia supplies goods such as iron ore, wheat, sugar and beef to over 200 countries. Certificate of Authenticity is included with this coin numbered 2609. Mintage 12,500. Please contact Adelaide Exchange Jewellers to find out more on this item.