Australian firms St Barbara and Catalpa Resources are planning to merge to form a mid-tier gold company.

The A$865m ($914m) merged company will have four Australian production assets, with production capacity of about 480,000oz of gold in 2012.

Both the firms will enter into a merger implementation agreement on terms and conditions customary for the transaction, including obtaining of all necessary shareholder, regulatory and court approvals.

St Barbara said its expertise in underground mining at Leonora and Southern Cross in Western Australia is a natural complement to Catalpa’s future underground expansion options at its Edna May project, which is 75km from St Barbara’s 120,000oz per annum Southern Cross operation.