The Bacterial Oxidation (BACOX) Plant at Laizhou Shandong Province China ù The First Three Years of Operation

By the year 2000, China was the sixth largest gold producer in the world, with about one-quarter of total production being derived from refractory or semi-refractory deposits. Although bacterial oxidation plants had been previously tried in China using local technology, these plants had not been commercially successful. The Laizhou Gold Enterprise (Tarzan BioGold Co Ltd) located in Shandong Province, undertook to modernise their gold processing facility in 2000 with the introduction of Bacterial Oxidation (BACOX) Technology. In 1997 BacTech Australia and Mintek of South Africa had formed a technology partnership, combining forces in the provision of bioleach technology. Under a cooperation agreement, BacTech/Mintek were chosen as the preferred technology providers for this first application of commercially proven bacterial oxidation technology within China. The paper describes the successful operation of this plant over the last three years. The events of project implementation are described, from the metallurgical testing of concentrate; through to the commissioning at the design throughput of 100 tonnes per day resulting in 80 000 ounces (2.5 tonnes) per year of refined gold. Process aspects of the operation encountered over the last three years are discussed which illustrate the robustness of the operation. The success of the bioleach facility has led to an advancement of plans to double plant capacity and some of the innovations, which may be employed in this expansion phase, are discussed.