SABC Circuit Operations at Eldorado?s Jinfeng Gold Mine

The Jinfeng gold mine is one of the three gold mines that Eldorado Gold has in China and it is the second largest gold mine in China. The mine is located in a relatively remote and mountainous area in the southwestern Guizhou province. The orebody is similar to the Carlin type deposit in Nevada. The mill throughput was designed to treat 3,600 tones per day. The ore comes from open pit mining and underground mining, and is fed to one-stage jaw crushing. The crushed ore is stockpiled, reclaimed and then fed to the SABC grinding circuit. After classification with hydrocylones, the ore is floated, and the resultant concentrate is oxidized biologically in a process known as BIOX®. The oxidized concentrate is then washed in a CCD circuit and finally leached with cyanide in a CIL circuit for gold extraction. Jinfeng produces about 180,000 oz of gold per year. This paper introduces operations and modifications of SABC circuit over the past three years, and then describes some technical characteristic of the SAG mill and other circuits in the processing plant. Major modifications and improvements on the SABC circuit are described in the paper, including: 1. Impacts of grinding ball and mill liner with respect to material selection, quality, hardness, manufacturing methods, and interactions between mill liner and grinding ball. 2. Effect of milling operation parameters on milling efficiency. 3. Impacts of SAG mill scats and modifications of grate size to improve mill throughput. 4. Design and construction of a pebble crushing system, and recycle the crushed scats to the SAG mill to improve mill throughput. With the above-mentioned modifications, 20% increase over the design in mill throughput has been realized over the past three years, and operating cost has been significantly reduced. However, some issues still remain, and thus process modifications and technical innovations are still needed.