Polyus is the largest gold producer in Russia and one of the top ten gold miners globally with the lowest cost position. Based on its 2018 Ore reserves and Mineral Resources, the Polyus group ranks third by attributable gold reserves among the world’s largest gold mining companies. Olimpiada Gold Mine is Polyus’ largest operation located in the Krasnoyarsk Krai region of Russia. The mine began production in 1996 and currently accounts for over half of the company’s total gold output. The ore mined at the site is processed at three plants with a combined capacity of 13 million tonnes of ore annually
Long relationship with Outotec
Polyus has a long relationship with Outotec. To date Outotec has modernized seven existing thickeners and supplied a 30-meter thickener and automation equipment to their concentrator plants. Outotec has also supplied leading-edge automation and analysis technologies for Polyus to help optimize their flotation circuit further, including PSI 300i online analyzer, FrothSense froth imaging analysis camera, LevelSense slurry/froth interface tool and an ACT advanced control system.
SkimAir flash flotation project at Olimpiada
The SkimAir flash flotation project commenced at Olimpiada in Autumn 2014 with pilot and laboratory-scale test work. The first trial was conducted at the Olimpiada ZIF-3 concentrator (ZIF is a Russian acronym for gold recovery concentrator). This concentrator has 3mm gravity circuit pre-screen underflow. In the trial a side cut from this gravity circuit pre-screen underflow was directed to a SkimAir 3 test unit.
During the pilot test program the following conditions were investigated:
- Reagent dosing
- Feed % solids
- SkimAir operating parameters
The pilot test program proved that the Olimpiada gold floats very fast. The measured gold stage recovery for the test unit varied from 50 to 75 % and concentrate gold grade from 68 to 187g/t. The average gold recovery and grade were 62.4% and 111.5g/t, respectively. During the trial the estimated feed rate of the unit varied from 3.8 to 5.8 t/h and feed solids content from 54.6 to 69.7% solids.
The results proved that the Olimpiada type ore was suitable for the flash flotation technology. The customer decided to proceed with the front-end-engineering of a full-scale SkimAir installation. Following the completion of this front-end-engineering and based on the promising pilot test results, Polyus ordered one SkimAir 500 flash flotation cell in 2016. The cell was installed in the Olimpiada ZIF-4 concentrator on one of the parallel processing lines, enabling a comparison of lines with and without SkimAir.