Improving overall gold recovery at Nordgold’s Suzdal mine, Kazakhstan

The Suzdal Gold mine is located 55 km southwest of the city of Semey (formerly Semipalatinsk) in the Znamenka Rural Administrative district within north-eastern Kazakhstan, and approximately 600 km east-southeast of the capital city of Astana. Suzdal operates an underground mine feeding a processing plant with crushing, grinding, flotation, BIOX, CCD and CIL circuits. 

Suzdal operates an underground mine feeding a processing plant with crushing, grinding, flotation, BIOX®, CCD and CIL circuits.  The Suzdal plant operates three proprietary Outotec technologies used in the treatment of refractory gold ore:

• The BIOX® process was developed for the pre-treatment of refractory gold concentrates.  The Suzdal BIOX® plant was commissioned in 2005 and was the first use of this process in Eurasia.
• The ASTER™ Process is a biological process for the destruction of cyanide and thiocyanate in leach residue solutions, allowing for the recycling or disposal of the detoxified solution. The Suzdal ASTER™ plant was commissioned in 2013 and allowed for an improved water management at the mine.
• The HiTeCC Process was developed for the recovery of preg-robbed gold from leach residues.  The Suzdal HiTeCC Plant was commissioned in 2016.

The Suzdal HiTeCC plant is the second application of this innovative Outotec technology.  Initial development of the technology was completed at Kirkland Lake Gold’s Fosterville Gold Mine in Australia, resulting in the successful installation of the HiTeCC process at the mine in 2009. 

Metallurgical test work was done by the Suzdal Technical team under the direction of the Outotec BIOX® Process Specialists and included laboratory tests and semi-commercial tests. The test work confirmed between 40% and 70% additional gold recovery can be achieved from both current and historical tailings.

The project was approved in 2015 and detailed design completed in December 2015.  Construction of the facility was started in July 2015 with commissioning of the plant completed June 2016.  The HiTeCC plant will allow Suzdal to process more than 130 000 tonnes of historical and current tailings per year at a potential recovery rate of between 40 % and 70 %. 

Nordgold invested US$5.8 million in construction of the state-of-the-art HiTeCC facility. The Company expects to fully pay back this investment in less than 20 months (assuming gold price of US$1,200/oz and 350 tenge/US$ exchange rate). The HiTeCC is expected to increase Suzdal production output by 9 -14 koz of gold doré per year for 10 years and the HiTeCC life-of-mine AISC is expected to be approximately US$420 per ounce.

About Suzdal mine

The Suzdal mine is located 55 km southwest of the city of Semey in Kazakhstan. Suzdal operates an underground mine, using the sublevel caving method with track drifts to produce gold doré.

Between 1999 and 2005, Suzdal has been using heap leaching to treat oxide ores. Since 2005, the mine has been treating sulphide ores using Outotec BIOX environmentally friendly technology. 

Today Suzdal operates one of the most technologically advanced gold processing plants in Kazakhstan, with crushing, grinding, flotation, BIOX, CCD and CIL circuits. Suzdal is the first mine in Eurasia to deploy the Outotec BIOX technology to treat sulphide ores. In 2013, Suzdal implemented Outotec Aster technology to treat and reuse process water.

Suzdal increased production in 2016 to 81.4 koz of refined gold from 75.3 koz in 2015.

*This case study has been written prior to the merger of Metso and Outotec.