The Gatsuurt gold property is located 90 km north of Ulaanbaatar in the Mandal Soum province of Selenge Aimag of central northern Mongolia.
The project is part of the larger Noyon mining and exploration license which is 100% owned by Centerra.
Alluvial gold in the region was first discovered in the1970s. It resulted in placer mining operations that continued until 2002. In 1996, quartz veins carrying visible gold were discovered in the bedrock floor of the placer. Centerra (then Cameco Gold Inc.) funded the 1997 to 2001 exploration programs and in 2001 acquired the project's owner/operator.
Gold mineralization is structurally controlled and occurs in clastic sedimentary and volcanic rocks immediately adjacent to a fault zone. By December, 2009, probable reserves were estimated at 1.3 million contained ounces of gold, measured and indicated resources were 500,000 ounces of contained gold, and inferred resources 200,000 ounces contained gold.
The Gatsuurt development is dependent upon the existence of the Boroo facilities and the operational support that the Boroo mining operations (100% owned by Centerra) can provide to the project which is 35 km southeast of the mine.
The project is to be developed by open pit mining methods and the ore processed by using a BIOX sulphide concentration circuit, CIP gold leaching and flotation techniques at the Boroo site.
Annual gold production would average 181,500 oz.
The Gatsuurt project is located in central northern Mongolia, a landlocked country that is bordered by Russia and China. It is the most sparsely populated country in the world and its inhabitants had predominantly embraced the Tibetan Buddhism.
Trans-Mongolian Railway, which links the Russian Ulan Ude Siberian station with the Chinese city of Jining by way of Mongolia, passes through Mandal territory.
The mining project is 30 km south east from Zuunkharaa city which boasts a population of 15,000 and a spirit and beverage factory that has the remarkable capacity of producing 15 tonnes of vodka in 24 hours.
The 1,000 km long Selenge River is the main river in Mongolia and passes through Selenge aimag before making its way to Lake Baikal (1,642 m in depth), a UNESCO heritage site.
The local climatic conditions at site can be quite severe, with temperature highs and lows of 39°C and -46°C, respectively, coupled with periodic high winds.
The project is located in the North Khentei gold belt of north central Mongolia which is bounded by the Bayangol and Yeroogol fault systems.
The gold belt has a long history of placer mining and includes several hardrock gold deposits. Placers and associated gold and arsenic in soil anomalies are aligned along the Bayangol and Yeroogol fault systems.
Other hardrock deposits located on trend with Gatsuurt include Centerra's Boroo mine and the Bumbat deposit.
Gatsuurt is located along the Sujigtei fault which is part of the regional Yeroogol fault system. The subvertical fault separates Permian rhyolites by the Boroo complex of granites and Kharaa series of metasedimentary rocks
The deposit is made of two distinct zones: the Central and the Main zones. The Central Zone lies on the southeast hangingwall side of the structure, whereas the Main Zone is on the northwest side, approximately 400 m to the southwest. The combined length of the two zones is approximately 1.5 km and their combined width is at least 300 m.
It is likely that the two zones once formed a single deposit and that post-mineral sinistral movement along the Sujigtei fault displaced the Main Zone from the Central Zone by some 750 m. Alteration consists of a quartz sericite-K-spar-pyrite-arsenopyrite assemblage.
At December 31 2007, probable reserves at Gatsuurt for the Central and Main Zones combined were estimated at 1 million ounces of contained gold, measured and indicated resources were estimated at 607,000 ounces of contained gold and inferred resources were estimated at 256,000 ounces of contained gold. By December, 2009, probable reserves had grown to 1.3 million contained ounces of gold, measured and indicated resources were 500,000 ounces of contained gold and inferred resources 200,000 ounces contained gold.
Mining & Operation
The Gatsuurt open pit operations are planned to operate as a satellite of Centerra's existing Boroo mining operation.
The mine development is planned to proceed in two phases, with the first phase
involving the mining and recovery of the oxide ore materials that exist in the near surface zones of the deposits. This oxide ore material is planned to be transported by overland truck haul to the existing Boroo mill for processing. Once oxide ore mining is complete, the second phase of the operation will commence involving the mining and recovery of the sulphide refractory ore material that makes up the bulk of the deposit. Ore will be rehandled by an excavator loading 30 t capacity tractor- trailer units that will transport the ore to the Boroo process plant. Haulage units will be 6 x 4 tractors and matching trailers produced in China. At full production of 4,800 tpd, a fleet of twenty-six (26) haulage units will be required. The ore haulage operation is planned to be contracted out.
The sulphide ore will be transported overland to the Boroo mill facilities once the process circuit modifications required for recovering gold from the sulphide ores is completed.
The Central Zone ultimate pit is approximately 1,000 m long, 300 m to 400 m wide, and 200 m deep. The pit is located in the floor of a narrow valley about 150 m in width.
The Main Zone Pit is located to the west of the Central Zone Pit, cutting across a side slope of the existing valley. The pit measures approximately 400 m in length and 200 m in width.
Mining operations would average35,000 tpd (ore + waste) or 4,800 tpd ore that would be stockpiled at mine site prior of being shipped to Boroo mill. Mining and ore haulage operations are planned to operate on a 350 days per year, two 12-hour shift basis.
Mining equipment include: one 172 m blasthole drill; one 12m3 to 15m3 hydraulic shovel; 90 t mechanical drive haul trucks; one 10.4m3 front-end loader; one 230 kW bulldozer; one 160 kW grader; water and fuel trucks.
A mine maintenance workshop is planned at the Gatsuurt site to provide support for the mining and ore haul equipment.
Oxide ore will be mined at a nominal rate of 2,000-2,500 tpd. The higher-grade oxide material from the Gatsuurt deposit is amenable to conventional gold cyanidation recovery methods using the existing Boroo mill facility.
Oxide ore would be crushed in a jaw crusher and wet-ground using a SAG mill followed by a ball mill in close circuit with hydrocyclones. Crushing facility is designed to process 1.75 Mt per year.
A Knelson concentrator is used to collect a gold concentrate and tails would be reporting back to the grinding circuit. Ground ore would be cyanide leached and gold in solution would be recovered in a carbon in pulp (CIP) circuit. Tailings are detoxified and heavy metals are removed before discharging them at a permanent tailings facility five km from the process plant.
Sulphide ore would be processed at a modified Boroo mill at a 4,800 tpd rate. Flotation circuit is designed to treat 217 t of ground ore per hour. Flotation concentrates would be thickened and subsequently subjected to bacterial oxidation in a two stage BIOX circuit. The resulting slurry to a counter-current wash circuit (CCD) and then neutralized. The neutralized slurry flows to the CIP circuit for gold leaching.
Annual gold production would average 181,500 oz.