Open-pit mine and heap leach operations
Kyzyl kum desert, Uzbekistan
Two million oz
Navoi Mining & Metallurgy Combinat
The Muruntau gold mine located in Uzbekistan is one of the largest open-pit gold mines in the world. It is also the world’s fifth deepest open-pit mine. It produces 66t gold per annum. The state-owned company, Navoi Mining & Metallurgical Combinat (NGMK) owns and operates the mine.
The mine was discovered in 1958. It measures about 3.5km by 3km and has a current mining depth of 600m, which is planned to be extended beyond 1,000m. Surface mining works commenced in 1967.
The Muruntau gold mine produced more than two million ounces (Moz) of gold in 2020.
Geology, mineralisation and resources of Muruntau gold mine
The gold mine is located in the Kyzyl Kum Desert of Uzbekistan. The Kyzyl Kum area is made up of three main tectonic units, of which the oldest and major unit is the Besopan formation. The rocks are classified to be of Lower Palaeozoic carbonaceous and sulphidic clastic segments.
The Muruntau deposit is located within the Beltau-Kurama volcano-plutonic belt. The belt stretches in arc shape for 1,300km to 1,350km from the Valeryanov zone of the Urals in the west to the Chatkal ridges in the east.
The region has huge deposits of turquoise along with gold and arsenic deposits. Gold occurs in micro assemblages together with tellurides and selenotellurides of Bismuth mineral. The Tashkura region within the mine produces high-quality phosphorite.
The gold mine is estimated to hold more than 150Moz (4,000t) of resources.
Mining at Uzbekistan’s Muruntau gold mine
The Muruntau gold mine employs open-pit mining and heap leach processing. Gold mining is conducted using a truck and conveyor ore transportation system. The overburden is taken to the crushing and transhipping points using cyclic flow technology.
The ore is transported using a steeply inclined SIC-270 conveyor, one rumble, two spreaders and two conveyer lines with a belt width of 2,000mm.
The conveyor has a lifting height of 270m and an angle of 37°, which reduces the length of the ore mass transport by road by more than 3.5km.
The conveyor can handle one million tonnes of ore per year with a hill-climbing ability of approximately 37%. It has a capacity of transporting 50,000t per day.
The rock is dumped directly to the surface using Rocky loader-stacker-3500 dump hopper. The grinding loading complex comprises of grinding-loading point and loading-storing complex.
The ore is crushed using Metso LT160 crusher equipped with an advanced Metso DNA automation system. It includes a four-stage ore crushing system and a screening system. Crushed ore is transported to the hydrometallurgical plant for refining and gold production.
Ore processing and gold extraction at Muruntau
Processing of ore at the Muruntau mine is performed at hydrometallurgical plant No. 2 (HMP-2), which was installed in 1969.
The crushing and sorting complex processes the off-balance ores from the open-pit stockpiles to increase the ore feed reliability.
Gold is extracted using the heap leaching method that helps in the efficient extraction of gold, even from low-grade ores. Sorption and filter-free process is used for extracting the gold. It also extracts refined sliver and palladium by-products.
Details of construction and machinery used at the gold mine
The mining fleet of Muruntau includes 200 BELAZ-75307 mining dump trucks of 220MT capacity. In addition, two Hitachi excavators with 19.4m³ bucket capacity and one Russian-made ECG-15M excavator with 15m³ capacity are used.
Stage V Muruntau development
Stage V Muruntau development project is the biggest of the 27 projects to be executed by Navoi between 2017 and 2026. The project is the part of the Uzbekistan Government’s $3.63bn investment plan to modernise the country’s mining industry and increase the gold output.
The stage V development is estimated to cost $733.9m for underground ore extraction and modernisation of the existing mining fleet, of which Navoi will invest $445.9m for the expansion while $228m will be funded by a loan from the Uzbekistan Fund for Reconstruction and Development.
The project will uncover the reserves at the northern side of the open pit and will explore the reserves of the Besapantau, Chukurkuduk, Balpantau and Tamdybulak deposits. It will increase the volume of production and ore supply to HMP-2 to 50Mt/y.
The project will employ Austria’s Doppelmayer’ RopeCon® suspended conveyor system to transfer ore from the open pit to the surface. RopeCon provides a handling capacity of up to 25,000t/h.
Contractors involved with Uzbekistan’s Muruntau gold mine
Alteko was awarded the contract for installing the ore mining-and-transport complex at Muruntau mine. Novokramatorsk Machinery Plant provided the spare parts and components for the conveyor complex.
Zarafshan Construction Administration (ZCA) was contracted to perform civil construction works for the mine. Metso was awarded the contract to provide Nordberg LT160 crusher for the mine. It also provided two MP1000 cone crushers, screens and VSI impact crushers as part of the contract.
BELAZ was awarded the contract to supply 220MT mining dump trucks and BELAZ-76135 water-sprinkler.