Going for Gold

Posted on Nov 1, 2011 in GPM in the media

Mining Magazine
by Carly Lovejoy
1 November, 2011

Georgia’s mining industry is experiencing a boom. Carly Lovejoy looks at what the future holds for GeoProMining’s Madneuli copper-gold mine.

Madneuli is an integrated copper-gold mining and processing complex in the Bolnisi region of southern Georgia, located approximately 80km from Tbilisi in the area bordering Azerbaijan and Armenia. It comprises the Madneuli open-pit mine and processing facility, which produces gold-bearing copper concentrate through flotation processing.
The operation is located in a mountainous region that is crossed by the Mashavera and Khrami rivers, with elevations ranging between 500m and 1,300m. Temperatures in the region range from 4-25○C, with average snow fall levels of between 30cm and 60cm per year.
Madneuli can be accessed year-round by road, and it is located 450km and 550km, respectively, from the Black Sea ports of Poti and Batumi. It also has direct access to railway lines that connect it to other countries in the Caucasus and CIS regions.
GPM (GeoProMining) currently owns 99.16% of Madneuli (with the remaining shares held by former and current Madneuli employees). GPM is a privately-owned diversified mining company with operating assets in Armenia, Georgia and Russia. The company acquired Madneuli in 2005 as part of the Georgian privatisation programme.

History

Georgia’s mining industry received a boost in the mid 20th century when, due to a sharp increase in the global demand for metals, its mineral wealth became the subject of large-scale geological exploration and development. However, the mineral resources of the Bolnisi region have been exploited for many hundreds of years. The area has been identified as a centre of non-ferrous metal ore extraction, and development of alluvial gold deposits, evidenced by the presence of ancient roadways and furnaces has been dated around 4th-3rd century BC.
The Madneuli formation is part of the Artvin-Bolnisi mineralisation zone, a large gold-base metal deposit that spans the Bolnisi mining district and extends from southern Georgia and northern Armenia into northern Turkey, Bulgaria and Romania. Other formations of interest include: Tsiteli, Spolei and Sakdrisi. The region is part of the Alpine-Tethian Belt and its main geology and mineralisation is thought to be a product of the subduction of the Afro-Arabian plate beneath the Euro-Asian plate, which resulted in the closure of the Tethys Ocean and the subsequent uplift of the region.
Mineralisation within the tectonic corridor is widespread, and mainly comprises Kuroko-style Cu-Pl-Zn-Ag-Ba-Au deposits, porphyry Cu-Au deposits and stockwork vein Au deposits.
The Madneuli mine has ore of variable grades. Exploration work began at Madneuli in the mid-1940s, and results from a drilling programme conducted by the USSR in the 1950s formed the basis for the development of a mine.
Construction at Madneuli commenced in 1968 and the mine became operational in 1975, extracting copper, barite and gold-silver bearing ore. The open-pit mine ramped up to full capacity in 1978 and has operated continuously since. The plant originally processed gold-barite ores, but expanded in 1986 to include processing of gold-copper ores.
A new phase of development began in 2006 following GPM’s acquisition of the Madneuli and Quartzite properties and a new laboratory was inaugurated in 2009. The production process became automated, allowing significant increases in plant throughput.
The company also conducted a reassessment of the mines reserves which revealed the presence of economically-viable gold reserves hosted in secondary quartzite.
In 2008 and 2009, the group mined and processed higher grade ore from the mine. In 2009, as a result of high gold prices, management made the decision to mine and process lower-grade ores in order to extend the life of the mine.

The mine

The Madneuli complex includes an open-pit mine, crushing facility and a processing plant that uses flotation to recover the ore. The plant has a designed throughput capacity of 2.5Mt/y of copper sulphide. The site also has mechanical workshops, a laboratory, fuel storage facilities, offices, warehouses and a rail load-out facility.
The Madneuli mine covers an area of 1.3km2 and the main pit has a total depth of 350m. The mine features stepped walls with batter angles between 45 and 70 degrees, berm widths of 5m, total slope angles between 35 and 50 degrees and 20m benches.
Mining is carried out using drilling and blasting techniques. The company operates a fleet of Tamrock (now Sandvik) and Ingersoll Rand, crawler-mounted blasthole drill rigs. Rock is loaded by excavators, and both ore and overburden is transported for milling and processing by a fleet of 42t BELAZ haul trucks.
Prior to concentration, run of the mine ore is delivered to the crushing facility where it is broken into particles 0-25mm in diameter in three crushing stages, before being reduced to fine particles less than 74 microns in eight ball mills.
Crushed ore is delivered to the processing plant by a belt conveyor where it is subjected to flotation. The obtained copper concentrate is then delivered for concentration and filtration, and the flotation tailings are pumped via a 3km-long pipeline to the tailings dump for storage.
Madneuli has a long-term contract in place with Georgian Railways for the transportation of copper concentrate. Once the copper concentrate has been dried to a humidity of 8-10%, it is packed into 2t bags and loaded into railway cars for transport to the Black Sea port of Poti.
Madneuli produced 9,800t and 6,700t of copper in 2009 and 2010 respectively. Gold production remained stable through 2009 and 2010 at approximately 26,000oz.

Going forwards

GPM is currently working on plans to expand and modernise the Madneuli processing plant which would allow an increase in the mines overall productivity. The company has also undertaken extensive exploration work, both at the existing Madneuli mine and within neighbouring areas covered by current licenses in order to increase Madneuli’s reserves and extend the life of the mine. One of the development projects that is focussed on the Sakdrisi deposit is located about 2km from the existing Madneuli mine, and copper-bearing ore from the project will eventually be processed at the Madneuli facility.
Another of GPM’s mining operations, Quartzite, is a gold-silver mining and processing complex located directly adjacent to the Madneuli mine’s southwest edge. Quartzite commenced operations in 1997, and heap leaching of pre-existing gold and silver oxide stockpiles from Madneuli began at Quartzite in 1998. In addition to processing existing ore stockpiles and ore that Quartzite purchases from Madneuli, Quartzite started processing ore mined at the Sakdrisi project in 2010.
GPM plans to increase the annual output at Madneuli by implementing a treatment programme for mine tailings. Significant investments are also planned for the expansion of the mine tailings dam, mining fleet replacements, reverse circulation drilling and maintenance.