The Skouries copper-gold porphyry deposit in the Chalkidiki region is being developed amid huge protests in Greece.
Eldorado Gold started the Skouries mine construction in 2013 and expects to begin production in 2016. Image courtesy of Schizophonix.
The deposit is a combined open pit and underground mining operation. Image courtesy of Eldorado Gold Limited.

Eldorado Gold (EGL), through its Greek subsidiary Hellas Gold, is developing the Skouries copper-gold porphyry deposit located in the Chalkidiki Peninsula of Greece.

The mine is proposed to be developed in two phases, with the initial phase comprising of a small, open pit and the second phase an underground operation. It will produce copper-gold concentrate by using the flotation process and gold doré by using a gravity circuit.

Construction of the copper-gold project began in 2013 and is expected to commence production in 2016. The project is anticipated to have a mine life of 27 years.

The gold mining project is protested heavily over environmental concerns by the local community of Chalkidiki.

Skouries copper-gold deposit location and geology

The Skouries copper-gold deposit is located within the Kassandra Mines Complex, which is a part of the Chalkidiki Peninsula in northern Greece. Located approximately 100km east of Thessaloniki city, the complex covers 317km² and consists of a group of mining and exploration concessions.

The deposit is hosted predominantly in a near-vertical pipe-shaped porphyry stock that has a surface expression of approximately 200m in diameter. It is centred on a porphyry stock that intruded schist and gneiss of the Paleozoic Vertiskos Formation belonging to the Serbo-Macedonian Massif.

The porphyry is defined by more than four intrusive phases of probable monzonite to syenite composition, containing potassic alteration and related stockwork veining.

Skouries mine reserves

As of 31 December 2014, the Skouries mine is estimated to contain 150 million tonnes (Mt) of ore grading 0.76g/t of Au and 0.51% Cu. It is estimated to contain 3.7 million ounces (Moz) of gold and 767,000t of copper.

Mining and processing of ore at Skouries

Conventional open-pit mining method will be applied at Skouries for a period of six years, followed by underground mining from the seventh year. The open-pit mining will include drilling, blasting, loading and hauling of ore and waste materials for processing and waste disposal.

“The resulting copper-gold concentrate will be thickened and filter-pressed before transporting to the port of Stratoni.”

Sublevel open stoping (SLOS) is proposed for the underground mine, which will be accessed by a service decline (ramp) and a production shaft. Each production level will be spaced at 25m intervals.

The processing plant is designed to have a nominal throughput of approximately 881 tonnes per hour (tph). Ore from the open pit will be crushed in a crushing station and discharged onto a covered conical stockpile, which will also receive the crushed material from the underground mine at a later stage.

The material will be reclaimed from the stockpile using three variable speed apron feeders and conveyed to the primary grinding circuit. The two-stage wet grinding circuit will comprise a SAG Mill and a ball mill. The fine slurry will be directed to the froth flotation circuit, while the cyclone underflow stream will be transferred to the gravity circuit.

The flotation circuit will comprise a roughing flotation stage followed by three concentrate cleaning stages and a first stage cleaner tailings scavenger stage. The resulting copper-gold concentrate will be thickened and filter-pressed before transporting to the port of Stratoni.

Cyclone underflow from the flotation circuit will pass through the gravity concentrators to produce a final gold gravity concentrate, which will be calcined and smelted to produce gold doré bars.

Infrastructure facilities at Skouries

Power for the mining and processing plant operations is proposed to be supplied by PPC, the Greek power authority. In addition, the mine will use a 60kVA UPS system for providing a 30-minute back-up to the main control room and a 700kVA capacity emergency diesel generator as back-up in the event of power failure.

Key players involved with the Skouries mine development

“Omikron Kappa Consulting designed the tailings management facility.”

SRK Consulting prepared the technical report for the Skouries project, while URS/Scott Wilson (Scott Wilson) was engaged to update the mining study report of the project.

Golder Associates designed and conducted engineering works for the tailings paste distribution system and the tailings management facility.

Omikron Kappa Consulting designed the tailings management facility. Outotec is the supplier of the technology package for the concentrator plant.

ENOIA, an engineering contractor based in Athens, was engaged to conduct a basic engineering study and a detailed engineering study for the plant and infrastructure facilities.

NRI Energy Technology

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