MineGuessr – Skouries, Greece: High-Grade Copper-Gold Porphyry

MineGuessr Advent Calendar 2025 – Door 6

Skouries is one of the mines featured in our 2025 MineGuessr mining advent calendar. Each December day, we reveal a new mining satellite timelapse and invite you to guess the mine from satellite imagery of mines across Europe and the Nordics.

On this page, we provide a concise, professional overview of Skouries – its location, geology, development history and role in the raw materials value chain. The satellite timelapse is unusual in the series: you’re not watching a mature open pit grow, but a high-grade copper–gold porphyry project move through years of permitting, construction, suspension and restart – before first ore has even been mined.

Satellite view of the Trimouns talc quarry above Luzenac in the French Pyrenees for the MineGuessr mining advent calendar

Overview & location

Skouries is a high-grade copper–gold porphyry deposit located in the Kassandra Mines complex on the Halkidiki Peninsula in northern Greece. The project is owned by Eldorado Gold, through its subsidiary Hellas Gold, and is being developed as a combined open pit and underground operation with a planned initial life of mine of around 20 years.

Based on the 2021/2022 Feasibility Study, Skouries is expected to produce on average about 140,000 ounces of gold and 67 million pounds of copper per year over the life of mine, with first concentrate production targeted for early 2026.

Where in the world is Skouries?

Region: Central Macedonia, northern Greece, in the Chalkidiki (Halkidiki) peninsula.
Municipality: Aristotelis; near the village of Megali Panagia, roughly 100 km east of Thessaloniki.
Elevation: About 350–620 m above sea level on forested hills within the Kassandra concession.

From above, Skouries appears as a compact cleared area and early earthworks in the middle of dense forest, with a boxcut, initial open-pit shell, underground portals and the footprint of an Integrated Waste Management Facility (IWMF) where filtered tailings and waste rock will be co-disposed in a valley setting.

Geology & deposit type

Skouries is a classic copper–gold porphyry deposit hosted in the Serbo-Macedonian Massif:

The orebody is centred on a near-vertical, pencil-shaped monzonite–syenite porphyry stock that intrudes schists and gneisses of the Vertiskos Formation.
Mineralisation occurs in stockwork veinlets and disseminations, with strong potassic alteration (biotite–K-feldspar) overprinting the host rocks.
Reserves and resources indicate a high-grade porphyry for Europe: combined proven + probable mineral reserves have been reported around 0.7–0.8 g/t Au and 0.5% Cu, supporting a multi-decade mine life.

In the context of MineGuessr, Skouries represents the “deep porphyry pipe” end of the calendar – contrasting with shallow, bulk-tonnage operations like Aitik or industrial mineral quarries such as Trimouns.

What the mining satellite timelapse shows

The mining satellite timelapse for Skouries (1984–2022) is very different from most other doors in the calendar. There is no mature open pit yet and no long tailings history. Instead, you see how a greenfield porphyry project gradually appears in the forest, pauses, and then restarts as permits, financing and social licence evolve.

1980s–early 2000s – exploration in a forested landscape

The hills around Skouries have a long mining history at the district scale, but at the actual deposit footprint, satellite images from the 1980s and 1990s show continuous forest cover with only minor access tracks.
During these decades, work is mainly sub-surface exploration – drilling and geological studies – rather than major earthworks visible from space.

On the timelapse: the Skouries door is one of the few where “nothing happens” for a long time – a reminder of how much permitting and feasibility work is invisible from orbit.

2000s–early 2010s – approvals and early construction

In 2011, the Environmental Impact Study for the Kassandra Mines (including Skouries) is approved by the Greek government, and development work starts.
By the early 2010s, Eldorado and its predecessor companies clear forest, build roads, prepare the plant site and start boxcut / starter pit works.

On the timelapse: you’ll see the first clearings in the forest, a road network, benches cutting into the hillside and the initial footprint of the process plant and IWMF.

2015–2019 – suspensions, care & maintenance and partial build-out

From 2015–2017 there are significant permitting and legal disputes; Eldorado suspends construction at Skouries and places the project on care and maintenance in 2017 due to delayed environmental permits.
Limited site work continues to keep the partially built facilities safe, but the overall footprint grows slowly compared with the earlier construction push.

On the timelapse: the disturbed area “freezes in time” – you see a partly developed pit shell and plant site, but no obvious major new pushbacks or tailings cells like in long-running operations.

2020s – financing, restart and toward first production

Following a new investment agreement with Greece and a 2021 Feasibility Study, Eldorado secures a project financing facility and fully restarts construction in 2023.
By late 2025, Skouries construction is reported to be around 70–73% complete, with first copper-gold concentrate production expected in early 2026 and commercial production later in the year.

In the last frames of the 1984–2022 timelapse, you mainly capture the “restart phase”: expansion of the plant area, shaping of the IWMF embankment and more defined pit and underground portals – but still pre-production.

Mining method & processing – how the ore will move

Skouries is designed as a two-phase operation with a combination of open pit and underground mining:

Phase 1: approximately nine years of combined open pit and underground mining, with total mill feed around 8.0 Mtpa.
Phase 2: about eleven further years of underground-only production as the pit is completed and underground stopes continue at depth.

Open pit: conventional truck-shovel operation with drill-blast, loading and haulage from a steep-sided porphyry pipe constrained by environmental boundaries and a crown pillar to protect the underground mine.
Underground: longhole stoping from multiple levels accessed via ramps and shafts beneath the pit.
Processing: crushing, grinding and flotation to produce a copper–gold concentrate; filtered tailings and selected waste rock directed to the Integrated Waste Management Facility.

Role in the raw materials value chain & energy transition

Skouries is one of the few new copper–gold porphyry projects advancing in the European Union. When in production, it will:

Provide gold and copper supply within the EU, supporting industrial value chains that currently rely heavily on imports.
Contribute copper for power grids, electric vehicles and renewable-energy infrastructure – core sectors in the energy transition raw materials narrative.
Serve as a test case for how large, contentious greenfield projects can be developed under modern European ESG and permitting expectations.

For MineGuessr, Skouries is also a reminder that energy transition raw materials do not come only from legacy, decades-old open pits – they also depend on new, sometimes controversial projects being permitted and built.

What to look for in the MineGuessr timelapse

As a MineGuessr player, here are a few clues that you’re looking at Skouries:

A long period (1980s–2000s) where the area is almost fully forested, followed by a sudden, compact clearing on a ridge.
The appearance of a small, steep-sided pit shell and boxcut, rather than a sprawling open pit.
A growing IWMF footprint in a valley near the plant site, but no large, flat tailings beach like you see at Aitik or Kemi.
A project that looks “half-built” for much of the 2010s as construction stops and restarts – one of the best visual examples in the calendar of how permitting and politics show up in satellite imagery.

MineGuessr perspective – why this mine was included

We selected Skouries for the MineGuessr mining advent calendar because it:

Showcases a high-grade copper–gold porphyry deposit in the EU, contrasting with Nordic iron ore, talc and industrial mineral operations featured on other days.
Provides a visual case study of greenfield development, suspension and restart – something rarely seen so clearly in satellite timelapse.
Raises useful questions about ESG, social licence and long-term planning in forested, tourism-sensitive regions.

In our GeoGuessr-style mine guessing game, Skouries helps spark conversations about porphyry copper–gold deposits, project development risk and modern EU mining policy.

Throughout December, keep opening a new door every day and explore all 24 mines featured this year on the main MineGuessr mining advent calendar page.

Day 1 - Aitik (Sweden, copper-gold open pit)
A large, low-grade copper operation south of Gällivare
👉 Open Door 1 - Aitik
Day 2 - Björkdal (Sweden, gold)
Gold mine near Skellefteå, combining open-pit and underground mining.
👉 Open Door 2 - Björkdal
Day 3 - Kemi (Finland, chrome)
Chrome mine in northern Finland, Europe’s only chromite operation.
👉 Open Door 3 - Kemi
Day 4 - Ørtfjell (Norway, iron ore)
Iron ore mine in Norway’s Dunderland Valley, evolving from large open pits to underground mining.
👉 Open Door 4 - Ørtfjell
Day 5 - Trimouns (France, talc)
World’s largest working talc quarry high in the French Pyrenees above Luzenac.
👉 Open Door 5 - Trimouns
Day 7 - Las Cruces (Spain, copper)
High-grade hydromet copper mine in the Iberian Pyrite Belt north-west of Seville.
👉 Open Door 7 - Las Cruces
Day 8 - Assarel–Medet (Bulgaria, copper)
Twin porphyry copper open pits in the Panagyurishte district, from Europe’s former largest open-pit copper mine at Medet to today’s modern Assarel operation.
👉 Open Door 8 - Assarel–Medet
Day 9 - Glomel (France, andalusite)
World-class andalusite open-pit quarry in Brittany’s Montagnes Noires, supplying refractory minerals for Europe’s steel, foundry, cement and glass industries.
👉 Open Door 9 - Glomel
Day 10 - Parnassos–Ghiona (Greece, bauxite)
Karst-type bauxite mines in the Parnassos–Ghiona mountains, a historic alumina feedstock district supplying Greece’s aluminium industry.
👉 Open Door 10 - Parnassos–Ghiona
Day 11 - Kittilä (Finland, gold)
Europe’s largest primary gold mine at the Suurikuusikko orogenic gold deposit north of the Arctic Circle.
👉 Open Door 11 - Kittilä
Day 12 - Oltenia Energy Complex (Romania, lignite)
Cluster of large open-pit lignite mines and mine-mouth power plants in Gorj County, now at the centre of Romania’s coal phase-out and just transition plans.
👉 Open Door 12 - Oltenia Energy Complex
Day 13 - Cornwall china clay (UK)
Historic Imerys china clay pits near St Austell, where bright white kaolin benches and tips reshape “Clay Country” over decades of mining and restoration.
👉 Open Door 13 - Cornwall china clay
Day 14 - Aggeria–Agia Irini (Greece, bentonite)
Overlapping bentonite open pits on the volcanic island of Milos, anchoring one of Europe’s key industrial minerals districts.
👉 Open Door 14 - Aggeria–Agia Irini
Day 15 - Skouriotissa (Cyprus, copper & hydromet)
Ancient copper mining district in the Troodos ophiolite, now a hydrometallurgical hub processing copper, gold and battery-metal feed.
👉 Open Door 15 - Skouriotissa
Day 16 - Tunstead (UK, limestone & cement)
The UK’s largest limestone quarry near Buxton, feeding an integrated lime and cement works with long-term restoration and biodiversity plans.
👉 Open Door 16 - Tunstead
Day 17 - Narva (Estonia, oil shale)
Large open-pit oil shale mine in Ida-Viru County, supplying the Narva power plants and reshaping the landscape with strip mining and reclamation.
👉 Open Door 17 - Narva
Day 18 - Sydvaranger (Norway, iron ore)
Arctic banded iron formation at Bjørnevatn near Kirkenes, evolving toward DR-grade magnetite for Europe’s green steel transition.
👉 Open Door 18 - Sydvaranger
Day 19 - Kevitsa (Finland, nickel–copper–PGE)
Multimetal open-pit mine in Finnish Lapland, combining Ni–Cu–PGE production with trolley-assisted haulage for lower-emission mining.
👉 Open Door 19 - Kevitsa
Day 20 - Styrian Erzberg (Austria, iron ore)
Terraced “pyramid” open-pit iron ore mine at Eisenerz, turning 12 Mt of rock into ~3 Mt of ore each year for Austria’s steel industry.
👉 Open Door 20 - Styrian Erzberg
Day 21 - Minas de Alquife (Spain, iron ore)
Europe’s largest open-pit iron ore mine in Granada, restarting in 2020 after two decades of closure to supply high-grade ore to European steelmakers.
👉 Open Door 21 - Minas de Alquife
Day 22 - Siilinjärvi (Finland, phosphate)
EU’s only operating phosphate mine in central Finland, mining an Archean carbonatite for fertiliser-grade apatite and creating distinctive pale tailings and phosphogypsum stacks.
👉 Open Door 22 - Siilinjärvi
Day 23 - Tellnes (Norway, ilmenite/titanium)
World-class ilmenite open pit in the Rogaland Anorthosite Province, supplying TiO₂ pigment feedstock from one of Europe’s largest titanium deposits.
👉 Open Door 23 - Tellnes
Day 24 - Elatsite (Bulgaria, copper–gold porphyry)
High-altitude porphyry copper–gold open pit in Bulgaria’s Srednogorie zone, with ore conveyed under the Balkan Mountains to a separate flotation–tailings complex.
👉 Open Door 24 - Elatsite

About Gosselin Mining

At Gosselin Mining, we work extensively with porphyry copper–gold projects and long-life open pit/underground combinations – from trade-off studies and cut-off grade optimisation to integrated waste and tailings strategies and ESG-driven mine design. If you would like to:

Stress-test your own life-of-mine plan for a porphyry copper–gold project,
Benchmark European project assumptions against international peers, or
Discuss how satellite imagery and timelapse can support stakeholder communication,

…you’re very welcome to book a meeting with us.