Porphyry copper–gold systems host some of the most widely distributed mineralisation types at convergent plate boundaries, including porphyry deposits centred on intrusions; skarn, carbonate-replacement, and sediment hosted gold deposits in increasingly peripheral locations; and high to intermediate-sulfidation epithermal deposits.

The alteration and mineralisation in porphyry copper–gold systems are zoned outward from the stocks or dyke swarms, which typically comprise several generations of intermediate to felsic porphyry intrusions. Porphyry copper (± gold, ± molybdenum) deposits are centred on the intrusions, whereas carbonate wall rocks commonly host proximal copper–gold skarns, less common distal zinc–lead and/or gold skarns, and, beyond the skarn front, carbonate replacement copper and/or zinc–lead–silver (± gold) deposits, and/or sediment-hosted (distal-disseminated) gold deposits. Peripheral mineralisation is less conspicuous in non-carbonate wall rocks but may include base metal-bearing or gold-bearing veins and mantos (Sillitoe, 2010). Skarn deposits are typically hosted in mineralogically simple finegrained clastic and carbonate sedimentary rocks. Skarn mineralogy and metal content is largely dependent on the crystallisation history and genesis of associated plutons (Meinert et al., 2005).

The Çöpler district is located near the north margin of a complex collision zone and to the south of the prominent North Anatolian Fault Zone. The Çöpler district deposits (Çöpler, Çakmaktepe, Ardich, and Bayramdere) are hosted within the Tethyan mineralised belt, a major global mineralised terrain for gold, copper, and base metals.

COPLER DEPOSIT
The Çöpler deposit is centred on composite diorite to monzonite porphyry stocks that are part of the Eocene Çöpler Kabatas magmatic complex dated. Metamorphic rocks of the Permian to Upper Cretaceous Keban formation shelf sequences vary in composition between siliciclastic and calcareous, with fine to medium-grained sandstone interbedded with mudstone, and locally thick sections of fine laminated mudstone. The sedimentary units are folded with a resolved fold axis plunging at approximately 25-200 (plunge-plunge direction) from bedding measurements in the Çöpler pits.

The Çöpler intrusion is a hornblende–quartz diorite-porphyry that shows strong argillic alteration. Some fresh outcrop occurs in the central part of the Main Zone and also as remnants within the Manganese Zone. In its least-altered state, the diorite-porphyry is relatively pristine with well-preserved hornblende, biotite, and K-feldspar phenocrysts in a granular matrix of plagioclase and quartz with prominent magnetite. Three mineralisation styles at Copler deposit:

- Low-Grade Porphyry Vein Mineralisation: characterised by well-developed alteration zones that are complex and superimposed on each other; late-stage porphyry mineralisation is hosted in diorite-tonalite porphyry as dominant sheeted veinlet arrays and as stockworks in metamorphic wall rocks and intruded into a low-grade to barren diorite porphyry system.

- Intermediate Sulfidation Epithermal Mineralisation: primarily observed in the Manganese pit as clusters of bright pink, banded, colloform, rhodochrosite base metal sulfide veins and breccia lodes, with a spatial association with elevated gold grades; carbonate base metal veins contain base metal sulfides sphalerite±galena±chalcopyrite in a gangue of calcite, ferroan dolomite, and/or manganese carbonates (rhodochrosite) or realgar.

- Iron Skarn and Carbonate Replacement Mineralisation: developed along faults, shear zones, and within karstic spaces. It is observed as iron oxide-rich zones as well as gossan-like and jarosite formations developed by oxidation of previous pyrite-rich mineralisation; this replacement type mineralisation appears to be derived from previously formed distal skarn mineralisation.

CAKMATEPE DEPOSIT
The Çakmaktepe deposit is made up of a number of mineralised zones. The deposit area mainly comprises various Palaeozoic metamorphic rocks and marbles belonging to the Keban formation that constitute the basement and Mesozoic platform carbonates (e.g. Munzur limestone).

The Çakmaktepe deposit is a structurally controlled gold–silver–copper deposit, displaying both epithermal and replacement mineralisation styles. Mineralisation is primarily associated with jasperoid and listwanite. At depth, mineralisation transitions below the base of oxidation to disseminated pyrite, vein sulfides, and massive sulfide horizons, generally occurring within shear zones, along shallow thrusts, in diorite sills, and on intrusion margins.

Çakmaktepe is considered to be the result of a mineralised intrusion that generated suitable conditions for mineralisation to be localised into a favourable geological setting of ophiolite, limestone, and hornfels lithologies. A complex system of faults and thrusts have allowed mineralised fluids and diorite dykes and sills associated with the epithermal system to permeate into the stratigraphy. Steep-dipping, shear-hosted mineralisation is characterised at Çakmaktepe North, whereas flatter, earlystage, thrust-related mineralisation is characterised at Çakmaktepe East, Çakmaktepe South-East and Çakmaktepe Central. Key to each structurally associated style of mineralisation is the juxtaposition of ophiolites against limestone and hornfels to create the right geochemical conditions for the deposition of gold and other metals.

ARDICH DEPOSIT
The Ardich deposit is located immediately to the north-west of the Çakmaktepe deposit. The north-western portion of Ardich and the Çakmaktepe North mineralised zone are in close proximity to each other, as are the Ardich Southeast and Çakmaktepe East mineralised zones. While there are some characteristic differences between Ardich and Çakmaktepe, the local geology is generally very similar.

The mineralisation at Ardich occurs at a higher stratigraphic level that that seen at Çakmaktepe. The emphasis at Ardich is on the ophiolitic mélange rocks that have been thrust into place on top of the basement metasediment and carbonate lithologies. The local geology at Ardich is dominated by ophiolites, listwanite, and dolomites and limestones, with mineralisation occurring along low-angle thrust zones between ophiolites, listwanite, and dolomites and limestones. This occurs within a complex northwest trending structural zone that is cut by multiple high-angle faults that together result in creating multiple rotated fault blocks and mineralised zones.

BAYRAMDERE DEPOSIT
The Bayramdere deposit is an oxide gold and copper deposit with similar geological and mineralisation characteristics to the Çakmaktepe and Ardich deposits. The geology is dominated by ophiolites that have been thrust over the limestone and dolomite, which are in turn intruded by granodioritic stocks. Gossans are generally observed as lenses and confined by normal faults. The Bayramdere mineralisation is localised within three stacked, shallow-dipping lodes that have formed at the contacts of limestone and ophiolite lithologies, with mineralisation replacing limestone along the contacts. The limestone/ophiolite contacts are low-angle thrusts, with limestone typically being trapped as wedges of material within a dominantly ophiolite stratigraphy. Mineralisation occurs within shallow iron-rich gossan horizons.

COPLER SADDLE DEPOSIT
Along the shear zone, the geology is dominated by limestone, marble, and hornfels units that are in turn intruded by small-scale microdioritic to granodioritic stocks. These lithologies were subjected to silica-clay alteration with iron oxide developments along the local structures as well as clay-pyrite alteration. At the south of the zone, silica is mainly observed as jasperoid lenses, of approximately 2 m long and 1 m wide, which occur along the hornfels and marble contacts.

Open pit mining at the Çöpler project is carried out by a mining contractor and managed by Anagold. The mining method is a conventional open pit method with drill and blast and utilising excavators and trucks operating on bench heights of 5 m. The mining contractor provides operators, line supervisors, equipment, and ancillary facilities required for the mining operation. SSR provides management, technical, mine planning, engineering, and grade control functions for the operation. SSR currently operates a sulfide process plant and an oxide heap leach facility.

New pit designs were created in 2021 based on updated metal prices and costs.

The key aims of the optimised pit designs are:

• Minimise mining costs and maximise economic return by exposing the highest value ore with minimum waste mining.

• Address operational requirements for loading, hauling, slope stability, and rockfall, as follows:
- Loading – the phases were designed with a minimum operational width of 15–30 m between phases (depending on bench configuration) to allow efficient mining for the equipment scale.
- Hauling – generally, two exit haul roads per phase were included: the west bound exit to the crusher, low-grade stockpile, and west dump; and the east bound exit to the potentially acid forming (PAF) and non-acid forming (NAF) dumps. Haul roads are generally 15 m wide at a 10% gradient. Single-lane haulage traffic is allowed in the lower benches of the mine and is set at 10 m wide.

Pit designs for the Çöpler pit were updated in 2021. Ardich pit designs were prepared in 2021 and updated in 2022. The Çöpler, Ardich, and Çakmaktepe pit design for 2034, when in-pit mining is completed for the Reserve Case. Following completion of inpit mining, the sulfide plant will be fed from stockpiles until 2043.

Crushing and Ore Handling
Haul trucks from the mine tip ore onto designated stockpile fingers. The ore is withdrawn from stockpiles by front end loader (FEL) and deposited into the run-of-mine (ROM) dump hopper. A static grizzly is fitted to the top of the ROM bin to remove coarse oversize.

ROM ore is reclaimed from the bin by the sizer apron feeder, which discharges material into the mineral sizer. The sizer is a tooth roll unit which crushes the ore from a feed top size of 500 mm to a nominal top size of 250 mm. Discharge from the sizer drops down a chute onto the sizer discharge conveyor.

The sizer teeth are configured in a manner to direct oversize rocks to one end where they pass through a spring-loaded oversize rejection gate and fall to a reject bunker. The crushed product is carried by the sizer product conveyor to the semi-autogenous grind (SAG) mill feed conveyor. The SAG mill feed conveyor has a belt scale to monitor the ore flow to the SAG mill and this information is used to control the sizer apron feeder speed.

Grinding
The SAG milling stage consists of a high aspect SAG mill with water cannon pebble recycle. The SAG mill grinds the crushed ore to produce a discharge particle size distribution P80 of approximately 1,400 µm.

Large ore particles are retained in the SAG mill by the internal SAG discharge grate. Particles too large for ball milling are retained as oversize on the SAG mill trommel screen and this oversize is washed by trommel sprays. The trommel screen oversize is either projected back into the SAG mill using a high-pressure water cannon or rejected via a conveyor. Slurry that passes through the trommel screen discharges into the grinding cyclone feed pump box where it mixes with the ball mill discharge slurry and density control water.

Slurry collected in the grinding cyclone feed pump box from the SAG mill and ball mill is fed to the grinding cyclone cluster. The cyclones produce an overflow product with a P80 of 100 µm, which is screened to remove any trash (organic material, etc.) by the grinding trash screen. Coarse particles report to cyclone underflow, which is returned to the ball mill for further size reduction until it is fine enough to report to cyclone overflow and leave the circuit.

SULFIDE ORE PROCESSING
The incorporation of a flotation circuit into the existing sulfide plant to upgrade sulfide sulfur (SS) to fully utilise grinding and pressure oxidation (POX) autoclave capacity has completed construction and commenced commissioning on ore in January 2022. This addition to the sulfide plant is incorporated between grinding and acidulation, by taking a bleed / slip stream from the grinding thickener feed, floating sulfides, and returning the sulfide concentrate to the grinding thickener to be combined with direct feed. Gold not recovered to flotation concentrate will report with flotation tails to the gold leaching and recovery circuit and combined with material process through the POX autoclave circuit to recover gold.

The flotation circuit will also reject carbonates to flotation tails, bypassing acidulation and POX, providing additional benefits in the acid balance through POX.

The existing sulfide circuit, before the addition of flot ........