Overview

Deposit type

• Porphyry

Summary:

The mineralised zones on the Cobre Panamá property are examples of copper-gold-molybdenum porphyry deposits.

Supergene mineralisation
Oxidation of sulphides near the surface weathering profile has leached copper from the present-day saprolite. Copper has been weakly and irregularly re-precipitated in the upper zones of the deposits. Secondary sulphides are dominantly chalcocite with minor covellite and rare native copper. These secondary minerals occur as fracture infills, coatings on primary sulphide minerals and disseminations. Where these sulphides have been oxidised, malachite is the main copper oxide mineral.

Notably absent across the majority of the Cobre Panamá deposits is the presence of a significant zone of enrichment. It is interpreted that this is likely due to removal by erosion of a previously welldeveloped phyllic alteration zone which may have overlain these deposits. Phyllic alteration zones are suitable host rocks for re-precipitation of copper as they can sufficiently neutralise the acidic fluids required for leaching. A well-developed phyllic alteration zone is developed at Brazo, which accompanies a significant secondary copper sulphide mineralisation zone.

Hypogene mineralisation
Hypogene mineralisation within the granodiorite and various porphyry lithologies consists of disseminated sulphides, micro-veinlets, fracture fillings, veinlets and quartz-sulphide stockworks.

Copper mineralisation occurs as chalcopyrite with lesser bornite. Throughout all deposits the proportion of bornite relative to chalcopyrite appears to increase with depth. Molybdenite is present in quartz “B” veinlets (Gustafson and Hunt, 1975). Pyrite is ubiquitous but the tenor increases in association with phyllic and chlorite-silica alteration compared to other alteration assemblages. Within the phyllic alteration zone, pyrite occurs as disseminations and within “D” veinlets (Gustafson and Hunt, 1975) with quartz. Minor specularite and magnetite mineralisation occurs as dissemination and veinlets in all deposits.

Mineralisation on the contacts between the andesite and feldspar-hornblende-quartz porphyry can reach high copper tenor in zones of biotite hornfels. Chalcopyrite is the dominant sulphide with minor pyrite and rare bornite, occurring in veinlets, blebs and disseminations. This style of mineralisation is often cross-cut by quartz-sulphide veining.

Botija
The Botija deposit is located in the northeast area of the Cobre Panamá concession. Botija is hosted in several feldspar-quartz-hornblende porphyry dykes (up to four) which range in thickness from 20 m to 200 m, and which have intruded the granodiorite and andesite host rocks. In general, the dip of the more distinct dykes is approximately 70° to the north.

Two irregular, keel shaped andesite roof pendants of approximately 500 m in diameter have been identified at Botija (Rose et al, 2012), separated by approximately 300 m and reaching depths of between 200 m to 300 m. A smaller pendant, up to 250 m along strike and extending to a depth of 150 m sits to the north of the deposit.

Colina
The Colina deposit is focused on a 3.0 km long by 1.2 km wide feldspar-quartz-hornblende porphyry sill and dyke complex (lopolith) that trends east-southeast.

The majority of the feldspar-quartz-hornblende porphyry comprises of 50 m to 200 m thick sills that dip shallowly to the north and are often interconnected by dykes.

Valle Grande
The Valle Grande deposit is located to the southeast of Colina and is 3.2 km long and 1 km wide, striking northwest-southeast. The deposit is focussed on an irregular feldspar-quartz-hornblende porphyry lopolith.

Balboa
Mineralisation at Balboa is dominantly hosted by a feldspar-quartz-hornblende porphyry that intrudes the adjacent andesite at a low to moderate angle, emanating from the north-northwest. Mineralisation is best developed in the central portion of the porphyry but weakens towards the contacts with the andesite. The porphyry can locally be described as a crowded feldspar porphyry, with variable percentages of feldspar and lesser quartz phenocrysts which range in size from 1 mm to 4 mm.

Medio
Medio is located immediately east-northeast of the Colina deposit and 2 km northwest of the Botija deposit. Drilling has delineated a 1.3 km by 800 m area of low to moderate grade porphyry mineralisation. Mineralisation is associated with silicified and sericitised porphyritic intrusive rocks and brecciated andesite volcanics. Copper tenor appears to be strongly correlated to vein and fracture intensity.

Botija Abajo
Botija-Abajo is approximately 2.5 km southeast of Botija. Drilling, completed mainly by PTC identified two deposit areas, Botija Abajo East and Botija Abajo West. Mineralisation is primarily located within feldspar-quartz-porphyry with some mineralisation extending into the andesitic tuffs.

Brazo
The Brazo deposit is located approximately 3 km south-southeast of Botija. Copper and gold mineralisation was identified in a feldspar-quartz porphyry with dominant sericite alteration. The Brazo deposit has an approximate area of 600 m by 700 m and remains open to the east, northeast and at depth.

Mining Methods

• Truck & Shovel / Loader

Summary:

The Cobre Panama concession was developed as a conventional truck and shovel open pit mine.

Mining proceeded in phases from an initial starter pit at Botija, supplying pre-strip development waste for site infrastructure construction and ore for process plant commissioning.

Prior to being placed into a period of P&SM, mining at Cobre Panama involved ultra-class scaled mining equipment and conventional open pit methods at up to approximately 83 Mbcm of ore and waste mined per annum. The multiple pits would be mined in an optimized sequence and in phases, with ore crushed in-pit and conveyed overland to the nearby processing plant.

At the end of 2021, four rope shovels, three ultraclass loaders and thirty ultraclass trucks were operating in the Botija Pit. A fifth rope shovel and eight additional ultraclass haul trucks were added to the fleet in 2022. Significant progress had been made on the pre-strip work for the Colina pit and earthworks for the associated overland conveyor and in-pit crushing facility. The overall life of mine strip ratio (tonnes) is 1:1.

Building upon the technologies developed at other FQM operations, the project featured in-pit crushing and conveying (“IPCC”). Blasted ore was hauled to IPCC installations strategically located within the open pits. These installations were near surface at the outset, but were moved deeper into the pits as mining proceeded over time. In-pit conveyors were extended as required and they converged on surface level at a central transfer station discharging to a permanent overland conveyor connecting to the plant site.

The Botija Pit was being mined first, followed by the Colina and Medio Pits. Mining in the Valle Grande and BABR Pits were planned to commence towards the end of mining of the Colina Pit, with the Balboa Pit being mined last.

Terrace mining
The mine development approach for the open pits has changed from one which was based on phased pits and cutbacks towards an ultimate perimeter, to one which is now based on a terraced mining layout. This change comes about due to experience elsewhere at Company operations, where the deployment and utilisation of ultra class mining equipment has been improved by operating on broad terraces. A terrace layout in the Cobre Panamá environment also provides an improved means of managing rainfall inundation of the pits.

Trolley-assisted haulage
Trolley-assisted haulage is a concept that is being adopted during the early life of operations. The primary truck haulage fleet is being delivered “trolley-assist ready” (TA). Additional pit ramp width has been included in the detailed pit phase designs to allow for the physical placement of transformers and catenary wire poles . In places, these ramps could be extended onto the waste dumps.

Waste dumping
The planned waste dumps (referred to as “waste rock storage facilities”, WRSF) are located surrounding the various pits, wherever space dictates, and in areas that have been largely sterilised by exploratory drilling.

The dump profiles have been designed with a 32° batter angle, a 30 m batter height, 26 m width berms, and minimum 55 m wide ramps at 1:10 gradient. The overall angle of each ultimate dump slope is approximately 22°.

Drilling and blasting
Near-surface saprolite material is being mined essentially as free-dig. As and when required, bench development that requires blasting will be blasted on bench heights of between 5 and 10 m and using small diameter blast holes.

Below this horizon, production drilling and blasting will take-place in rock conditions requiring a range of drilling/charging patterns and powder factors. Due to the mix of large and medium sized rotary drills there will be large and medium diameter holes used to blast ore and waste.

High and medium grade ore is preferentially direct fed to the crushers. However, some of this tonnage must be mined and stockpiled and hence, high and medium grade ore stockpiles are considered to be “active” throughout the mine life.

Long term low grade ore and saprock ore stockpiles are developed over the life of the mine and are not reclaimed until the final years of operations.

Mining and processing schedules
With the completion of the detailed ultimate pit designs, detailed life-of-mine (LOM) production scheduling was completed using MineSched software. Scheduling assumptions included:
• minimum mining block size (x, y, z) for Botija = 100 m x 100 m x 15 m
• minimum mining block size for all other pits = 200 m x 125 m x 15 m
• mining flitch height = 15 m
• maximum vertical advance rate = 60 to 75 m/year
• terrace mining with horizontal lag distance of 100 m to 200 m.

Comminution

Crushers and Mills

Summary:

Four in-pit semi-mobile primary crushers feed two overland conveyors to the secondary crushers and main processing complex. The three 28 megawatt SAG mills and four 16.5 megawatt ball mills installed at Cobre Panama are the largest installed anywhere in the world, except for Sentinel.

Cobre Panama’s eighth mill came on line in mid-December 2019, providing additional capacity on the third milling train.

Nine mills (three SAG mills and six ball mills) were operating prior to the suspension of operations in November 2023.

The Cobre Panama Technical Report released in March 2019 includes the plan for expansion of Cobre Panama from 85 Mtpa to 100 Mtpa starting in 2023. Construction and commissioning was completed for the CP100 Expansion project at Cobre Panama, which, prior to the suspension of Cobre Panama in November 2023, was intended to achieve a throughput rate of 100 Mtpa by the end of 2023. This included the addition of a sixth ball mill, a screening plant and process water upgrades alongside other process plant facilities and infrastructure upgrades.

Description (Technical Report, March 2019)
The initial four primary gyratory crushers located in the Botija Pit are semi-mobile in-pit installations.

The primary crushing circuit will comprise up to five semi-mobile, independent, gyratory crushers (3 x ThyssenKrupp KB 63 x 89 and 2 x ThyssenKrupp KB 63 x 130) operating in open circuit. Each crusher will be positioned in-pit and remote from the plant area, and crushed ore will be transported to the plant by an overland conveyor.

Crushed ore will be conveyed out of the pit to a surface transfer point, and thence by dual overland conveyors to where it will discharge into either secondary crusher feed bins or bypass direct via apron feeders to a coarse ore stockpile at the concentrator.

Two trains of six apron feeders feeders and conveyors will draw ore from below the coarse ore stockpile and feed two parallel wet-grinding lines, each consisting of a 28 MW semi-autogenous grinding (SAG) mill and two 16.5 MW ball mills, all equipped with gearless drives. A third train of six apron feeders and conveyors will feed to a third SAG mill linked to the other train of ball mills to maximise their usage and enable maintenance of the treatment rate whilst also being able to operate independently. By the end of 2019, the third train will be equipped with a 22 MW ball mill operating in conjunction with the 28 MW SAG mill, whilst retaining linkage to the other two trains.

The SAG mill circuits will be closed by a combination of trommel screens followed by washing screens; conveyors will deliver screen oversize to pebble crushers via metal removal systems. A dedicated system for the recycling of reject balls is provided. The pebble crushing circuits will include pebble bins, up to four cone crushers, and a bypass arrangement. Crushed pebbles will return to the SAG mills via the stockpile feed conveyors.

The pebble crushing plant is located adjacent to the secondary crushers. A parallel pebble handling circuit provides for standby and direct return of pebbles to stockpile, so as to support crusher and bin maintenance.

Discharge from each SAG mill will be cycloned to recover the finished product whilst unfinished product will be evenly split between two ball-mill circuits. The four ball-mill circuits will be closed by hydrocyclones. The finished product from all cyclones will gravitate to two surge tanks, via in-stream particle and chemical samples, prior to pumping to the flotation area.

Linked to the ball mill circuits will be two gravity gold recovery plants. A proportion of the ball mill discharge will be pumped to the two gravity gold circuits comprising scalping screens and centrifugal gravity concentrators. The centrifugal gravity concentrators will recover the free gold and direct it to a gold plant for upgrading to bullion. Tails from the gravity concentrators will be returned to the milling circuit.

Processing

• Crush & Screen plant
• Gravity separation
• Centrifugal concentrator
• Flotation
• Dewatering
• Filter press

Summary:

The predominantly copper/molybdenum sulphide ore is amenable to conventional differential flotation processing, with gold and silver recovered into the copper concentrate and also separated into a bleed stream gravity concentrate for doré. The processing plant design is based upon a conventional sulphide ore flotation circuit, with differential flotation to produce separate copper and molybdenum concentrate products. Plant tailings are directed into the tailings management facility and at a later date would be directed into the depleted Botija open pit.

The copper concentrate containing gold and silver byproducts was piped as a slurry to the port site on the northern coast of the country (on the Caribbean Sea), where it was dried in filter presses and stored before being loaded onto vessels for shipping to world markets. The molybdenum concentrate would be delivered to the port by road and shipped in bulk bags.

While design recoveries vary for each deposit the average recoveries were expected to be around 90% for Copper, 53% for Molybdenum and 56% for Gold over the life of mine.

Construction is complete for the CP100 Expansion project at Cobre Panamá to achieve a throughput rate of 100 Mtpa. This includes the addition of a sixth ball mill, a screening plan and process water upgrades alongside other process plant facilities and infrastructure upgrades. These facilities are currently in commissioning and ramp up will now continue over the course of the year to achieve a throughput rate of 100 Mtpa by the end of 2023.

The molybdenum plant equipment was delivered to site in 2022 and is expected to be installed during 2023. Molybdenum in concentrate production is expected in the range of 3-4 ktpa.

Process description
Aside from in-pit primary crushing, the processing plant will include conventional facilities, such as:
- crushing (secondary and pebble) and grinding (SAG/ball) to liberate minerals from the ore;
- froth flotation to separate most of the copper and molybdenum minerals from minerals of no commercial worth;
- differential flotation to separate the copper and molybdenum minerals from each other;
- storage of tailings and provision of reclaim water for the process;
- removal of water from the products.

The process plant is designed to process ore at a head grade of up to 0.65% Cu and 0.023% Mo. These levels are higher than the highest sustained head grades of 0.46% Cu and 88.40 ppm Mo scheduled to be mined in 2023 and 2029, respectively, but the design provides the flexibility to accommodate a wide range of head grades over the Project life.

Flotation
Ground slurry will be directed to a flotation circuit where a bulk sulphide concentrate, containing copper, molybdenum, gold and silver values, will be collected and concentrated in a rougher followed by cleaner flotation. A primary high grade concentrate from the first rougher cell will be collected and cleaned directly in columns to produce a final product. The balance of concentrate from the remainder of the rougher cells will be collected, fed into three regrind mills, and then cleaned in two stages of mechanical cells followed by a one column stage to produce a final bulk concentrate.

The rougher and cleaner circuits will be installed to meet ultimate capacity, with no further additions required.

The bulk concentrate will be thickened in conventional thickeners (with no flocculant) and pumped to a differential flotation plant, where copper minerals will be depressed, and molybdenite floated into a molybdenum concentrate.

Concentrates
Copper/gold concentrate piped from the plant site will be filtered, reclaimed using a mechanical reclaimer and loaded by closed conveyors on to bulk ore carriers. The filtrate water will be treated at the port in a water treatment plant or aternatively pumped through a return pipeline to the TMF. The concentrate will be filtered in automatic filter presses and when dry (8% to 9% moisture), will be stored in a covered building with a capacity of 140,000 t.

The molybdenum concentrate will be filtered, dried, and packaged in containers for shipment to offshore roasters. Tailings from the molybdenum flotation circuit will constitute the copper concentrate, which will be thickened/pumped/piped approximately 25 km to a filter plant at the Punta Rincón port site. If the molybdenum head grade is unsuitable, the molybdenum separation plant can be readily bypassed.

Tailings disposal and process water reclaim
For the first approximate fourteen years of the operation, tailings containing silicate, iron sulphide and other minerals from the rougher and cleaning steps will be deposited into the TMF located north of the mine and plant. The TMF is of centre line/downstream construction.

The plant is equipped with preparation facilities for all required liquid and solid reagents, including frother, collector, promoter and lime. In addition, a ball charging system is provided in the milling area for feeding balls into the respective mills.

Pipelines and Water Supply

Summary:

Potable water for the Project, including the port site, is obtained from local rivers and treated prior to distribution.

During operations, process water will be reclaimed from the TMF and collected from pit dewatering and surface drainage ponds. Water from the TMF will be pumped to the plant site by barge pumps followed by two stages of booster pumps.

A seawater intake and discharge has been constructed at the port site to supply the power plant.

Pipelines
Concentrate, concentrate filtrate return water, and fuel pipelines have been installed on surface between the plant and port site. These are located along the side of the coast access road.

The process plant requires a number of large pipelinesfor water and tailings management. The tailings lines (ie, six lines currently, with additional required as the Project expands) run alongside the coast access road from the plant area to the north east corner of the TMF. At this point they pass through a cyclone station and split onto the TMF walls.

Production

Operational metrics

Personnel

Job Title	Name	Profile	Ref. Date
Chief Engineer	Ravi Pillay		Jul 3, 2024
Electrical Superintendent	Boris Ostap Batista Jaramillo		Jun 12, 2024
Environmental Superintendent	Agustina Inés Varela		Jun 12, 2024
General Manager	Alan Delaney		Jun 12, 2024
Materials & Logistics Superintendent	Zafer Unlu		Jun 12, 2024
Mill Superintendent	Joseph Kasaji		Jun 12, 2024
Mine Development Manager	Japie Vorster		Jun 12, 2024
Mine Technical Manager	Randy Van Order		Jun 12, 2024
Process Plant Manager	Okan Altun		Jun 12, 2024
Procurement Superintendent	Carlos Velasco		Jun 12, 2024