Summary

Deposit type

• Manto
• Vein / narrow vein
• Carbonate replacement
• Epithermal

Summary:

The Project is underlain by sedimentary and metasedimentary stratigraphy ranging from Paleozoic to Tertiary age. It hosts several styles of mineralization within numerous deposits, zones, and target areas.

Zinc-Lead-Silver Zone Mineralization
Zinc-lead-silver mineralization within the Ayawilca deposit, referred to as the Zinc Zone, is predominantly hosted within limestones of the Pucará Group. The Zinc Zone mineralization is complex in form, made up of multiple lenses or “mantos”, sub-vertical “pipes”, and irregular sulphide bodies all consisting of semi-massive to massive zinc-rich sulphides. There are four defined areas of mineralization that are modelled separately: West, South, Central, and East.

At West Ayawilca, Zinc Zone mineralization appears to have been controlled by the axis of an anticline fold that parallels and lies just to the east of the Colquipucro Fault. Two subvertical breccia bodies or “pipes” host zinc mineralization within the hinge of the anticline, each with diameters of between 100 m and 150 m, and extend through the entire limestone sequence (up to 200 m vertically). Within the breccia bodies, zinc-rich sulphide mineralization occurs in the matrix of the breccias and typically forms semi-massive sulphides.

At South Ayawilca, continuous massive zinc-rich sulphide mineralization is concentrated within a recumbently folded (overturned) anticline that verges to the west. The South area represents the highest-grade area of zinc mineralization discovered at Ayawilca to date. Zinc mineralization takes the form of a series of stacked sulphide mantos plunging to the northeast (parallel to the 060 Fault).

Silver Zone Mineralization
Silver-rich mineralization with accompanying lead-zinc at Ayawilca occurs on the edges of the Zinc Zone and is associated with abundant hydrothermal carbonate and quartz and lesser quantities of sulphides. Silver Zone mineralization consists of manganese-rich siderite, quartz, sphalerite, galena, and pyrite with silver-bearing sulphosalts such as proustite (and other “ruby silver” minerals).

Tin Zone Mineralization
Tin mineralization at Ayawilca, referred to as the “Tin Zone”, consists of three styles:
• Cassiterite-pyrrhotite-pyrite-marcasite-siderite mineralization is hosted within a flat-dipping manto at South Ayawilca. This style of tin mineralization, which contains coarsely crystalline cassiterite, lies close to and is partly encapsulated by the Zinc Zone mineralization at South Ayawilca.
• Cassiterite-pyrrhotite-quartz-tourmaline-chalcopyrite mineralization is hosted within flatdipping mantos at Central Ayawilca. These mantos, which are typically 5 m to 10 m in vertical thickness (but may be up to 50 m in thickness), occur at the contact of the Pucará Group limestones and the Excelsior Formation phyllite.
• Cassiterite-pyrrhotite-quartz-chalcopyrite veinlets that intersect Excelsior Group phyllites comprise the third type of tin mineralization occurring at Ayawilca. This style of mineralization is a minor component of the Tin Zone currently delineated at Ayawilca, however, the veinlets are interpreted as a stockwork zone potentially close to a feeder structure that has not yet been identified.

Colquipucro Silver Mineralization
The Colquipucro silver deposit is hosted primarily within quartz sandstones of the Middle Goyllar Formation, with mineralization at or close to the surface. Silver mineralization at Colquipucro is oxidized, occurring with abundant iron oxides (goethite, jarosite) and manganese oxides in fractures and disseminations within pore spaces and fracture zones with no (or rare) sulphides.

Deposit Types
Ayawilca Zinc Zone and Tin Zone Deposits The regional setting, geometry, and zinc mineralogy indicate that the Zinc Zone and Tin Zone of the Ayawilca deposit are CRDs, of which there are several other examples in central Peru (e.g., Cerro de Pasco, Morococha, Colquijirca, and San Gregorio). These deposits typically develop when hydrothermal fluids replace carbonate rocks proximal to an intrusive body, although in some cases the causative intrusion is distal or is not observed. CRDs are considered more distal from the source than porphyry and skarn deposits, and closer to the source than intermediate- (or low-) sulphidation epithermal precious metals deposits.

The Ayawilca deposit differs from most of the other CRDs in central Peru in that there is a documented early-stage tin (copper) mineralization event associated with pyrrhotite. The QP notes that early pyrrhotite is reported at the Cerro de Pasco deposit and contained anomalous tin; however, it was not as well developed as at Ayawilca.

Another important precursor to the mineralization at Ayawilca is the pervasive magnetite (together with chlorite and minor calc-silicates) that predates all sulphide mineralization and was extensively developed across the deposit. It presently exists only in relatively restricted lower-grade Zinc Zones at the South and West Ayawilca areas. The East Ayawilca area contains a substantial body of magnetite that appears in geophysical data as a prominent magnetic anomaly.

Ayawilca Silver Zone Deposit and Colquipucro Deposit
The Silver Zone at Ayawilca is interpreted as an intermediate sulphidation epithermal vein system that cuts both the tin mineralization (earliest) and the zinc-rich mineralization at South Ayawilca. Textures displayed by the carbonate-sulphide veins suggest banding and deposition within open space, typical of low temperature epithermal mineralization that likely formed as the hydrothermal system cooled.

The Colquipucro deposit is a sandstone-hosted disseminated silver deposit with silver hosted in fractures, faults, and veins with abundant iron oxides (goethite, jarosite) and as disseminations within the pore spaces of the sandstones. The Colquipucro deposit is tentatively classified as an intermediate sulphidation epithermal deposit that became oxidized above a paleo water table. It is interpreted that Colquipucro is an oxidized form of the Silver Zone mineralization, that is, sulphides at Colquipucro have almost completely oxidized to Fe oxides and manganese-rich iron carbonates are altered to Mn-Fe oxides.

Mining Methods

• Longhole open stoping
• Transverse open stoping
• Longitudinal open stoping

Summary:

The PEA mine plan considers an owner-operator underground operation targeting a production rate of 2.0 Mtpa for the Zinc and Silver Zones, and 0.3 Mtpa for the Tin Zone for an overall runof-mine (“ROM”) production rate of 2.3 Mtpa.

The near surface Zinc Zone deposits from South and West areas are planned to be mined initially and individually accessed through decline boxcuts with truck haulage to the ROM stockpile located at the process facility. The Silver Zone and upper Tin Zone are also mined and hauled by truck to surface through these decline accesses. In the later stages of the mine life, the Central and East areas of the Zinc Zone and deeper Tin Zone will be accessed via a separate decline boxcut developed from the northern side of the mine site.

The mining method selected for the Zinc and Tin Zones is overhand longhole open stoping (“LHOS”) with paste backfill in a transverse direction which requires development across the strike of the mineralized body. This is mainly due to wider sections with a sub-vertical dip and also shallow dipping geometry of the mineralized deposits. Level waste development is required to provide a means of access from the decline (typically in the footwall) for mining mineralized areas identified as economically mineable.

For the Silver Zone, longitudinal LHOS is applied due to the relative narrow width and sub-vertical dip of the mineralized body which requires development along the strike of the mineralized body.

A level spacing of 15 m is applied for the Zinc Zone (South, West and Central areas) and Tin Zone and a 20 m level spacing is applied for the Zinc Zone (East area) and Silver Zone based on the mineralized body geometries and impact of dilution. The overhand LHOS method requires working on top of (and next to in wider areas) filled stopes and between sill pillars which are recovered at a later stage on retreat.

An access drive profile of 4.5 m (width) x 4.5 m (height) was applied which is sufficient in dimensions for the range of equipment types required for the narrow and wide LHOS mining. The drive profile reduces the maximum vertical drill height to 11.5 m for 15 m level spacing and 15.5 m for 20 m level spaced stoping areas.

Slot raises are initially drilled followed by rings of blast holes which can be either up or down holes (depending on access). Slot raises are blasted initially followed by rings into the void created by the slot.

The blasted stope material can be removed on the lower level by tele-remote methods or limited to the stope brow if the loader is being operated manually. Once the individual stopes have been excavated to their open stope limits, a barricade is installed at the stope access and the stope void is filled with paste backfill and/or unconsolidated waste, depending on the location and sequence of mining. After the paste backfill has cured sufficiently, adjacent stopes along strike or above the previously mined stope can be mined using a similar sequence.

Mine Design
The Ayawilca mine design considers individual boxcuts and declines to access each of the zones that contributes to the ROM Inventory. LHOS open stopes are based on 15 m and 20 m level spacing and mined transverse for widths greater than 15 m. The Silver Zone is mined longitudinal to strike due to its narrow width. Transverse stopes are mined through transverse drives spaced 15 m and connected to a footwall drive, while longitudinal stopes are mined through longitudinal drives connected to the decline access through cross-cut drives.

Maintaining high truck productivity in high tonne-kilometre (tkm) operations is of primary importance. Truck productivities assume loading directly from the stockpile to minimize truck idle time. The production stockpiles have been located as close as possible to the centroid of the stoping panels wherever possible.

Mine Production
Twin boom jumbos will be used for development and longhole drill rigs will be used in the LHOS production areas. Conventional diesel-powered 17 t capacity loaders and 50 t capacity haul trucks will be used to move all mine waste to the respective designated surface and underground storage and ROM to surface stockpiling areas for mineral processing.

Production is assumed to commence following 18 months of construction and commissioning. The mine plan for the Zinc and Silver Zones is based on mining a total of 41.2 million tonnes grading 5.02% Zn, 17.3 g/t Ag and 0.19% Pb over a 21-year life of mine (“LOM”) using an NSR cut-off of US$60/t. The Tin Zone is based on mining a total of 4.32 million tonnes grading 0.92% Sn over a 15-year LOM using an NSR cut-off of US$80. The mill feed will be trucked to the surface via multiple ramp systems connecting the three mine portals to the underground infrastructure and accessing production areas starting at the South and West areas of the Zinc Zone, the Silver Zone, and the high recovery area of the Tin Zone.

Mine Backfill
The zinc tailings mineralogy is favorable for the production of paste however the presence of a minor amount of kaolinite, and a relatively low content of pyrite and marcasite which contain sulphur, was observed.

Tinka has selected a paste plant site roughly 400 m north of the mill sites at Elevation 4,240 m. Tailings will be generated by both the zinc mill and tin mill, and then dewatered to a filter cake. During paste plant operations the filter cake will be trucked to a conventional dry paste plant. When the paste plant is not running the tailings will be trucked to the adjacent dry stack.

Paste will be delivered to the Zinc Zone through a network of surface reticulation system piping, boreholes, and an underground distribution system.

Comminution

Crushers and Mills

Summary:

Zinc, Lead and Silver Processing
Primary Crushing
ROM material will be hauled by dump trucks from the underground mine to the crushing area on surface where the mill feed material will be discharged into a ROM bin.

The bin will be installed with a static grizzly and a hydraulic rock breaker to fracture the oversize rocks. An apron feeder will recover material from the bin, feeding the vibrating grizzly where first coarse classification occurs. The oversize mill feed material will be sent to a primary jaw crusher, while both the crushed and undersize passing material will be transported by conveyor belts to the coarse stockpile. The belt conveyor will be equipped with an electromagnet to remove metallic objects that could damage the equipment downstream.

The coarse stockpile will act as surge protection to ensure the concentrator continues to operate while the mine or crushing plant are not producing. From the coarse stockpile, vibratory feeders will reclaim coarse mill feed material to feed into the grinding circuit.

Grinding and Classification
SAG mill discharge will be screened by a trommel. The coarse scat material will be placed by conveyors onto a scat stockpile, which will be periodically removed by front end loader to either the SAG feed, or else to waste storage. The trommel undersize will report to a pump box along with the tailings from the lead-silver flotation rougher flotation cells. At the pump box, a centrifugal pump will feed a hydrocyclone cluster which will classify the material so that it is suitable for zinc flotation.

The fine hydrocyclone overflow material will be transported by gravity to the zinc rougher conditioning stage prior to being sent to the dedicated zinc flotation circuit. The coarse hydrocyclone underflow material will report back to the ball mill for further grinding.

Tin Processing
The initial phase of the processing involves three stages of crushing to reduce the material to a size suitable for the subsequent grinding process. The primary jaw crusher will reduce the feed size, which is then further reduced in a secondary cone crusher and tertiary cone crusher. Between each stage of crushing, the material is screened of fines. The fine material product reports to the fine feed bin, and subsequently to the grinding mills.

Fine feed material undergoes a two-stage grinding process involving primary and secondary ball milling. This phase aims to achieve optimal liberation of the tin-bearing mineral phases. The finely ground material is then subject to hydrocyclone classification, segregating the fine and coarse fractions, with the fines proceeding to the concentration phase, and the coarse returning to the secondary ball mill.

Processing

• Gravity separation
• Crush & Screen plant
• Sulfuric acid (reagent)
• Vacuum filtration
• Acid leach
• Shaker table
• Jameson Cell Flotation
• Flotation
• Dewatering
• Filter press

Summary:

The zinc, lead, and silver processing involves conventional crushing, grinding, flotation, and dewatering to produce zinc and lead-silver concentrates, with tailings used for backfill or disposed of in a tailings storage facility. The tin processing parallels this approach, focusing on maximised recovery through comminution, concentration, and leaching.

Zinc, Lead and Silver Processing
A 5,500 t/d throughput rate was selected as the basis for the 2024 PEA.

Processing of the zinc mineralization will be through a conventional primary crushing, semi-autogenous grinding (“SAG”), secondary ball mill grinding, lead and silver flotation, zinc flotation, concentrate thickening and filtration. The concentrator plant will produce two concentrates: a zinc concentrate and a lead–silver concentrate.

The zinc processing plant will consist of the following unit operations:
• Primary jaw crushing;
• Crushed ROM handling;
• SAG milling;
• Ball mill secondary grinding in a closed circuit with hydrocyclone classification;
• Lead circuit, including rougher flotation, cleaner flotation;
• Zinc circuit, including rougher flotation, regrind, cleaner flotation;
• Concentrate dewatering (zinc and lead–silver concentrates);
• Flotation tailings thickening, filtration and stacking onto a filtered TSF;
• Tailings backfill plant;
• Fresh and reclaim water supply; and
• Reagent preparation and distribution.

Lead–Silver Flotation
The ball mill discharge will feed the lead–silver flotation Jameson flotation cells. This circuit will comprise of rougher and cleaner flotation stages.

Zinc Flotation
The zinc flotation circuit will consist of rougher, regrind, cleaner and cleaner–scavenger stages. Jameson pneumatic flotation cells will be used in the zinc flotation circuit to produce a zinc concentrate. Jameson-type cells were selected because of the capacity for fine air bubble generation, intense mixing, high bubble loading, and efficient froth washing which promote higher grade concentrates when compared to conventional mechanical cells.

Zinc Concentrate Dewatering
The zinc concentrate high-rate thickener underflow will be pumped to a press filter to produce a final concentrate cake. Concentrate cake will be trucked to either a local refinery for sale, or to a port of export for sale.

Lead–Silver Concentrate Dewatering
The lead flotation concentrate will be pumped to a concentrate tank, and then pumped to a vacuum disc filter. Final concentrate cake will be transported by truck to a port for sale.

Tailings Dewatering Process and Disposal
A conventional high-rate thickener is proposed for tailings thickening. Tailings will be dewatered and the underflow will report to a filter press where it will be further dewatered to produce a filter cake. Part of the filtered tailings will be stored on the surface in compacted piles in a dedicated filtered TSF. The remainder will report to a mine backfill plant where it will be mixed with cement and transported underground to be deposited in mine voids for permanent storage.

Tin Processing
A 850 t/d throughput rate was selected as the basis for the PEA.

The tin processing plant will consist of the following unit operations:
• Primary jaw crushing;
• Secondary and tertiary cone crushing;
• Ball mill primary grinding in an open circuit;
• Ball mill secondary grinding in a closed circuit with hydrocyclone classification;
• Sulfide flotation;
• Gravimetric concentration;
• Ball mill regrinding in a closed circuit with hydrocyclone classification;
• Tin flotation;
• Leaching;
• Tin concentrate dewatering;
• Flotation tailings thickening and filtration;
• Fresh and reclaim water supply; and
• Reagent preparation and distribution.

Beneficiation
The beneficiation process begins with sulfide flotation, where pyrite and pyrrhotite are selectively separated and directed to tailings, achieving the recovery of non-sulfide tin mineralization. The resultant non-sulfide stream is then processed through a series of centrifugal bowl gravity concentrators. These concentrators are designed to capture the denser tin particles, while lighter material is removed as tailings.

The concentrate from the gravity concentrators undergoes sulfide scalping flotation to remove residual sulfides, enhancing the tin concentrate's purity. Middlings from this process are reground and recycled back to the gravity concentrators, ensuring maximal tin recovery. Tailings from the gravity circuit, prior to tin flotation, are subjected to scavenging sulfide flotation to eliminate residual sulfides, then, tailings from this flotation are subjected to tin flotation to recover any remaining tin values, minimizing losses.

Leaching
To further enhance concentrate quality, the combined product from gravity concentration and scavenging flotation undergoes a sulfuric acid leaching process. This step is useful for removing siderite (iron carbonates), thus improving the grade of the tin concentrate.

Following leaching, the slurry is thickened. The thickened slurry is then filtered to produce a tin concentrate, which is dispatched by truck for sale to third party refineries.

Tin Concentrate Dewatering
The tin concentrate conventional thickener underflow will be pumped to a press filter to produce a final concentrate cake. Concentrate cake will be trucked to a port of export for sale.

Tailings Dewatering Process and Disposal
A conventional thickener is proposed for tailings thickening. Tailings will be dewatered and the underflow will report to a filter press where it will be further dewatered to produce a filter cake.

Water Supply

Summary:

The projected process water requirements, the zinc plant will require around 48 m³/hr as make-up water, and the tin plant require 8 m³/hr as make-up water. This make up water is expected to be supplied by a combination of:
• Mine dewatering water;
• Site surface runoff capture;
• Raw water wells.

Mine water is planned to be recycled as much as possible. Runoff water from the temporary waste rock piles adjacent to the portals and recycled water from the filtered TSF are to be used for plant operations. The water management system will include diversion channels for non-contact surface water runoff around the temporary waste rock piles and the filtered TSF, as well as including ditches in the perimeter of infrastructure platforms and roads and pipes or culvert concrete boxes for stream crossings. This non-contact water will be discharged to creeks located downstream of the planned operations.

The zinc plant will require around 48 m³/hr as make-up water, and the tin plant require 8 m³/hr as make-up water. Potential make-water sources include water ponds to be constructed within the site layout. Fresh water will be required to complement make-up water for the plant. The Project will require a water license for use of fresh water and may also require an authorization to discharge liquid effluents.

Commodity Production

Operational metrics

Personnel

Job Title	Name	Email	Profile	Ref. Date
Consultant - Mining, Infrastructure & Costs	Christopher Bray			Feb 28, 2024
Consultant - Mining, Infrastructure & Costs	Donald Hickson			Feb 28, 2024
Consultant - Recovery Methods & Costs	Adam Johnston			Feb 28, 2024
President and CEO	Graham Carman	gcarman@tinkaresources.com		Mar 1, 2024
Project Manager	Jorge Edgardo Gamarra Urrunaga			May 31, 2024