The proposed processing route is a conventional zinc and lead–silver flotation circuit, based on metallurgical testwork that demonstrated amenability to froth flotation for zinc and lead–silver mineralization.
Report context
This technical report describes the Ayawilca Polymetallic Project as defined in the 2021 technical report. The project is a greenfields site located in a remote mountainous river valley area, 310 km by road north of Lima. The processing plant design is based on a lean, fit-for-purpose standard to cover the required duty for a projected 14-year mine life. The design accommodates nominal operation with a small degree of capacity flexibility for upsets and variability but has no consideration or allowance for any expansion. Site development earthworks are a major project consideration due to topography and potential geological hazards.
Processing route
Basis of circuit selection
The selection of a conventional zinc and lead–silver flotation processing circuit for Ayawilca was based on metallurgical testwork including locked cycle tests for zinc and open cycle tests for lead–silver. Metallurgical testwork showed that the Zinc Zone mineralized material is amenable to froth flotation, achieving commercial zinc concentrate grades and recoveries.
Proposed processing plant
Processing of the zinc–lead–silver mineralization will be through a conventional flowsheet comprising 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 processing plant will consist of the following unit operations:
- Primary jaw crushing
- Crushed ore 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 filtered tailings storage facility (TSF)
- Tailings backfill plant
- Fresh and reclaim water supply
- Reagent preparation and distribution
Lead–silver flotation
A dedicated lead–silver flotation circuit (rougher–cleaner cells) was included to maximize net revenue from silver production. To recover the lead–silver mineralization, a flotation stage comprising pneumatic cells in a rougher–cleaner–scavenger arrangement is proposed.
Tailings and water management
A portion of the tailings (39%) will be mixed with cement and used as structural mine backfill material in the underground operations, while the remainder (61%) will be thickened and filtered, then disposed of in a filtered TSF. Process water will be recycled as much as possible to minimize water usage.
Key reported parameters
| Parameter | Detail | Basis |
|---|---|---|
| Mine life | 14 years projected | Design basis |
| Concentrates produced | Zinc concentrate; lead–silver concentrate | Proposed design |
| Tailings backfill proportion | 39% to underground backfill | Proposed design |
| Tailings to filtered TSF | 61% | Proposed design |
| Lead–silver flotation cells | Pneumatic cells, rougher–cleaner–scavenger arrangement | Proposed design |
| Zinc flotation testwork | Locked cycle tests | Testwork |
| Lead–silver flotation testwork | Open cycle tests | Testwork |
| Zinc Zone flotation amenability | Froth flotation, commercial grades and recoveries | Testwork |
Project website: https://tinkaresources.com/home/
Technical qualifications
The design has no consideration or allowance for any expansion. The report states that the processing plant design is based on a lean, fit-for-purpose standard. The project is a greenfields site. Site development earthworks will be a major project consideration due to site limitations imposed by topography and potential geological hazards. Access improvements include a proposed new road to the site from the town of Chinche, approximately 10 km west of Yanahuanca.
*Source: Ayawilca Polymetallic Project , 2021 Technical Report, sections 1.14 Recovery Methods and 1.15 Infrastructure.*
