This report details the process design for two concentrator plants,an expansion of the existing Nueva Recuperada plant to 1,500 t/d and a new 1,500 t/d Tangana plant,based on historical operating data, existing plant experience, and design assumptions.
Report context
This Preliminary Economic Assessment (PEA) for the Tangana and Plata Mining Projects, Nueva Recuperada Project, describes recovery methods for two mineral processing plants. The existing Nueva Recuperada concentrator, located 22 km north of the proposed Tangana plant site, currently operates at a nominal capacity of 600 t/d treating copper, lead, zinc, and silver minerals from the Tangana, Maria Luz, Positivas, San Antonio, and Pucapunta mines. The report presents a proposed expansion of the Nueva Recuperada plant to 1,500 t/d and a new 1,500 t/d Tangana concentrator, using process design criteria established from operational experience, historical production data from 1963–2013, and experience with similar polymetallic operations.
Processing route
Nueva Recuperada plant,proposed expansion to 1,500 t/d
The proposed processing route would begin with primary crushing using a TRIO 20" x 36" jaw crusher preceded by a vibrating grizzly. Crushed material would report to a fines hopper before feeding a new 16'x6' SAG mill operating as primary grinding equipment, reducing material from F80 3/4" to P80 2.0 mm. A trommel at the SAG mill discharge would separate material by size, with discharge feeding a battery of cyclones for classification. The secondary grinding circuit would comprise four ball mills: two existing mills (6'x6' and 6'x4.5') and two new mills (6'x12' and 6'x6'). Cyclone underflow would return to the secondary grinding circuit, while cyclone overflow at P80 150 µm would report to flotation.
The flotation circuit would be divided into three sequential stages: bulk flotation, selective flotation, and zinc flotation. The bulk flotation circuit would include two rougher stages, two scavenger stages, and a cleaning circuit with two stages in parallel (cleaner IA and cleaner IB). The bulk concentrate would be thickened and filtered for sale. Tailings from the second scavenger stage would be conditioned prior to zinc flotation. The zinc flotation circuit would operate with two sequential rougher stages, two cleaning stages, and three consecutive scavenger stages. The final zinc concentrate from the second cleaning stage would be thickened and filtered.
Concentrate thickening and filtration would leverage existing infrastructure, complemented by additional equipment. The tailings treatment system would maintain the current configuration, requiring only operational adjustments and improved pumping capacity. The plant would produce two concentrates: a bulk Cu-Pb-Ag concentrate and a zinc concentrate.
Tangana plant,proposed new 1,500 t/d concentrator
The proposed Tangana processing route would begin with primary jaw crushing followed by secondary screening and cone crushing. Material would be reclaimed from a RoM bin using a vibrating grizzly feeder, passing to a trommel where process water would be added to remove clays. Fine material and water would flow directly to the mill pump box. Coarse material would be fed to the primary crusher, with crushed material reporting to a vibrating screen. Screen oversize would feed the secondary crusher, with product reporting to a fine feed bin.
Primary grinding would be performed by a rod mill reducing material from 45 mm to 2.2 mm, followed by ball mill secondary grinding in closed circuit with hydrocyclone classification to achieve P80 74 µm. A gravity bowl concentrator would scalp coarse gold from a fraction of the cyclone underflow, with concentrate cleaned on a shaking table to commercial quality. Gravity tailings would be directed to flotation.
The bulk flotation circuit would include rougher, cleaner, and scavenger stages to recover copper, lead, and silver. The zinc flotation circuit would involve activation with copper sulfate, conditioning, rougher flotation, regrind to P80 54 µm, cleaner flotation, and scavenger flotation to maximize sphalerite recovery. Flotation circuit control would be aided by an inline analyzer.
Concentrate dewatering would use high-rate thickening followed by filter pressing to produce filter cake at 6% moisture for both bulk and zinc concentrates. Tailings would be thickened to approximately 57% solids, then filtered to 12% moisture for disposal in a subaerial tailings storage facility or as underground mine backfill. Process water would be recycled. The plant would produce three concentrates: a lead-silver concentrate (anticipated 55% Pb, 51–99 oz/t Ag), a zinc concentrate (anticipated 52% Zn), and a coarse gold concentrate for third-party refining.
Key reported parameters
| Parameter | Nueva Recuperada (proposed expansion) | Tangana (proposed new plant) | Basis |
|---|---|---|---|
| Nominal processing rate | 1,500 t/d | 1,500 t/d | Proposed design |
| Current operating rate | 600 t/d | , | Historical operating data |
| Annual ROM production | 433,721 t/year | 499,950 t/year | Customer estimate |
| ROM D80 | 140 mm | 900 mm | Typical (Nuva Recuperada); typical (Tangana) |
| ROM D100 | 300 mm | 1,000 mm | Typical |
| SG ROM | 2.74 g/cm³ | 2.74 g/cm³ | Existing plant data |
| Abrasion index (A) | 0.3 g | 0.3 g | Estimated |
| Clay in ROM | <5% | <5% | Customer estimate |
| Wi rod mill | 16 kWh/t | 22 kWh/t | Typical value range (Nuva Recuperada); estimation from existing plant (Tangana) |
| Wi ball mill | 14–18 kWh/t | 17 kWh/t | Typical value range (Nuva Recuperada); estimation from existing plant (Tangana) |
| Wi crushing | 18 kWh/t | 18 kWh/t | Typical value range (Nuva Recuperada); estimation from existing plant (Tangana) |
| Feed moisture | 3% | , | Existing plant data |
| Bulk density Pb concentrate | 2.9 t/m³ | 2.9 t/m³ | Estimate of existing plant department |
| Bulk density Zn concentrate | 2.7 t/m³ | 2.7 t/m³ | Estimate of existing plant department |
| Bulk density filtered tailings | 2.3 t/m³ | 2.3 t/m³ | Estimated |
| Tailings moisture | 12% | 12% | Typical |
| Pb concentrate moisture | 6% | 6% | Typical |
| Zn concentrate moisture | 6% | 6% | Typical |
| Operating hours per shift | 12 h | 12 h | Existing plant data |
| Operating days per year | 365 days | 1 day | Existing plant data |
| Crushing area availability | 85% | 85% | Estimated |
| Availability rest of plant | 90% | 90% | Estimated |
| Installed power | 2,770 kW | 3,015 kW | Proposed design |
| Annual power consumption | 13,220,936 kWh | 14,239,479 kWh | Proposed design calculation |
| Head grade Ag (Tangana feed) | , | 2.37 oz/t | Existing plant data |
| Head grade Pb (Tangana feed) | , | 1.47% | Existing plant data |
| Head grade Zn (Tangana feed) | , | 1.48% | Existing plant data |
| Ag grade in Pb concentrate (Tangana) | , | 53 oz/t | Existing plant data |
Project website: https://www.silverxmining.com/projects/nueva-recuperada-silver-district-2/
Technical qualifications
This Preliminary Economic Assessment includes process design criteria that are largely assumed based on operational experience at the existing Nueva Recuperada concentrator, historical production data from 1963–2013, and experience with similar polymetallic operations. The Tangana plant design is fit-for-purpose with a project life of about 15 years and includes no consideration or allowance for future expansion. For the Tangana plant, much of the process design criteria have been assumed, and the report notes that only high-level evaluations have been made for water sourcing, recommending that quality testing of different sources be performed in future studies to reduce processing risk in terms of metal recovery and concentrate grades. The report does not provide testwork results for the proposed flowsheets, nor does it present detailed flotation performance data, metallurgical balances, or economic parameters.
Source: NI 43-101 Preliminary Economic Assessment for the Tangana Mining Project and Plata Mining Project, Nueva Recuperada Project, Recovery Methods section.
