SRK's November 2012 preliminary economic assessment for the Ak-Sug copper-molybdenum project in Russia's Tyva Republic targets 90% copper recovery into a 27% copper concentrate and a molybdenum concentrate of at least 50% Mo.
The Preliminary Economic Assessment, Ak-Sug Copper-Molybdenum Project, Todja Kozhuun District, Tyva Republic, Russian Federation, was prepared by SRK Consulting (Russia) Ltd. for Intergeo MMC Ltd and LLC Golevskaya GRK with an effective date of November 8, 2012. SNC developed the flowsheet and the engineered tailings dam design, drawing on Gipronikel's 2009 testwork, and SRK designed the waste-dump tailings option. The plant is a conventional copper-molybdenum flowsheet for 24 Mt/a. Grinding is followed by bulk flotation of a copper-molybdenum sulphide concentrate, then differential flotation to separate the molybdenum. Gold and silver report to the copper concentrate and rhenium to the molybdenum concentrate.
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Report effective date | November 8, 2012 | Not applicable | SRK for Intergeo MMC Ltd and LLC Golevskaya GRK |
| Throughput | 24 | Mt/a | 65,750 t/d; 2,740 t/h |
| Crushed product | 80% passing 150 | mm | Overland conveyor to the stockpile |
| Grind | 80% passing 140 | µm | One SAG mill, pebble crusher and two ball mills |
| Regrind | 80% passing 35 | µm | Two regrind mills |
| Bulk cleaning | Three stages plus cleaner scavenger | Not applicable | Not applicable |
| Molybdenum circuit | Rougher-scavenger and three cleaners | Not applicable | Scavenger tails are the copper concentrate |
| Copper target | 90% recovery, 27% Cu concentrate | Not applicable | Testwork still to confirm |
| Molybdenum target | 60% recovery, at least 50% Mo | Not applicable | Ideally below 1% Cu |
| Tailings facility | Valley fill about 8.8 km from the plant | Not applicable | Site B1 behind a waste dump |
| Concentrate haulage | About 240 km to the railhead | Not applicable | 24 to 30 truck round trips a day for copper |
Overview
Ore is crushed and conveyed to a coarse stockpile near the concentrator, then ground in a single line before two parallel banks of bulk rougher flotation. The bulk rougher concentrate and cleaner middlings are reground together to improve liberation, grade and recovery. The cleaned bulk concentrate goes to molybdenum flotation, which produces a molybdenum concentrate, while the molybdenum scavenger tails form the final copper concentrate. Both concentrates are dewatered in pressure filters. Copper concentrate is shipped in bulk, and molybdenum concentrate is dried and bagged. The report notes that further testwork is needed to show whether the recovery and grade targets can be met.
Key Process Stages
Crushing and conveying. Primary crushing produces coarse mill feed at 80% passing 150 mm, carried by overland conveyor to the coarse ore stockpile.
Grinding. One grinding line, a SAG mill with a cone crusher for pebble screen oversize and two ball mills in closed circuit with cyclones, grinds to 80% passing 140 µm.
Bulk flotation and regrind. Cyclone overflow feeds two parallel banks of bulk roughers. The rougher concentrate and cleaner middlings are reground in two mills to 80% passing 35 µm, then cleaned in three stages. Second and third cleaner tails return to regrind, first cleaner tails go to cleaner scavengers, and cleaner scavenger tails return to the roughers. The third cleaner concentrate is thickened and sent to the molybdenum circuit.
Molybdenum flotation. One bank of rougher-scavenger cells and three cleaner stages, each returning its tails to the previous stage, produce the final molybdenum concentrate. The first cleaner concentrate is thickened before the second cleaner.
Concentrate handling. Copper concentrate is to be trucked about 240 km to the railhead in 26.5 t dump trucks, a roughly nine-hour round trip, with 24 to 30 trips a day, then railed in 40 t cars. Molybdenum concentrate goes in bulk bags on 20 t flat-deck trucks, six round trips a week.
Tailings. Unthickened bulk rougher tails are pumped to a valley-fill tailings facility about 8.8 km away. Reclaim water returns by barge-mounted vertical turbine pumps, and more water comes from a clean water dam 4.5 km north.
Additional Interesting Data and Summary
Eight possible tailings sites were assessed in the cirque valleys draining into the Ak-Sug valley, sized for 315 Mm³ of tailings from 378 Mt of ore at a settled density of 1.4 t/m³. Site B1, behind a waste dump near the pit, was preferred. Because the area is moderately to highly seismic, gets about 600 mm of precipitation a year and has 243 days below 0°C, the design uses free-draining rockfill with flat slopes. Tailings will be spigotted from the dam crest in warmer months and discharged under water in freezing months to avoid trapping ice in the deposit.
In summary, the 2012 Ak-Sug PEA is a large-scale, conventional porphyry copper-molybdenum concentrator at 24 Mt/a in a remote, cold, seismic setting. Its targets of 90% copper and 60% molybdenum recovery remain to be confirmed by testwork.
Key Processes
- Primary crushing and overland conveying
- SAG milling with pebble crushing and two ball mills to 80% passing 140 µm
- Bulk rougher flotation in two banks
- Regrind of rougher concentrate and middlings to 35 µm
- Three-stage bulk cleaning and cleaner scavenging
- Molybdenum rougher-scavenger and three-stage cleaner flotation
- Pressure filtration, molybdenum drying and bagging
- Valley-fill tailings with reclaim water
Source: Preliminary Economic Assessment, Ak-Sug Copper-Molybdenum Project, Todja Kozhuun District, Tyva Republic, Russian Federation, SRK Consulting (Russia) Ltd., effective date November 8, 2012.
Earlier report summaries
Earlier versions of this profile, based on older technical reports, are retained below for source traceability. Dates and figures reflect each report’s own effective date and are superseded by the current information above.
Ak-Sug — 2011 Technical Report (Recovery Methods)
This section describes the proposed processing flowsheet, plant design, and tailings management for the Ak-Sug copper-molybdenum project as outlined in the 2012 Preliminary Economic Assessment.
Report context
The Recovery Methods section forms part of a National Instrument 43-101 Preliminary Economic Assessment technical report for the Ak-Sug copper-molybdenum project, located in the Todja Kozhuun District, Tyva Republic, Russian Federation. The report was prepared for Intergeo MMC Ltd and LLC Golevskaya GRK, with an effective date of 8 November 2012. The processing and recovery information presented herein is based on the proposed design for the project; no historical operating data or testwork results are reported in this section of the technical report.
Processing route
Overview
The proposed processing facility is designed to treat ore from the Ak-Sug deposit through a conventional copper-molybdenum sulphide flotation flowsheet. The plant design is based on the mineral processing and metallurgical testing work detailed in Section 13 of the technical report, although the Recovery Methods section does not itself present specific testwork results. The processing route is intended to produce separate copper and molybdenum concentrates.
Processing Flowsheet
The proposed processing flowsheet includes primary crushing, semi-autogenous grinding (SAG) and ball milling, followed by bulk copper-molybdenum flotation. The bulk concentrate is then subjected to molybdenum separation using conventional regrinding and differential flotation to produce a molybdenum concentrate and a copper concentrate. The flowsheet design incorporates standard reagents including collectors, frothers, and modifiers typical for copper-molybdenum porphyry ore treatment. Thickening and filtration stages are included for concentrate dewatering and tailings management.
Processing Plant Description
The processing plant is designed for a throughput capacity that supports the proposed mining rate. The plant includes the following major process areas:
- Primary crushing station with gyratory crusher
- Coarse ore stockpile with reclaim system
- SAG mill and ball mill grinding circuit with cyclones
- Bulk flotation circuit comprising rougher, scavenger, and cleaner stages
- Molybdenum separation circuit with regrind mills and differential flotation cells
- Concentrate thickening and filtration for both copper and molybdenum products
- Reagent mixing and distribution systems
- Plant control system for process automation
The plant layout is configured to accommodate the site topography and to facilitate efficient material handling from the mine to the crusher and from the process plant to the tailings storage facility. All process equipment is designed for year-round operation under the local climatic conditions.
Tailings
Design basis
The tailings management facility (TMF) design basis includes the storage of flotation tailings from the processing plant. The design incorporates geotechnical and hydrological considerations appropriate for the site location. The TMF is designed to contain the total tailings volume over the life of the mine, with provision for staged construction as required by the production schedule.
Site selection
The tailings storage facility site was selected based on topographic, geotechnical, hydrological, and environmental criteria. The selected location is within the project area and provides adequate storage capacity with suitable foundation conditions. The site selection considered proximity to the processing plant to minimise tailings transport distance and to take advantage of natural containment features.
TMF water management
Water management for the tailings storage facility includes a system for reclaiming process water from the tailings pond for reuse in the processing plant. The design incorporates a decant system and return water pipeline to the plant. The water management system is designed to maintain a water balance that meets process water requirements while managing environmental considerations including seepage control and stormwater management.
Waste dump tailings facility
The tailings facility is designed as a conventional impoundment with embankment construction using waste rock from the open pit where suitable materials are available. The facility includes underdrainage systems, seepage collection, and monitoring provisions. The design incorporates geotechnical stability analyses for both static and seismic loading conditions.
Fresh Water Pond
A fresh water pond is included in the project infrastructure to supply make-up water to the processing plant. The pond is sized to provide adequate water storage for process operations, taking into account seasonal variations in water availability and the water balance of the processing and tailings system.
Processing Plant Operations and Management
The processing plant is designed to operate on a continuous basis with scheduled maintenance shutdowns. The operations and management plan includes staffing levels for process operations, maintenance, metallurgical control, and laboratory services. The plant control system is designed to monitor and adjust process parameters to maintain throughput and product quality targets.
Key reported parameters
| Parameter | Unit | Value | Basis |
|---|---|---|---|
| Processing route | , | Conventional copper-molybdenum sulphide flotation | Proposed design |
| Primary crushing | , | Gyratory crusher | Proposed design |
| Grinding circuit | , | SAG mill and ball mill | Proposed design |
| Flotation circuit | , | Bulk flotation with molybdenum separation | Proposed design |
| Concentrate products | , | Copper concentrate, molybdenum concentrate | Proposed design |
| Tailings facility type | , | Conventional impoundment with waste rock embankment | Proposed design |
| Water management | , | Reclaim water system with fresh water pond | Proposed design |
Project website: https://www.sciencedirect.com/science/article/abs/pii/S0375674215001120
Project website: https://resourceworld.com/russian-mining-company-intergeo-plans-to-accelerate-development-of-ak-sug-copper-project/
Technical qualifications
The Recovery Methods section of this technical report presents a conceptual process design developed for the Preliminary Economic Assessment. No specific testwork results, historical operating data, or metallurgical performance data are reported in this section. The process flowsheet and plant design are based on industry standard practices for copper-molybdenum porphyry deposits and on the mineral processing and metallurgical testing work referenced in Section 13 of the report. The information is presented at a PEA level of accuracy and should not be considered as final engineering design. Capital and operating cost estimates for the processing plant are presented elsewhere in the report.
Source: Preliminary Economic Assessment, Ak-Sug Copper-Molybdenum project, National Instrument 43-101 Technical Report, effective date 8 November 2012, Section 17 Recovery Methods.
