This revised preliminary economic assessment describes a 15 Mtpa copper-gold concentrator design with associated magnetite by-product recovery, based on conventional processing units.
Report context
The Taysan Copper-Gold Project Revised PEA (2012) was prepared in February 2012 as an order-of-magnitude scoping study update, reducing plant throughput from 30 Mtpa to 15 Mtpa as requested by CZH. The study was intended to provide an indication of capital expenditure, operating expenditure, and potential internal rate of return improvements to guide the project toward prefeasibility and bankable feasibility studies.
Processing route
Primary crushing and ore storage
The concentrator design is based on a maximum copper head grade of 0.60% and a maximum gold head grade of 0.20 g/t, processing 15 Mtpa using a single processing line. The primary crushing circuit, designed for 75% availability and 90% utilisation (67.5% operating utilisation), comprises a 62-inch by 75-inch gyratory crusher delivering 2,537 t/h to meet mill throughput. Coarse ore is stored in a stockpile with 12 hours live capacity (22,500 tonnes) and dozable capacity of 100,000 tonnes, equivalent to two days operation. Reclaim uses three apron feeders, each capable of delivering up to 1,000 t/h to the milling circuit.
Grinding and classification
A SAG-ball (SAB) grinding circuit is designed with 91.3% overall availability, processing nominally 1,875 t/h. The circuit comprises a single 16 MW SAG mill (38 ft by 20 ft) and a single 16 MW ball mill (26 ft by 44 ft) operating in closed circuit. Allowance has been made for possible future installation of a pebble crusher circuit if required.
Flotation and copper concentrate handling
The flotation circuit consists of rougher flotation with two stages of cleaning. Rougher flotation uses six 300 cubic metre tank-type flotation cells. Rougher concentrate is cycloned prior to regrind in an M10000 ISAMill to achieve a 60 micrometre product. The cleaner flotation circuit comprises four 70 cubic metre cleaner cells, three 70 cubic metre cleaner scavenger tank-type flotation cells, and two 3-metre diameter re-cleaner columns.
Re-cleaner flotation concentrate is thickened in a 15-metre diameter Outotec thickener, with overflow recycled to the process circuit. Thickened concentrate is filtered on a vertical plate and frame filter, then stored in a bulk copper concentrate storage shed. A front-end loader loads concentrate trucks for transport to port.
Magnetite recovery
Magnetite is recovered as a by-product from copper flotation tailings streams. The recovery circuit comprises nine wet low-intensity magnetic separator drums (WLIMS) in the rougher circuit. Non-magnetic tails from rougher magnetic separation are pumped to the final tailings thickener. Rougher magnetite concentrate is ground in a closed-circuit 1.6 MW ball mill. The cleaner circuit uses two triple-drum WLIMS separators, with tails reporting to final process plant tailings. Cleaner magnetic separator concentrate is de-magnetised and thickened in a 20-metre diameter Outotec thickener, with overflow recycled and underflow dewatered on a vertical plate and frame filter. Filtered magnetite concentrate is stockpiled in a bulk magnetite concentrate storage shed.
Tailings and process control
Tailings from the rougher and cleaner scavenger flotation circuits are flocculated and thickened in a 55-metre diameter thickener. Underflow is discharged to the tailings storage facility, with overflow returned to the process plant. Make-up process water is collected from the tailings storage facility along with additional raw water.
The control philosophy uses a typical system for contemporary mineral processing operations, with field instrumentation providing inputs to the Process Control System via fibre optic data network. Control modules located in Motor Control Centres perform instrument monitoring, loop control, drive control, process interlocking, and proportional-integral-derivative control.
Key reported parameters
| Parameter | Basis | Unit | Quantity |
|---|---|---|---|
| Annual Capacity | Design | t/a | 15,000,000 |
| Concentrator Operating Time | Design | h/a | 8,000 |
| Concentrator Throughput Rate | Design | t/h | 2,537 |
| Ore Head Grade – Copper | Design | % | 0.6 |
| Ore Head Grade – Gold | Design | g/t | 0.2 |
| Ore Head Grade – Copper | LOM | % | 0.3 |
| Ore Head Grade – Gold | LOM | g/t | 0.1 |
| Copper Concentrate Production | Design | t/a | 300,000 |
| Contained Copper Metal | Design | t/a | 81,000 |
| Contained Gold Metal | Design | oz | 48,226 |
| Copper Concentrate Production | LOM | t/a | 150,000 |
| Contained Copper Metal | LOM | t/a | 40,500 |
| Contained Gold Metal | LOM | oz | 24,113 |
| Magnetite Production | LOM | t/a | 364,000 |
| Copper Recovery | Design | % | 90 |
| Gold Recovery | Design | % | 60 |
| Silver Recovery | Design | % | 57 |
| Magnetite Recovery | Design | % | 52 |
| Primary Crusher – type | Design | 62" x 75" gyratory | |
| Primary Crusher Circuit Throughput | Design | t/h | 2,537 |
| SAG Mill – power | Design | MW | 16 |
| SAG Mill – dimensions | Design | ft | 38 x 20 |
| Ball Mill – power | Design | MW | 16 |
| Ball Mill – dimensions | Design | ft | 26 x 44 |
| Regrind Mill – type | Design | M10000 ISAMill | |
| Regrind Product Size | Design | µm | 60 |
| Total Installed Load | Design | kW | 78,846 |
| Total Average Running Load | Design | kW | 52,708 |
| Annual Energy Consumption | Estimate | MWh | 421,124 |
| Power Cost | Estimate | US$/kWh | 0.128 |
Project website: https://www.northernminer.com/news/hounded-by-shortsellers-chase-offers-legal-opinions-to-dispel/1000187477/
Project website: https://www.mining.com/web/crazy-horse-resources-inc-completion-of-pre-feasibility-study-on-taysan-copper-gold-project/
Technical qualifications
Specific data for the Taysan process design was sourced from Metcon and Ammtec laboratory test work, Chase Minerals Corporation Optimet Test Work Report 95034 (December 1995), the AMEC Minproc in-house database, and preliminary vendor and catalogue data. The scoping study update is described as an order-of-magnitude exercise. The SAG mill and ball mill power values are design parameters. The flotation circuit is designed on the basis of 1,875 t/h throughput and nominal feed grade comprising 0.30% Cu with 90% overall copper recovery to a 27% copper concentrate, representing a different basis than the maximum head grade used for overall concentrator design.
Source: Taysan Copper Gold Project – Revised PEA- 15Mtpa Mine (Increased Magnetite), February 2012. Sections 17 Recovery Methods, 17.1 Process Description, 17.2 Process and Equipment Selection.
