Rio2 Limited's Condestable Mine in Peru operates a conventional crushing, grinding, and flotation circuit that produces filtered copper concentrate for sale on the open market.
The Condestable Mine is an operating underground copper mine located in the Lima Department of Peru. The project is owned by Rio2 Limited, with the technical report prepared by SLR Consulting (Canada) Ltd. The mine operates through CMC, with ore processed in a flotation concentrator that was expanded from 7,000 tpd to 8,400 tpd capacity. The effective date of the technical report is May 31, 2026, with the signature date of July 22, 2026.
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Concentrator capacity | 8,400 | tpd | Expanded from 7,000 tpd |
| Primary crusher product size | 200 | mm | Nominal |
| Secondary crusher product size | 70 | mm | Nominal |
| Tertiary crusher product size | 35 | mm | Approximate |
| Quaternary crusher product size | 3.5 | mm | Nominal |
| Fine ore storage capacity | 6,500 | t | Six bins |
| Flotation feed size | 80% passing 200 | µm | Design |
| Grinding circuit solids | 32 | % | Approximate |
| Concentrate final moisture | 9.5 | % | Approximate |
| Tailings underflow density | 45 | % solids | Nominal |
| Concentrate thickener diameter | 7.62 | m | Two units |
| Tailings thickener diameter | 25 | m | Two units |
Overview
The recovery process at Condestable uses a conventional four stage crushing, grinding, and flotation circuit. The concentrator sits on a steep hillside above the administration offices and warehouse facilities. Holland & Holland Consultants assisted CMC with modifications to the concentrator design that expanded capacity from 7,000 tpd to 8,400 tpd. The Expansion Project included equipment modifications in crushing, milling, flotation, tailings pumping, and tailings thickening.
Ore from the Condestable and Raúl underground mines travels approximately three kilometres by truck to the concentrator plant. The major process components are crushing, grinding, flotation, dewatering, and tailings disposal.
Key Process Stages
Crushing
Ore from the underground mines is transferred to one of two primary jaw crushers. Material discharges from the primary crushers at a nominal 200 mm size and is placed in one of two coarse ore stockpiles. Belt feeders recover the ore from stockpiles and transfer it to a secondary HP500 standard cone crusher that reduces the material to a nominal 70 mm size. Secondary crusher products go to screens, with oversize reporting to the tertiary crusher and undersize directed to the quaternary crusher screens.
The tertiary crusher was originally an HP400 standard cone crusher that reduced ore to approximately 35 mm before the quaternary crushing system. The Expansion Project replaced this unit with an HP500 standard cone crusher. Tertiary crusher product feeds the screening plant, where ore separates into fine ore at a nominal 3.5 mm size. Oversize material passes to the quaternary crusher bins. Four HP400 short head crushers reduce oversize material to a nominal 3.5 mm size to feed the milling circuit. These crushers operate in closed circuit with four 2.44 m by 6.10 m screens that control the size of the fine ore.
Grinding
Fine ore from the crushing plant stores in six bins with a total capacity of 6,500 t. Each bin is an individual feed source for one of six primary grinding ball mills. Number 4 mill operates on occasion as a primary mill, with Number 2 and Number 3 mills as secondary ball mills.
A weightometer on each mill feed conveyor controls discharge from the bins. The primary grinding mills operate with a combination of cyclones and Derrick screens to generate a flotation feed product of 80% passing 200 µm. The mills in use include a Number 1 R/G Kurimoto 2.13 m by 2.44 m unit with a 255 HP motor, a Number 2 Kurimoto of the same dimensions with 255 HP, a Number 3 Comesa 2.44 m by 3.05 m unit with 422 HP, a Number 4 Allis Chalmers 2.74 m by 3.66 m mill with 500 HP, a Number 5 Allis Chalmers 3.66 m by 4.27 m unit with 1,000 HP, a Number 6 Nordberg 3.81 m by 4.72 m mill with 1,250 HP, a Number 7 Fuller 3.96 m by 5.18 m unit with 1,850 HP, a Number 8 Comesa 2.44 m by 3.05 m mill with 255 HP, and a Number 9 Metso 4.11 m by 8.53 m unit with 3,077 HP. Numbers 4, 5, 6, and 7 mills operate with Derrick screens to control the mill circuit product. Number 1 mill is a rougher regrind unit operating with 25.4 cm cyclones. All products combine to form the flotation feed at 80% passing 200 µm.
Number 8 ball mill installation for regrinding was completed in October 2017 to increase process flexibility when encountering harder ore or for additional regrind capacity. The mill operates either as a primary grinding mill or as a rougher concentrate regrind mill. The Expansion Project included the installation of Number 9 ball mill with a nest of eight hydrocyclones and two horizontal pumps. Minor modifications to the electrical supply system were required to accommodate the new mill. Replacement of the starter panel for Number 9 ball mill completed in July 2022. Number 6 mill operates in an open circuit with discharge delivered to the pump box of Number 9 ball mill, eliminating classification with a high-frequency sieve.
Flotation
Product from the grinding circuit contains approximately 32% solids and feeds the copper rougher-scavenger circuit. This circuit consists of 16 OK 38 cells, with each cell at 38 m³ in size, arranged as four banks of four cells. The first four cells operate as a high grade rougher, while the remainder operates as a three stage scavenger circuit. Concentrate from the first four-cell scavenger bank passes to the cleaner scavenger for upgrading before recycling to the cleaner feed. The final two scavenger banks produce a scavenger concentrate as feed to the regrind circuit, which recycles back to the flotation feed. The Expansion Project added a new bank of four OK 38 cells to operate as a fourth stage scavenger circuit.
The primary cleaner consists of two banks of three OK 8 type flotation cells. Primary cleaner concentrate passes to a two-cell OK 8 secondary cleaner, with secondary cleaner tailings passing directly to the primary cleaner feed. Primary cleaner scavenger concentrate recirculates back as primary cleaner flotation feed. Tailings from primary cleaner flotation pass to the regrind circuit if sufficient capacity is available, or the material passes directly to plant feed. An OK 20 cell was added to process the regrind overflow to reduce the recirculation of iron in the circuit.
Automatic samplers collect samples of the feed, concentrate, and tailings streams for analysis and metallurgical accounting. An Outotec Courier on-line analyzer provides on-stream analysis of copper, iron, and percent solids for plant operations control at three points: mill feed, concentrate, and final tailings.
Dewatering
Concentrate from the cleaner circuit passes to one of two 7.62 m diameter thickeners for thickening. Water from the thickener overflow is recycled. The underflow at 60% solids feeds two 2.44 m by 2.44 m Dorr Oliver drum filters and one Fima disc filter. The concentrate dewaters to a final moisture content of approximately 9.5%. No changes were required in concentrate filtration to accommodate the higher production in the Expansion Project.
Filter product discharges by gravity to a storage hopper, where the material loads onto trucks using a scraper. Covered trailers containing the concentrate are weighed on the plant weighbridge before shipment. The concentrate transports by truck to the port of Callao on a daily basis.
Tailings Disposal
Tailings from the rougher-scavenger bank pump to a 25 m diameter high rate thickener with an underflow density of a nominal 45% solids. The tailings slurry discharges by gravity into the tailings storage facility situated north of the plant. Hydrocyclone classification recovers the coarse fraction of the tailings. Coarse tailings deposit on the wall of the dam, while the fines are impounded. Decant water from the tailings pumps back to the plant as recycle process water.
The Expansion Project replaced existing pumps with larger capacity horizontal pumps in the final tailings pumping station and installed a new 25 m diameter tailings thickener. Installation of the second tailings thickener completed in April 2022.
Additional Interesting Data and Summary
A dedicated wet chemical assay laboratory operates 24 hours per day to support the plant operation. A fully equipped metallurgical laboratory is also available on site.
The Condestable Mine represents a fully operational copper processing facility with a documented expansion history. The concentrator's expansion from 7,000 tpd to 8,400 tpd involved modifications across the crushing, milling, flotation, tailings pumping, and tailings thickening areas. The processing strategy combines conventional four stage crushing with primary and secondary grinding, followed by a comprehensive flotation circuit producing filtered copper concentrate for market sale.
The plant demonstrates several recent infrastructure improvements, including the Number 9 ball mill installation with associated hydrocyclone nest and the second tailings thickener completed in April 2022. Process control relies on automatic sampling and on-line analysis through the Outotec Courier system. The tailings management approach uses hydrocyclone classification to separate coarse material for dam wall construction while impounding fines, with decant water recycled to the plant.
Key Processes
- Four stage crushing circuit with primary jaw crushers, secondary and tertiary cone crushers, and quaternary short head crushers in closed circuit with screens
- Primary grinding through nine ball mills with cyclone and Derrick screen classification to produce flotation feed at 80% passing 200 µm
- Copper rougher-scavenger flotation using 16 OK 38 cells in four banks with an additional fourth stage scavenger bank added during expansion
- Cleaner circuit with OK 8 cells in primary and secondary stages plus a cleaner scavenger
- Regrind capacity through Number 8 and Number 1 mills with an OK 20 cell processing regrind overflow
- Concentrate dewatering using two 7.62 m diameter thickeners followed by drum and disc filtration to approximately 9.5% moisture
- Tailings disposal through 25 m diameter high rate thickeners with hydrocyclone classification for dam wall construction
- On-line process analysis through Outotec Courier analyzer at mill feed, concentrate, and final tailings points
Source: NI 43-101 Technical Report, Condestable Mine, July 22, 2026. Project website: Condestable Mine
