Newrest starts site services contract at Mina Justa; EPCM contractor Ausenco making good progess despite COVID-19

Newrest Peru recently started food and facility management services for more than 1,200 workers in Mina Justa, one of the main greenfield cppper mining projects in Peru which is starting production this year. The mine is in the District of Marcona, which is in the province of Nasca in Ica Region, at an altitude of 800 m about 400 km southeast of Lima.

The company said: “It was a great challenge to mobilise and organise the opening in 45 days considering the challenges involved in making this implementation in the midst of the juncture generated by COVID-19. We appreciate Marcobre’s trust in us and are confident that this is the beginning of a strong and lasting relationship with them.”

Mina Justa is a new copper mine with two open pits plus two processing facilities with an expected production of about 102,000 t/y of copper contained in concentrate and 58,000 t/y of copper cathodes. Ausenco is the EPCM contractor for the project. The mine plan was developed to allow the oxide and sulphide ore bodies to be processed simultaneously, enhancing project economics by targeting the higher-grade sulphide ore early in the project cycle. The plants will process 6 Mt/y of copper sulphide ore and 12 Mt/y of oxide ore via solvent extraction and an oxide leaching facility.

In the final layout, the main pit will comprise an area of 244 ha approximately; and will be 2 km long by 1.5 km wide, and 500 m deep. The Manto Magnetita pit will comprise an area of 21 ha approximately; and will be 700 m long by 300 m wide, and 120 m deep. The two pits will have 12 m high benches and 22 m wide ramps.

The oxide ore will be processed by vat leaching to produce a pregnant liquor, followed by solvent extraction and electrowinning to produce a copper cathode. Due to the acid consumption in the oxide plant requiring significant operating costs, the oxide plant design incorporated novel crushing and leaching technology to reduce acid consumption and optimise operating costs. The sulphide ore will be processed by conventional flotation to produce copper concentrate. Both processing plants will operate using seawater to limit freshwater consumption which will be desalinated before use.

Ausenco says the plant layout and general arrangement were optimised to achieve substantial reductions in the quantities of bulk materials compared with contemporary designs in North and South America, leading to cost-effective processing plants. The design includes two HPGR systems, one for each of the oxide and sulphide ore systems.

In February, Ausenco said Mina Justa had surpassed 10 million person hours without a Lost Time Incident (LTI) of which it contributed 6.5 million of these hours as part of its EPCM work.

In terms of mining equipment, ZAMine, the local dealer and distributor for Hitachi mining equipment in Peru, delivered the three EX5600E-6LD (electric face shovel) machines in mid-2019. The truck fleet includes 26 232 t class Cat 793D trucks supplied by dealer Ferreyros.

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