A clump of iron ore from a mine. Picture: REUTERS
A clump of iron ore from a mine. Picture: REUTERS

Anglo American restarted its Minas Rio iron ore slurry pumping after a 15-day hiatus caused by a leak.

In a brief statement, Anglo said it had restarted operations at Minas Rio on March 27 after halting them on March 12.

Brazil’s Environmental Institute agreed to the restart after perusing documents Anglo submitted, outlining the work it had done after the leak was detected.

The leak was found in the single 530km pipeline that delivers the ore to the coast for export.

Anglo did not say how much production was lost, or what the financial implications of the leak or suspended operations were.

The break in the world’s longest slurry pipeline resulted in 300 tonnes of slurry containing 70% fine iron leaking out during a 25-minute period.

Iron is inert and is not a danger to people.

Included in the remediation work was the cleaning of the Santo Antonio do Grama creek with a crew of 200 people.

The work to clean the bed and banks of the stream would be completed by the end of May, Anglo said.

"Work will also continue on the monitoring of water quality, with periodic reports being sent to the relevant authorities," it said.

"Water supply to the city (of Santo Antonio do Grama) has been back to normal since March 15, with abstraction from the Salgado creek. On March 16 Anglo American completed the construction of a new water pipeline, offering the city a second source of water supply," it said.

Minas Rio is the most controversial mine in the Anglo stable. It cost at least $13bn to buy and build, missing capital and production targets.

It is an asset and experience that CEO Mark Cutifani uses as an example of how Anglo will never do a project again, having firstly overpaid to buy it and then making a "number of errors" in building the project.

It takes four days for the slurry to travel from the mine to the terminal, with the highly abrasive sludge moving at 6km/h down the only link to the port and a dedicated terminal.

The concentrate has a high 67% iron content. The mine will produce 26.5-million tonnes a year from 2020, three years behind schedule.