Cecilia Jamasmie , Senior Editor

Decision comes after the companies received Wednesday a preliminary geological assessment of the property, which shows Heritage contains several targets for modern alluvial diamond placer deposits.

The Rajo Inca project would convert the existing asset, which has been in operation since 1959 and is due to run out of ore in 2021, to an open pit mine from an underground one.

Operations will resume before year end, but a planned ramp-up to 26.5 million tonnes per year is likely to be pushed back to 2021 from 2020.

CEO Fabio Schvartsman said the company would only invest further in nickel if global prices for the metal rise from $13,000 per tonne currently to around $20,000 per tonne.

Researchers from Curtin University discovered reidite, one of the rarest minerals on Earth buried deep within an ancient meteorite crater in Western Australia.

First production from the $5.3 billion underground expansion of Oyu Tolgoi was originally scheduled for early 2020.

The goal is to reduce reliance on batteries from Asia, particularly China and South Korea.

Overall project engineering at the 270,000 ounce-a-year Guyere gold project, which is already more than A$100 million over its original budget of A$507 million, is now 96 percent complete

The company also said it would reconfigure the mining methods used at Hail Creek, a process that will be phased in over the next 18 months.

Chile's Codelco is in the midst of upgrading its smelter at Chuquicamata, its second largest operation by size, to comply with stricter emissions standards coming in effect in December.