Norway fund may have to offload $1bn stake in Glencore in shift away from coal

All of the tailing dams are located in the Brazilian state of Minas Gerais.

In April, ethical investors working on a global standard for tailings dams had written to 683 listed resource companies, including major miners, asking for information to be made public within 45 days about every facility they control.

The company's latest proposal includes a slightly higher signing bonus than previous offers, union officials said.

The international group says sales of polished diamonds below 0.50 carats are slow due to excess supply, weak Chinese demand and tight Indian liquidity.

EcoMag says hydrated magnesium carbonate is a high-purity, high-value magnesium product that currently fetches circa $1,250/tonne.

The causes that prompted a rock to fall down at the Pilar Norte mine are under investigation.