As follow-up to the audit, the environment minister issued two decrees that gave Freeport six months to overhaul management of its mine waste at Grasberg.
However, the Canadian Mining Eye index — which tracks the performance of 100 Toronto Stock Exchange and TSX Venture Exchange mid-tier and junior mining companies — dropped 8% in the three months to March 2018.
The Association of Mineworkers and Construction Union (AMCU) said the company failed to take precautions two avoid injuries at its mines earlier this week.