An arbitration claim by Kappes, Cassiday & Associates against Guatemala relating to the suspension of the company's Tambor gold asset is registered by a World Bank body.
The mining company of former tycoon Eike Batista had its capital reduced by 99.4%.
Overall, mineral shipments to fellow bloc members Argentina, Paraguay and Uruguay, performed well in the first 11 months, official data shows.
Like local steel industry, the ratings agency also forecasts better times ahead for the country's main producers.
Companies operating in Brazil, Chile, Mexico and Peru published results from their exploration programs.
The miner will pay nearly US$2.27mn to own 60.6mn shares, maintaining its interest in Reunion at around 15%.
BNamericas' latest Mining Intelligence Series report takes a close look at the trends shaping mining investment and the most important socio-political developments to watch in the year ahead.
The Australian and the Japanese companies approved the final investment decision for the stage 2 expansion of the lithium facility in Argentina.