Aluminij, based in Bosnia's southern town of Mostar and one of the Balkan country's biggest exporters, has been in trouble for years over heavy debt accumulated because of high alumina and electricity prices.
Investors with a combined $12.5 trillion in assets could review their stakes in resource companies that use storage dams if they do not release information to assess safety risks.
Numerous reports from state-run Chinese media have raised the prospect that China may limit its supplies of the minerals to gain leverage in its trade dispute with the US.