Move would seek to secure approval for its friendly merger with smaller rival Agrium, creating the world’s largest potash miner worth about $36 billion.
The miners from the Eldorado Gold mine in the Halkidiki region were protesting looming layoffs as the company said Monday it would suspend all operations in Greece.
Citing delays in permits from the Greek government, the company said no additional investment would be made into the Olympias and Skouries projects or the Stratoni mine, which it acquired in 2012.
South Africa holds the world's biggest reserves of platinum, chrome and manganese, but investment in the sector has dropped in each of the past two years as a result of increasing legal uncertainty and labour disputes.
Gokhran, part of Russia's finance ministry, was influential on the global platinum group metals markets in the 1990s and 2000s, when palladium stocks it accumulated during the 1970s and 1980s came to the market and depressed prices.
The London Metal Exchange sought on Thursday to win back trading volumes by proposing a cut in fees for trades crucial to its physical user base as rivals gear up to offer alternatives.