The two tied for first place in the WWF's environmental responsibility assessment of Russian metals and mining companies.

The WWF, in collaboration with the United Nations Development Programme, Global Environmental Facility, and the Ministry of Natural Resources and Environment of the Russian Federation, ranked 33 companies on three categories: environmental management, environmental impact and disclosure/transparency.

Polymetal's result was quite a change from last year when the company placed seventh in the rankings.

Its chief sustainability officer Daria Goncharova said: "First place in this rating is the result of our multi-year effort to improve sustainability at Polymetal. The result reaffirms our approach in favour of complex and best-practice measures that form a crucial part of our strategy."

Kinross operates the Kupol and Dvoinoye underground mines in Russia, while Polymetal has seven operating mines and a handful of exploration projects in the country.