A general view shows the 550-metre-deep Vostochny opencast of the Olimpiada gold operation, owned by Polyus Gold International company, in Krasnoyarsk region, Eastern Siberia, Russia, June 30, 2015. Polyus Gold International is the largest gold producer in Russia and one of the top 10 gold miners globally by ounces produced, according to the official web site of the company. Olimpiada is Polyus Gold's largest operation. (Photo by Ilya Naymushin/Reuters)

A view shows explosions, part of the mining technology, at the 550-metre-deep Vostochny opencast of the Olimpiada gold operation, owned by Polyus Gold International company, in Krasnoyarsk region, Eastern Siberia, Russia, June 30, 2015. (Photo by Ilya Naymushin/Reuters)

Employees walk along lines of parked Caterpillar 136 tons load-carrying capacity dump trucks before the beginning of the working shift at the Vostochny opencast of the Olimpiada gold operation, owned by Polyus Gold International company, in Krasnoyarsk region, Eastern Siberia, Russia, June 30, 2015. (Photo by Ilya Naymushin/Reuters)

An engineer (L) talks to a driver of a dump truck loaded with gold-bearing soil at the Vostochny opencast of the Olimpiada gold operation, owned by Polyus Gold International company, in Krasnoyarsk region, Eastern Siberia, Russia, June 30, 2015. (Photo by Ilya Naymushin/Reuters)

Dump trucks loaded with gold-bearing soil drive at the bottom of the 550-metre-deep Vostochny opencast of the Olimpiada gold operation, owned by Polyus Gold International company, in Krasnoyarsk region, Eastern Siberia, Russia, June 30, 2015. (Photo by Ilya Naymushin/Reuters)

A view shows explosions, part of the mining technology, at the 550-metre-deep Vostochny opencast of the Olimpiada gold operation, owned by Polyus Gold International company, in Krasnoyarsk region, Eastern Siberia, Russia, June 30, 2015. (Photo by Ilya Naymushin/Reuters)

An aerial view from a plane shows the Titimukhta gold operation, owned by Polyus Gold International company, in Krasnoyarsk region, Eastern Siberia, Russia, July 1, 2015. (Photo by Ilya Naymushin/Reuters)

An excavator loads a dump truck with gold-bearing soil at the bottom of the 550-metre-deep Vostochny opencast of the Olimpiada gold operation, owned by Polyus Gold International company, in Krasnoyarsk region, Eastern Siberia, Russia, June 30, 2015. (Photo by Ilya Naymushin/Reuters)

An aerial view from a plane shows the Blagodatnoye gold operation, owned by Polyus Gold International company, in Krasnoyarsk region, Eastern Siberia, Russia, July 1, 2015. (Photo by Ilya Naymushin/Reuters)

An aerial view from a plane shows the Olimpiada gold operation, owned by Polyus Gold International company, in Krasnoyarsk region, Eastern Siberia, Russia, July 1, 2015. (Photo by Ilya Naymushin/Reuters)

Dump trucks loaded with gold-bearing soil drive from the bottom of the 200-metre-deep Titimukhta gold operation, owned by Polyus Gold International company, on the way to a procession plant in Krasnoyarsk region, Eastern Siberia, Russia, June 30, 2015. (Photo by Ilya Naymushin/Reuters)

Employees walk near rotating crusher equipment inside a gold procession plant at the Olimpiada gold operation, owned by Polyus Gold International company, in Krasnoyarsk region, Eastern Siberia, Russia, June 30, 2015. (Photo by Ilya Naymushin/Reuters)

Employees speak near the crusher of a procession plant (back) of the Olimpiada gold operation, owned by Polyus Gold International company, in Krasnoyarsk region, Eastern Siberia, Russia, June 30, 2015. (Photo by Ilya Naymushin/Reuters)

A melter casts an ingot of 92.96 percent pure gold at a procession plant of the Olimpiada gold operation, owned by Polyus Gold International company, in Krasnoyarsk region, Eastern Siberia, Russia, June 30, 2015. (Photo by Ilya Naymushin/Reuters)

A melter casts an ingot of 92.96 percent pure gold at a procession plant of the Olimpiada gold operation, owned by Polyus Gold International company, in Krasnoyarsk region, Eastern Siberia, Russia, June 30, 2015. (Photo by Ilya Naymushin/Reuters)

A melter places an ingot of 92.96 percent pure gold at a procession plant of the Olimpiada gold operation, owned by Polyus Gold International company, in Krasnoyarsk region, Eastern Siberia, Russia, June 30, 2015. (Photo by Ilya Naymushin/Reuters)