Four workers have been killed by a methane gas explosion at Norilsk Nickel’s Zapolyarny mine in Russia's Polar region, with several others injured. 

According to the company, the explosion was caused by a build-up of methane gas at a mine shaft when personnel from contractor Polar Construction Company were carrying out drifting activities at the site. 

Norilsk Nickel Polar division health and safety deputy director Sergey Gradyushko said: "IOur priority is on safe evacuation of other workers who were on site.

"This is a serious situation, but one for which the company has a prepared response plan which is now underway."

Following the explosion, other miners working at the site were pulled to safety, with emergency services and rescue teams rushed to the site. 

"This is a serious situation, but one the company has a prepared response plan for, which is now underway."

The company said that it is in the process of an investigating the explosion's cause.

The suspension of work after the incident is not expected to have an impact on output.

Norilsk Nickel is a diversified mining and metallurgical company producing nickel, palladium platinum, cobalt, copper and rhodium. 

In addition, the company produces gold, silver, iridium, selenium, ruthenium, and tellurium.

Image: A Norilsk Nickel mine. Photo: courtesy of Norilsk Nickel.