Mine officials say the incident is believed to have involved a gas blow-out—a sudden and powerful release of gas.
The mine’s rescue team has been dealing with the incident and emergency services are at the scene.
Her Majesty’s Mines Inspectorate has also been informed of the incident.
A spokesman said: "Company staff will be offering all possible support to the man’s family. All other workers in the mine at the time of the incident were safely evacuated."
More information to follow.