Four mineworkers were killed as a result of coal gas poisoning and cave-in at two underground coal mines in the northern province of Zonguldak on Friday.

There miners reportedly lost their life in a methane gas blast at a privately-owned mine in the Black Sea province of Zonguldak. An initial police investigation found that the mine was operating illegally.

Another miner was killed and one other was wounded as a result of cave-in at a state-run mine in the same province on Friday.

One miner was also killed in a cave-in in the northern province of Ordu today. The man, Hasan Hüseyin Deniz (25), lost his life after he got trapped under a rock, which weighted some fifty tons, workers quarried from the mine to be used in the construction of Ordu-Giresun Airport.

Eighty mineworkers in Turkey were killed in preventable work accidents in the first 11 months of 2013.

300 miners working for the Üzülmez Company affiliated to the Turkish Hardcoal Authority (TTK) went on strike in Zonguldak in mid November to protest against severe working conditions and the security system, including cage and wire fence, that has recently been placed in the entrance of their working area, denying them permission to enter or leave the mine before and after the beginning and ending of working hours, even if they arrive one minute late.

The protest began after the miners on the night shift refused to leave the mine in the morning. They were later joined by the miners on the morning shift who did not enter the mine to support the workers' demand for the improvement of severe working conditions.

Genel Union of Miners (GMİS) Secretary Osman Tutkun said that the protest was started as a consequence of the inhuman working conditions, repression and psychological pressure miners have faced for a long while.