Forty-five former managers and employees of a mine in the western Turkish town of Soma have gone on trial on charges relating to the country's worst mining disaster last year that left 301 miners dead and exposed major safety shortcomings in the industry.

The opening hearing of the trial on Monday was tense with lawyers and families of the victims protesting authorities' decision that eight of the jailed defendants - who are ex-top managers of the Soma Komur Isletmeleri AS mining company charged with murder - should not attend the trial over security concerns.

The trial is taking place in the town of Akhisar. The eight ex-managers, who are in detention in Izmir, had been seen on a large screen in the court sitting on benches surrounded by police at their prison. 

The court called a recess and then adjourned until Wednesday, demanding that the eight defendants be present at the next hearing, the state-run Anadolu news agency reported.

The main suspects on trial include the CEO and the general manager of mine company Soma Komur Isletmeleri AS, who have been charged with "probable voluntary manslaughter" over the 301 deaths and causing "bodily harm" to the 162 injured.

They face up to 25 years in prison for each of the victims and an additional six years for each injured.

Thirty-seven other people have been charged with negligent death and injury and face up to 15 years in prison.

The mining disaster happened when one of the pits of the Soma mine became engulfed by flames and carbon monoxide gas, trapping a team of some 800 miners working inside.

Inspection reports said the coal had been smouldering for days before the May 13 disaster, releasing toxic gases.

A report after the disaster found a long list of faults at the mine, including a lack of carbon monoxide detectors, gas masks in poor condition and bad ventilation.

Lawyers for the families of the victims say that the owners of the Soma mine had sought over-exploitation for the sake of profit, resulting in "working conditions worthy of slavery".

Source: Agencies