The biggest suspects of the proceedings face manslaughter or bodily harm charges, with 162 miners also injured in the disaster last year.
These eight already-incarcerated defendants, which include the CEO and general manager of the Soma-based coal company, face up to 25 years jail time for each of the dead plus six years for each of the injured.
They did not attend the trial out of security concerns, triggering some protests, but the Turkish Anadolu Agency news wire reported that they would be at the next hearing tomorrow.
The other 37 people in the trial are facing charges related to negligence which could give them sentences of up to 15 years.
The mining disaster started with an underground explosion during a shift change on May 13, 2014, with 787 people underground at the time.
The resulting fire burned until May 15 while most of the victims died of carbon monoxide poisoning with many of them trapped underground following the explosion.
