NZ miners died in initial blast
Chief coroner Neil MacLean said evidence showed the men died from a combination of concussion, burns or hypoxia caused by gases and a lack of oxygen.
Earlier this month, officials said they abandoned attempts to recover the bodies because the mine is considered too dangerous and unstable.
A buildup of gases prevented rescuers from entering the Pike River mine outside Greymouth after the November 19 methane-fueled blast.