In a press conference, representatives from Soma Holding defended their response to the disaster and said their priority had been to save lives.
They added that an unexplained build-up of heat in the mine appeared to have caused the collapse.
It was Turkey’s worst-ever mine disaster and has sparked angry protests against the government.
There are thought to be up to 18 workers still trapped inside the mine, according to Turkish ministers and Soma Holding. It is not clear if the men are still alive.
Another 122 are injured, while 363 escaped safely.
Speaking to journalists, plant manager Akin Celik said: “We still do not know how the accident happened. There is no negligence of ours in this incident.”
He added: “We want to find answers as well. We have never faced such conditions, such circumstances. We haven’t slept for three days because we’re first trying to save lives.”
Soma Holding executives said it was not clear what caused the explosion and collapse.
However, General Director Ramazan Dogru said reports that the fire began at a transformer were wrong.
“Overheating led to a collapse” at another part of the mine, he said, adding that this caused a fire which rapidly expanded. He said it was not clear why the overheating had occurred.