Another eight workers are reported to be missing. Three miners were recovered alive.
Some 374 people were in the mine, in the central region of Qaraghanda, when the blast occurred.
The mine is operated by Mittal Steel Termitau, a subsidiary of the world's largest steel producer, Mittal Steel.
The regional prosecutor's office has opened a criminal investigation to determine the cause of the blast, which occurred at a depth of 620 meters.
One Kazakh politician Dos Koshim, who runs a nongovernmental organization known as Network of Independent Observers, has already blamed "negligence and the search for profit on behalf of foreign investors and local authorities" for the disaster.
"Unfortunately, they don't care about the most important thing, that is the safety of miners," Koshim said. "Events such as this have become more and more frequent in our industry in recent years."
The Interfax-Kazakhstan news agency quoted lawmaker Mukhtar Tinikeev as making similar accusations.
(Kazakhstan Today, Interfax-Kazakhstan)