The incident happened in the Lenin mine belonging to ArcelorMittal, Ruslan Imankulov, a spokesman for the country's emergency ministry, told AFP.
"A sudden release of gas during the drilling of a drainage well led to the deaths of five workers," Imankulov said, adding "Four people were hospitalized and 106 were evacuated".
A government commission has opened an investigation to probe whether there were any potential violations of safety rules.
Governor of Karaganda, the place where the mine is located, said the accident had been caused by an "explosion of methane". The gas, when combined with a certain amount of oxygen, can combust.
Meanwhile, Kazakh President Kassym-Jomart Tokayev offered his condolences to the families and friends of the deceased workers and wished a "speedy recovery to the injured".
RHM/PR