More than 30 miners were trapped in the mountainous Orakzai tribal region after a shaft collapsed amid heavy downpours on Saturday, according to the political administration of the district.
Governor Khyber Pakhtunkhwa in a statement has termed the mine explosion a ‘natural disaster’.
The surviving labourers have said that the digging in the coalmine has been illegal.
On Sunday emergency responders were struggling to rescue two missing miners, with officials saying it was unclear whether they were still alive.
A military statement issued late Saturday said more than 100 troops from the army and paramilitary Frontier Corps were helping to operate heavy machinery at the site and providing medical support.
“Apparently torrential rains were the main cause of the collapse but usually the management of such coal mines do not care about safety standards,” the political agent of Orakzai region Zubair Khan said.
The mines in Pakistan are notorious for poor safety standards and bad ventilation.
At least 43 workers were killed in March 2011 when explosions triggered a collapse in a coal mine in southwestern Baluchistan province, which is rich in gas, oil and mineral deposits.