Two miners were killed when a coalmine collapsed in the suburbs of Quetta on Sunday morning.
The Sanjdi coalmine caved in after an explosion took place.
The bodies of two workers have been recovered whereas another was saved in the rescue operation.
The search of the fourth worker is underway.
At least 23 coal miners killed in May after an explosion in a mine in the Marwar coalfields.
Gas explosions are not uncommon in coal mines in Pakistan, most of which are located in Baluchistan and neighbouring Sindh, where safety measures can be lax.
The country has huge coal reserves estimated at more than 184 billion tonnes.
It produces 4 million tonnes of coal annually, most of which is consumed by brick-making kilns.
Story first published: 3rd June 2018