Work stopped completely at Kellingley after Tuesday's incident
Work is continuing to make parts of Kellingley pit safe after a gas blast led to the evacuation of 218 miners.
It is thought the explosion was caused by spontaneous combustion of methane when temperatures hit critical levels.
Nitrogen has now been pumped into the affected area to starve it of oxygen and to help normalise the atmosphere.
Chris Kitchen from the National Union of Mineworkers (NUM) at Kellingley said: "We are hoping miners will go back down within the next 48 hours."
UK Coal, the company which owns Kellingley, told BBC Radio Leeds that the overnight pumping work following the incident was part of a recovery process which would take "as long as it takes" to get the pit back into production.
Work was halted on Tuesday after miners reported a loud noise near an area where coal was being extracted.
Chris Kitchen, NUM Yorkshire area secretary, said the evacuation of Kellingley following the blast showed safety procedures were effective.
He said: "The timing of the incident could not have been worse. We had two shifts underground, that's 218 men.
"All of them returned to the surface safely with no casualties so that is the big positive - that the evacuation procedures do work."
Officials from the government's Mines Inspectorate have been called in to investigate the incident at Kellingley.
Chris Kitchen said the NUM had worries over what happened in the time leading up to the explosion.
He said: "Our concern is that we did not have any prior notice of the heating which ignited the build-up of methane and caused the explosion.
"It is extremely concerning for us because obviously we have some of the most stringent coalmining safety systems in the world.
"For heating to occur and to have got to the state where it could ignite gas and put the pit in jeopardy is very concerning."
Kellingley is the largest remaining deep mine in Yorkshire with its two main shafts almost 800 metres deep.
Chris Kitchen said with recent events in Chile and the mining tragedy in New Zealand, the incident at Kellingley was a reminder that mining is still a dangerous industry.
He said: "At the moment the men do not seem to be adversely affected by it, but obviously it is part of the danger which is always present.
"You know these risks when you go into coalmining because of the added danger of methane."
Mr Kitchen said he hoped investigations into the incident would mean Kellingley and other pits could become even safer.
He said: "We want to ensure that we tighten everything up and make sure that it cannot happen again.
"There will definitely be an investigation into how it happened.
"There will also be inquiries into how we can can put new safety systems in - or tighten up on safety systems - to prevent it happening again in the future."