The Pike River Mine manager says recovery teams have made their way through hundreds of metres of the mine.
Six-person teams from the Mines Rescue Service entered the mine on Tuesday for the first time since explosions killed 29 men.
The bodies of the workers have remained in the West Coast mine since the disaster on 19 November last year. The mine has been in receivership since December.
The first recovery team was expected to enter the mine about 10am on Tuesday but the statutory mine manager, Steve Ellis, says it took them nearly two hours to break the concrete seal around the temporary entrance.
Mr Ellis told Checkpoint the team went about 300m into the mine and found little damage to the inside of the shaft.
"The conveyor structure is in place, as are the pipes, there's one or two cables down from the roof, which is to be expected, but there's no great signs of explosion."
Mr Ellis says the conditions have been perfect inside the mine and he is pleased the operation has gone as planned.
The teams found a site for a temporary airlock, and left the mine after two hours.
The plan is to travel all the way down the 2.3km shaft in steps of several hundred metres at a time.
A second team has since entered to put gas monitoring equipment, and the first team is going back on Tuesday evening to prepare to further prepare the seal.
A spokesperson for the Pike River families says they have pushed hard to get the receivers to agree to enter the mine and the operation is not before time.
Bernie Monk says the families realise it will be months, and possibly up to two years before their men are recovered, although he believes progress will be faster than expected.
Carol Rose, whose 31-year-old son Stuart Mudge died in the mine, says the entry is seven months' late, but very welcome.
Good development - PM
The Prime Minister says the ability to enter the Pike River mine is a welcome development.
John Key said from India, where he is on a trade visit, the decision to go into the mine was left up to the experts, as he doesn't have the knowledge to make that call.
Mr Key says he realises that as well as losing their loved ones, the waiting has been very tough on the families.
