The evacuation of 33 miners trapped underground in Chile is likely to start on Wednesday, the country’s mining minister has said.

Laurence Golborne was speaking after engineers had drilled through to the underground chamber where the miners are sheltering.

Work has now begun to stabilise the top of the rescue shaft with steel casing, which will take about a day-and-a-half.

The miners have been trapped 700m (2,300ft) underground since 5 August.

The drilling breakthrough came shortly after 0800 local time (1200 GMT) on Saturday, sparking celebrations across Chile.

Speaking at a news conference outside the San Jose mine, Mr Golborne said the decision had been taken to reinforce 96m of the top part of the newly completed shaft.

He said that 16 steel tubes would be lowered into the shaft one by one.

The minister said that the rest of the shaft was exposed rock and did not need to be strengthened.

Once the casing is put together, officials expect it will take 48 hours to put the rescue capsule in place.

The BBC’s Rajesh Mirchandani, who is at the mine says a winch-and-pulley system has to be set up before the capsule, named Phoenix, can be lowered into the shaft.

Such an operation has never been tried before, he says.

The miners will then be brought up one by one in three groups: the fitter ones first, then the weaker ones, and finally the strongest of the group.

But the evacuation will begin only after a doctor – who will be lowered to the chamber – has examined the miners.

Mr Golborne said the evacuation of the first miner was likely to start on Wednesday, although there was a chance that the rescuers would be able to proceed on Tuesday.

“The process of rescue should last for two days, or it will take in the range of 48 hours: the whole process from the first miners to the last one.”

The minister added that “so far everything has gone smoothly”, but admitted that the operation was not “without risk”.

He also said that the miners were “in great spirits and relaxed”.

They have been living in the shelter 700m underground since the collapse in August. However, the Plan B drill – the second of three which have been working simultaneously – penetrated 624m to a workshop which can be reached by the miners.

Mr Golborne said the rescuers were also continuing work on another, wider shaft, using the Plan C drill, as a back-up.

The miners’ ordeal (now in its 66th day) is the longest suffered by a group of miners caught underground.