The rescue effort to save the 33 trapped miners in Chile was delayed on Thursday when drilling had to be halted for several hours because of geological faults.
According to Codelco’s Andre Sougarret, who is leading the operation to construct an escape route for the miners, the rock was proving to be too unstable for drilling to go-ahead.
He added that the tunnel being created to lift the men to safety had to be reinforced with cement.
The operation to reach the men is expected to take four months in total, and experts have said there will be more delays alongthe way.
Jorge Sanhueza, from the management team on the project, told The Times that the team will encounter different rock formations the further they dig, which will present their own problems.
He said: “It is impossible to extrapolate exactly how long the drilling will take because sometimes we will encounter different types of rock formation, sometimes we will need to replace a part or fix a mechanism – you don’t know what you are going to find until the drill goes through.”