Outpouring of patriotic pride over 'Los 33' has boosted the President

Whatever the official line, there is little doubt that rescue workers are doing everything in their power to ensure that the rescue of "Los 33", as the trapped miners are known in Chile, dovetails neatly with the PR requirements of Sebastiá* Piñera, the country's President.

A charismatic billionaire, who built much of his fortune through ownership of the national television network Chilevisión, Mr Piñera has neatly escaped blame for the regulatory lapse that led to the disaster, and is hoping to benefit from the outpouring of patriotic pride that will accompany the men's rescue.

Yesterday, his wife, Cecilia, arrived at the San Jose mine, about an hour's drive from Copiapó, with reporters, and spent several hours meeting the families of the trapped miners.

Mr Piñera is anxious to join her there when the miners emerge. A helicopter is on standby at the presidential palace in Santiago.

His interest in the rescue reflects the fact that mining is embedded in the national psyche. The number of red, white and blue flags bears witness to the pride in what has so far been a slick rescue effort.

Last month, Mr Piñera scored a noteworthy coup when he met Esperanza Ticona, the four-day-old child of trapped miner Ariel Ticona. With cameras rolling, he introduced the baby to his father in a live video conference.

That helped the centre-right leader, who was elected to succeed left-winger Michelle Bachelet last November, keep his approval ratings above 50 per cent, while disapproval ratings last month fell from 36 to 32 per cent.

However Mr Piñera's efforts to be present when the men emerge could be complicated by a long-awaited European tour that requires him to leave next Sunday.

Although the tunnel is nearing completion, the countdown to the men's escape is being complicated by a decision over whether to use steel piping to line its walls. The metal would reduce the risk of a rock-fall jamming the tunnel, and prevent casualties in the event of an earth tremor, but will take time to install.

Lining the most vulnerable first 100 yards will take about four days. Lining the entire tunnel – the safest option – will take 10 days, meaning that Mr Piñera would not be there.

Opposition Senator Isabel Allende, daughter of the late left-wing President Salvador Allende, said it would be "unacceptable" to hurry the rescue to suit the President's agenda.