COPIAPO, Chile  — Chilean President Sebastian Pinera on Sunday paid a visit to a Chilean mine where 33 miners have spent more than a month about 2,300 feet underground following a mine collapse.

“We have done everything possible, and we have done our best to rescue them alive,” Pinera said, speaking in English. “We will succeed in this tremendous effort. When we do not know, but it will be sooner than what you expect.”

“When our people unite behind a great and noble cause, there is no one or no thing that can impede us from our objectives,” he said.

The San Jose mine, in Chile’s northern Atacama Desert, caved in on August 5. The men were initially feared dead, but tied a note to a drill bit on August 22 and sent it to the surface to signal they were alive.

Pinera also visited with the families of the trapped miners Sunday, presenting them with a gift — a copper plate engraved with the contents of that note, “We’re fine, in the shelter, all 33.”

“Hopefully this spirit of unity, faith, confidence and pride to be Chilean that is in the air at the San Jose mine and in every corner of Chile is a spirit that will illuminate this third century of independence,” Pinera said, referring to Chile’s recent bicentennial celebration.

The president arrived at the mine at mid-morning Sunday, flying in on a military helicopter that landed in the desert, kicking up dust.

He met 5-day-old Esperanza Ticona, the daughter of Ariel Ticona, one of the trapped miners. Esperanza was brought to the mine for the first time Sunday by her mother, Elizabeth Segovia.

Pinera also held a teleconference with the miners, via a cable that has been strung from the surface half a mile deep into the men’s shelter. He said the men were in good spirits.

The president spent about an hour and a half at the mine, in all.

Away from reporters, Pinera first visited a powerful oil drill that has been transported to the mine to assist in the rescue. The drill, known as Plan C, began operating Sunday. Mine experts say it could be the fastest way of punching a hole through rock that is wide enough to hoist the miners back to the surface.

Two other drills, a Schramm T-130 (Plan B) normally used for boring water holes and a Raise Borer Strata 950 (Plan A) normally used for drilling ventilation chimneys in mines have been operating for about three weeks.

On Friday, the Schramm T-130 reached a depth of 2,044 feet and penetrated the roof of the workshop area close to the miners’ shelter. However, the shaft is only about 12 inches wide and the drill must make a second pass to widen the hole to a maximum 28 inches.

Sunday was the first day that all three drills were working simultaneously, Pinera said.

— CNN’s Karl Penhaul contributed to this report.