A RESCUE operation to free nine miners trapped since last Thursday in a mine in southern Peru could be delayed by two to three days, a top official says.

Oscar Valdes, cabinet chief to Peru's President Ollanta Humala, told reporters that getting to the miners' location could take two or three days longer than anticipated because of new roof collapses inside the Cabeza de Negro mine, about 325km south of Lima.

The miners have been trapped 250m underground in a horizontal tunnel since Thursday when a shaft collapsed.

The nine, aged 22 to 59 and including a father and son, were not injured and remain together. They were being supplied with oxygen, water and soup through a metal tube that they also use to communicate with rescue workers.

Some were able to speak with relatives who are staying near the mine at an improvised camp of about 80 people that also includes police, firefighters and other miners.

While their health was generally sound, some of the miners were suffering from anxiety, not unusual for the emergency situation and its risks.

"We are depressed. Please, get us out of here," begged Jacinto Pariona in a trembling voice from the back of the area where he was trapped with his colleagues.

His wife, Nancy Fernandez, fought back the tears as she tried to boost his spirits, chatting calmly through a hose, as rescue workers tried to rush to get the trapped men out.

"My husband told me they have been having headaches and dizziness, bone pains, and shivering. But they are not injured, and we want this work to get done fast," she said.

Authorities seemed to be cautious about taking a happy ending for granted.

In addition to Valdes, the government sent in Mining and Energy Minister Jorge Merino to try to get the crisis ironed out safely.

Outside the tunnel, a group of rescuers cut wood beams to reinforce the tunnel walls.

Workers were using buckets to remove the debris obstructing the shaft by hand, then pushing it out of the mine in a small mining car.

Before entering the mine, many are chewing coca leaves in the belief that this is helping them confront the difficult task.

"Coca gives us strengths to face the forces of the mountain," Agustin Jurado, one of the rescuers, said. "These hills emit dangerous gases, and coca defends us from them."

Leaves of the coca plant are the main raw material used to produce cocaine.

The rescuers were thought to be only about two meters (6.5 feet) from the miners on Saturday when more cave-ins slowed the pace of the operation and workers had to focus anew on shoring up the chamber to avoid a larger cave-in.

"Due to the cave-ins late Saturday we don't know exactly the distance between rescuers and the miners but communication has been maintained constantly," said Erin Gomez, a provincial civil defense manager.

Cabeza de Negro is an unlicensed mine that was abandoned more than two decades ago by its owners, but continues to be exploited.

Informal artisanal mining has been on the rise in recent years in Peru, one of the largest producers of silver, copper and gold.

The Peruvian miners' fate recalled a similar case in Chile that made world headlines. In August 2010, 33 miners were trapped after a cave-in in the San Jose gold and copper mine in northern Chile - after 69 days and a spectacular rescue operation with the world watching, they were brought out safely.

Originally published as Trapped miners: 'Please, get us out of here'