Rescue workers in Chile have been prevented by a new cave-in from reaching 33 miners trapped underground.
Instead, an attempt has begun to drill holes to provide the miners with food, water and oxygen.
The rescuers also plan to lower sound detection equipment through the holes to try to locate the miners.
No contact has been made with the miners since a tunnel collapsed on Thursday at the San Jose mine, near the city of Copiapo in northern Chile.
The miners were working at a depth of around 450m (1,475ft) and officials hope they took refuge in a shelter stocked with oxygen food and water.
The mine is owned by the private firm San Esteban, which said on Sunday that 33 miners were trapped, not 34 as was originally believed.
Three teams were attempting to reach the trapped miners using a ventilation shaft when it was blocked by a cave-in.
Mining Minister Laurence Golborne said it could now take at least a week to reach the miners.
Chilean President Sebastian Pinera said every effort would be made to find them.
"I personally promised the families of the trapped miners the rescue operations will continue with all the strength in the world," he said on Sunday in the capital Santiago, a day after meeting relatives of the trapped workers at the mine.
"I also pledged to thoroughly investigate, establish where responsibility lies, and punish accordingly."
Major mining accidents are uncommon in Chile, the world's top copper producer.
Officials said the roof of the main ramp down into mine was thought to have collapsed on Thursday, around 100m (328ft) above the miners' heads.
Some 130 rescue workers are trying to reach them, but progress has been hampered because the main entrance is blocked. The ventilation shaft had been the main hope of reaching them.