JAPANESE rescue workers failed yesterday to dynamite a giant boulder off a collapsed road tunnel where 20 people were entombed in a bus and a car, and hope had almost run out of finding the victims alive.
Rescue operations were called off until this morning by which time the trapped people would have spent two days in their icy tomb buried under tons of rocks and mud from a winter landslide.
The blasting operation was a last ditch gamble to reach the victims - 19 in the bus and one motorist - who have been trapped since Saturday morning in the tunnel on Japan's northernmost island of Hokkaido.
Relatives gave permission for the blasting operation after round the clock efforts in light snow to reach the vehicles from either side were thwarted by tonnes of fallen rock.
The collapse happened when a giant tear shaped rock slab slid off the side of a mountain overlooking the tunnel and speared into the roof, opening a breach through which poured tonnes of debris at about 8 a.m. on Saturday (2300 GMT Friday).
Rescue workers hoped that if the boulder could have been blasted off the roof they might have been able to reach the vehicles from the tunnel roof.
Workers, who were only able to see the scene through special scanning equipment poked through debris, said the front and back of the bus were crushed and there were no sounds or signs of movement.
They were able to see the bus driver's hat and one hand but calls to him went unanswered.
When the rock slab fell, a 40 metre stretch of the ceiling crashed down from just inside one of the entrances of the 1,086 metre Toyohama tunnel about 30 miles north west of Hokkaido's capital city of Sapporo.
The rupture started before the tunnel burrows into the mountain through which it passes on a highway running along the Sea of Japan coast between the towns of Yoichi and Furubira.
Rescue workers estimate the slab of rock responsible for the breach weighs about 50,000 tonnes.
Authorities said they would aim to conduct a second blast before noon today. Preparations would be made overnight, they said.
Geology experts said landslides were a constant hazard on Hokkaido.
A police spokesman said all family members of the victims had given their consent to the blasting operation and were aware it could have caused a new collapse which would have made the plight of their loved ones even more desperate.
However, most relatives already appeared steeled for bad news even before the dynamiting was carried out.
Rescue workers planted a total of 500lb of dynamite at 21 points in the slab, but after detonation the boulder had moved only about a foot off the tunnel roof, leaving most of it still on top.
"We did not achieve our aim of removing the boulder because we cut the amount of dynamite for safety reasons," a rescue official said.