Madrid -- Heavy machinery has been brought in by rescuers in southern Spain who plan to drill vertical tunnels next to a deep borehole to reach afor five days.
"The terrain's geology is complicated, and that's slowing down the works," said Angel Garcia, the leading engineer coordinating the search-and-rescue operation, on Friday.
Spaniards are holding their breath with every setback in the against-the-clock race to reach Julen Rosello, who fell into the 360-foot-deep waterhole on Sunday.
Unable to go down the narrow shaft, rescuers used machinery first but found a blockage some two thirds of the way down and are now trying to drill alternative tunnels to reach the boy.
Garcia, head of the provincial civil engineers' association, told reporters at the site that workers would dig two parallel vertical tunnels, a plan hatched after a horizontal hole bored earlier in the week from a hillside ran into heavy stone.
Authorities say there are hopes Julen could still be alive if there is enough oxygen under the obstruction.
According to CBS News partner network BBC News, the same family lost another son to some kind of accident less than two years ago. There has been no sign of life from the boy from inside the borehole.
"I still have hope that my son is alive," Julen's father Jose Rosello was quoted as saying by Spain's newspaper El Pais on Wednesday. "We can't stop until we get my son out of there."