Chile's Mining Minister Laurence Golborne, left, holds a
telephone cable to be sent through a pipe to the shelter
where 33 miners are trapped alive inside the collapsed San
Jose mine in Copiapo, Chile. (AP Photo/Roberto Candia)
The 33 trapped Chilean miners who have astonished the
world with their discipline a half mile underground will have
to aid their own escape - clearing thousands of tonnes of rock
that will fall as the rescue hole is drilled, the engineer in
charge of drilling said.
After drilling three small bore holes in recent weeks to
create lines of communication with the miners and deliver
basic food and medicine, Chile's state-owned Codelco mining
company will begin boring a rescue hole on Monday afternoon
that will be wide enough to pull the men up through 700
metres of earth.
The first step will be to drill a "pilot hole" similar in
size to the other three. Then much larger machine cutters
will slowly grind through that hole, forcing crushed rock to
fall down into the mine shaft area near the trapped men.
Failure to keep the bottom clear of debris could quickly plug
the hole, delaying a rescue that officials say could take
four months.
"The miners are going to have to take out all that material
as it falls," Andres Sougarret, Codelco's head engineer on
the operation, told The Associated Press in a phone
interview.
In all, the miners will have to clear between 3,000 and 4,000
tonnes of rock, work that will require crews of about a
half-dozen men working in shifts 24 hours a day.
The men have basic clearing equipment, such as wheel barrows
and industrial-sized battery-powered sweepers, Sougarret
said. The hole will likely end up several hundred metres from
their living area in the mine's shelter, giving the men room
to manoeuvre and store the rocks, he added.
Sougarret declined to estimate how long the work would take,
saying it would depend on how each step went.
Once drilling begins, the team will have to decide whether to
fit the wider hole with metal casing, often used to seal a
hole and prevent collapses in the walls.
"We may not have to use it in this case because the rock is
really high quality, really strong," he said.
On Saturday, Mining Minister Laurence Golborne, reiterated
the government's estimate of three to four months to rescue
the men, rejecting local reports citing engineers who said it
could be done in much less time.
Golborne said that experts had analyzed 10 different methods
to get the men out.
"Up until now there is no alternative that would permit us to
get them out in 30 days," he told reporters at the mine.
While it's unclear if the government is simply trying to
under-promise and then over-deliver, there is widespread
agreement that the major drilling operation is unlikely to
endanger the miners.
"If the area where the miners are didn't get crushed in the
initial collapse, drilling this new hole isn't going to do
that," Walter Veliz Araya, the geologist who was in charge of
drilling the three bore holes, told the AP.
Mario Medina Mejia, a Chilean mining engineer not involved in
the operation, agrees.
"The question isn't whether they can safely get to the
miners," Mejia said. "It's how long can the miners wait for
them to arrive?"
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