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Broken drill bit hampers Chile mine rescue

Chile’s mining minister has acknowledged that a problem has stalled the most advanced of three tunnels being drilled to 33 miners trapped underground and said officials might have to restart the bore hole in another location.

But Laurence Golborne insisted that the setback is within the range of problems foreseen by authorities before the rescue began, and does not significantly alter the expected time line for getting the men out.

Work on boring the hole stopped last week when a drill struck an iron support beam for a mine shaft at about 900ft, destroying a drill bit. A replacement part was rushed from the United States, but engineers have so far failed to recover all of the broken metal using magnets.

“If we are unable to remove that bit, the hole would not be able to continue,” Golborne said.

He said authorities planned three bore-holes from the beginning precisely in anticipation of such problems, andhe met with relatives of the miners today to assure them that the rescue is still on track.

“I have heard that (the miners) are showing some worry, but they understand and this has been explained to them,” Golborne said.

From the time they first made contact with the miners 22 August, some 17 days after the massive undergroundcollapse, authorities have said a rescue could take up to four months.

Mining experts have called that time line conservative, and it apparently takes into account the possibility ofsetbacks such as the broken drill bit.

Meanwhile a second drill that went off-line on Friday for routine maintenance resumed operating today.

And workers are busy prepping the so-called Plan C – an oil-well drill so big it took 40 trucks to transport.

Crews at the mine had to level rocks and lay a concrete platform over an area nearly the size of a football field on the hilltop, where only a dozen trucks at a time have room to unload.

Taking nearly two weeks just to set up, the Plan C drill will be nearly 150ft tall when assembled. It is the fastest of the three, capable of reaching the miners in 45 days once it comes online.

The main shaft at the San Jose gold and copper mine in northern Chile collapsed on 5 August, trapping the miners more than 2,200ft below ground.

Rescuers have opened multiple narrow bore-holes to the miners which they use to pass them food, water, oxygen, electricity and messages.

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