Major step in Chilean mine rescue effort

Vancouver – The effort to rescue 33 miners trapped 630 metres below surface reached a milestone on Friday when a bore hole reached a passage connected to the chamber where they are imprisoned.

Now drillers will widen the hole to 71 cm in diameter, large enough to pull the men to surface. As the drill widens the hole tonnes of debris will fall down through it and the trapped miners will have to shift the fallen rock out of the way.

Two drills have been racing each other to complete the first bore hole and the piston-driven air compression drill, which chips away at the rock like a jackhammer, won against a traditional rig.

Now a much larger drill rig will take over, another piston-based system but with four hammers instead of one. Each hammer pounds the rock roughly 1,500 times per minute. The host rock of the San Jose mine is challenging to drill – it is a volcanic conglomerate with very high silica content, meaning it is very hard and abrasive.

Once the hole is complete it will be reinforced with a metal sleeve. The miners will be hoisted to surface in a capsule.

The government initially said it would take until November to rescue the men but in announcing the borehole achievement Mining Minister Laurence Golborne said the effort is “a little bit ahead,” as the initial estimate built in the possibility of more setbacks than have been encountered. He did not provide a new estimate.

Earlier, rescuers drilled three smaller holes to supply the miners with food, water, medical supplies, and extra air. The holes are also being used to enable communication between the miners and those on surface, including their families.

The men have already endured sweltering conditions for several weeks. The day before the bore hole reached its target, the trapped miners reportedly celebrated Chile’s bicentennial of independence with beef, empanadas and a Chilean flag.

The company that owns the underground mine, San Esteban, has a history of safety violations and claimed bankruptcy in the wake of the collapse. It says it cannot afford to pay the men who are trapped. Chile’s national mining company, Codelco, is conducting the rescue. Other mining companies in Chile have offered the men new jobs.