Expert Driller Saved Chilean Miners in Gripping, International Rescue Effort
Jim Stefanic, operations manager of Chilean drilling company Geotec Boyles Bros., led the drillers who successfully bored and then widened the “plan B” rescue shaft that became the path to life for 33 Chilean copper miners trapped for 69 days nearly a half-mile underground. The rescue that gripped the world happened last fall in the San Jose Mine, located about 28 miles from Copiapo in northern Chile.
Estimated at 700,000 tons of rock, the cave-in on Aug. 5 had trapped the miners in a deep section of the mine beneath the Atacama Desert in northern Chile, nearly 500 miles north of Santiago. They were rescued on Oct. 13 after Geotec reamed a 2,040-ft-long, 5½-in.-dia pilot hole to 28 in. dia. It then could accommodate the rescue capsule that carried each miner from the rock prison up to the earth’s surface, where each was reunited with loved ones.
The Chilean rescue is thought to be the deepest-ever retrieval of trapped underground miners. At 69 days, it also represents the longest that trapped miners have survived underground.
After the collapse, in order to find out where the miners were and whether they were alive, state-owned mining company Codelco asked Geotec and seven other drilling companies to drill pilot shafts from the surface to likely places the missing miners might have taken refuge, says Stefanic. The drilling was tricky, he adds, since there were no accurate maps of the mine, the rock is hard, the holes were deep, and the drilling paths were curved, not straight.
A pivotal moment arrived when Geotec and two other drilling companies each landed a 5½-in.-dia hole on target. The trapped miners banged on the drill bit. They were able to attach to one of the drill bits a note bearing the message that all 33 miners were alive and together in the spot. Soon, communication lines and life-sustaining supplies, food, clothing and air flowed down through the three 5½-in.-dia lifelines, while the Chilean government looked for ways to free the trapped men.
Twenty-five-year-old Igor Proestakis, field engineer for Drillers Supply International’s office in Antofagasta, Chile, which was supplying drill bits, pipe and other supplies to many of the drillers on-site, suggested widening one of the 5½-in. pilot shafts so that the miners could be lifted through it to safety.
Codelco selected Geotec’s pilot shaft as the one to enlarge. Drillers Supply called drill-bit manufacturer Center Rock Inc., Berlin, Pa., for special hard-rock bits that Geotec could use to widen the shaft—first to 12 in. dia, then to 28 in. dia—to accommodate the capsule.
In addition to supplying drill bits for the rescue effort, Center Rock owners Brandon and Julie Fisher and one of the company’s technical experts flew from the U.S. to the rescue site in Chile to lend their expertise. To help Stefanic’s team enlarge the vital rescue hole, Geotec’s U.S. affiliate Layne Christensen Co., Mission Woods, Kan., flew in two of its drillers, who possess extensive experience at boring large-diameter holes in hard rock, and two Spanish-speaking drill hands from its U.S. operation.
“Drilling large-diameter holes takes a different set of skills than drilling smaller-diameter shafts. It’s not as simple as just drilling the same hole with a larger bit,” says David Singleton, president of Layne Christensen’s water-resources division.
The drillers that Layne Christensen sent to join Stefanic’s team had been drilling large-diameter water wells in Afghanistan for the U.S. military.
Ultimately, the skill of Stefanic’s drill crew and the teamwork between Geotec, Layne Christensen, Drillers Supply and Center Rock opened the 2,040-ft-long, 28-in.-dia shaft that enabled what is believed to be the deepest-ever rescue of miners trapped underground. The effort was a huge team effort, led by Stafanic.
And they did it more than two months faster than experts originally estimated. The miners all were free by Oct. 13, not Christmas Day, as expected.
