The main shaft of the 125-year-old San Jose Mine near Copiapo, 500 mi. north of Santiago, Chile, collapsed on Aug. 5, 2010.
An estimated 700,000 tons of rock shifted, trapping 33 men 2,300 ft (700 m) underground. The group was able to reach a reinforced area serving as an emergency refuge in the gold and copper mine, privately owned by Compania Minera San Esteban Primera.
The majority of the trapped men are from Copiapo and range in age from Mario Gomez, who is in his early sixties and has worked in mines since he was 12, to 19-year-old Jimmy Sanchez, a new father whose baby was a month old at the time of the collapse.
A meticulously organized rescue plan to be carried out by an international cooperative effort swung into action, overseen by Codelco, the state-owned mining enterprise and the largest company in Chile.
However, it was not only due to the sterling above-ground efforts that the men returned safely. The party organized itself to help itself, led by shift supervisor Luis Urzua. According to psychologists assisting the trapped men to cope with their situation, this cohesion and direction of purpose was vital to their mental health, while also helping them to cooperate in their own interests.
Thus under the leadership of Urzua and without knowing when or even if they would be rescued, the men stretched two or three days’ supply of food for more than two weeks, limiting themselves to a cracker and minute amounts of tuna and peaches every two days. Although they were unable to run it too long because of the likelihood of contaminating their air, the miners used a bulldozer to access a pocket of water, having also drunk water from the radiators of equipment entombed with them.
Since the miners could not be reached from the surface and their whereabouts was initially unknown, boreholes were drilled in an effort of find them.
Four T685WS exploration rigs manufactured by West Chester, Pa.-based Schramm Inc. were among nine used in these attempts. The rigs concerned are owned by Chilean drillers Adviser Drilling, Geotec Boyles Bros S.A., Major Drilling S.A., and Terraservice. All four companies work in the mineral exploration industry.
Although this drilling began on Aug. 8, it was not until Aug. 22 that Terraservice’s T685WS drill reached the trapped miners. A note from the men written in red ink announcing they were well subsequently came up attached to the drill.
Three boreholes of 5.5 in. (14 cm) diameter drilled by this rig and others of the same model were used to lower food, LED lights, water and similar supplies in 5 ft. long (1.5 m) plastic containers the miners dubbed pigeons or doves. Medications were provided by this route for three miners with health problems — Gomez has silicosis, Jose Ojeda suffers from diabetes, and Jorge Galleguillos, who is one of 14 brothers and has hypertension. However, Claudio Yanez was reportedly not pleased when instead of requested cigarettes he was sent nicotine patches.
Communication with the outside world was facilitated via streaming video, a camera having been lowered to the men the day they were located.
To reach the men, a narrow shaft was bored for the escape capsule, a task made more difficult because the shaft began at an angle before plunging vertically due to the necessity of curving its path to avoid dangerous areas. The majority of the shaft passed through solid rock and in addition, once the shaft was drilled, to guard against the possibility of blockage it was necessary to close off fractured rock at its upper end. The first 165 ft. (55 m) were therefore lined and strengthened with steel casing.
Three simultaneous drilling operations were undertaken to reach the men.
Plan A involved a Strata 950 drilling rig run by Cemetation Canada Inc. South African mining company Murray & Roberts was already operating the rig in Chile and it was the first to begin boring an escape shaft. Due to the method of operation the miners had to clear away drilling debris in round-the-clock shifts and it has been estimated they moved up to 771 tons 700 t) in this fashion.
Plan C used a RIG-421 oil drilling rig. It, too, was already in Chile, but had previously only been used for oil exploration. Another Canadian company, Precision Drilling Corporation, ran the rig, brought to the mine in 40 trucks and assembled on site. While it was able to drill a shaft wide enough for the escape capsule immediately rather than having to make a borehole and enlarge it, at one point the drill size had to be reduced, causing a delay in operations.
The Plan B team succeeded in reaching the miners first, and two Pennsylvania companies played vital roles in the daunting rescue task.
One of the supply boreholes drilled by Geotec Boyles Bros S.A. on Aug. 27 became Plan B’s escape shaft. For the job, Geotec used a truck-mounted Schramm T685WS reverse circulation rig with a 750 hp onboard 500 psi air compressor. The job involved enlarging the 5.5 in. diameter tunnel to a 12-in. (30.5 cm) diameter and then to 28 in. (71 cm), using a Schramm T130XD self-propelled mobile drilling rig.
Special measures were needed in order to accomplish the task and drilling tool manufacturer Center Rock Inc., of Berlin, Pa., designed and manufactured the two drill systems involved.
“We contacted the Chilean government when we heard about the accident, quickly designed a drilling program using our equipment, and proposed it to the Mining Ministry. Fortunately they accepted our proposal and it was put into action as Plan B,” said Brandon Fisher, president of Center Rock Inc.
The two companies cooperated closely during the drilling, with Fisher in daily communication from Chile with Greg Hillier, product manager of Schramm. Richard Soppe, Center Rock’s director of construction and mining tools, also was in Chile. He and Fisher were on site for 37 days, supervising the operation and maintenance of the Schramm drill, which was fitted first with a Center Rock 5.5 in. by 12 in. (14 by 30.5 cm) DHD Hammer drill bit, changing to a 12-in. by 28-in. (30.5 by 71 cm) LP bit as work progressed on enlarging the borehole.
Schramm also worked with Jim Stefanic, Geotec’s mine site operations manager, and sent its field service engineer Jeff Roten to Chile to ensure the T130XD drill performed to its highest level in round-the-clock operations.
The 12-in. diameter borehole reached the miners on Sept. 18, after a delay due to severe damage to the drilling bit caused by a steel bolt in the mine roof at 879 ft. (268 m). In addition to repairing the bit, the crew had to remove the bolt and the broken bit, using makeshift tools created on site.
Drilling to enlarge the borehole commenced on Sept. 19. By Sept. 23, the drill was 364 ft. (110 m) down. Five days later, it had reached 987 ft. (301 m), having safely passed through the area where it had encountered the bolt. By Oct. 4, the drill had reached 1,532 ft. (467 m) and on Oct. 9, more than two months after the collapse, drilling ended at a depth of 2,041 ft. (622 m).
Finally, on Oct. 13, the rescue capsule, having passed its test runs with flying colors, began its first journey to the bottom of the rescue shaft. Painted white, red, and blue — the colors of Chile’s flag — the 13-ft. (4 m) long steel cage was the biggest of three constructed by Chilean Navy engineers. The capsules were named after the Phoenix, a legendary bird said to rise again from its own funeral pyre.
While there was always the possibility of disasters such as the capsule being trapped by rock fall in the shaft, the main concern once the men began their journey to safety was whether they could cope with the extremely confined space in the capsule. With two-way communication and a camera broadcasting from inside it, the plan was that should signs of panic appear, the speed of extraction could be increased to as much as 10 ft. (3 m) a second, but fortunately the entire operation was carried out without the need to do so.
Finally, about 10 minutes into Oct. 13, after a record 69 days underground, Florencio Avalos was the first miner rescued. He hugged his wife and son, and then embraced Chilean President Sebastian Pinera, who was closely involved in rescue efforts. Avalos’ brother Renan was the 25th to be rescued.
Mario Sepulveda emerged second. His natural ebullience endeared him to many following the saga, and he did not so much emerge from the capsule as erupt from it. After hugging his wife, President Pinera, and anyone else within reach, he presented the president with a rock signed by all the miners.
The fourth man to appear was Carlos Mamani, the only Bolivian in the group. He had emigrated from Bolivia with 10 siblings due to lack of work. Other miners brought up included Omar Reygadas, who became a great-grandfather for he fourth time while underground, Franklin Lobos, who played on Chile’s soccer team when it qualified for the 1984 Los Angeles Olympics, Richard Villarroel, an expectant father, Raul Bustos, a hydraulics engineer who had been in charge of the miners’ water supply, and Jose Henriquez, who organized a prayer group underground.
The last miner to come to the surface was shift supervisor Luis Urzua, followed by several rescuers who had descended into the mine to help the men get into the capsule. Initially it had been thought the rescue would take until Christmas to accomplish, but within 24 hours of breakthrough the seemingly impossible mission had been completed at an estimated cost of between $10 to $20 million.
About the Companies
Schramm Inc. is headquartered in West Chester, Pa. Founded in 1900, it manufactured air compressors and engine-driven machinery. The company, which now has 165 employees, was a pioneer in air flush drilling and built the first mobile drilling rigs 60 years ago. Building about 100 rigs a year, it specializes in mobile rigs, focusing on mineral, oil and gas, exploration and water wells, as well as an increasing number of mine rescues worldwide.
It was named 2010 member company of the year by the World Trade Center of Greater Philadelphia.
Center Rock Inc., was founded in 1998. The company assisted in a similar rescue in July 2002, when it helped free nine men trapped for three days in a flooded mine not far from its headquarters in Berlin, Pa. In the past five years, Center Rock has grown from 16 to more than 70 employees. CEG
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