When 33 miners were rescued from the San José copper mine, the story not only captured the imagination of the world’s media, but also illustrated the expertise and equipment that the mining industry can bring to bear.
The miners became trapped 700m underground on August 5, following the collapse of the main access decline (at a depth of 400-500m) and, subsequently, the ventilation shaft.
San Esteban Primera faces financial collapse because, in addition to its existing debts, the mine has been closed permanently, by order of Chile’s president, Sebastian Piñera. An audit of the company is currently being conducted to decide how best to pay its creditors.
The rescue attempt was made, and resourced, independently of San Esteban Primera, and included contributions from the state-run mining company, Codelco, and mining and equipment companies from around the world.
These firms incurred an estimated US$20 million in costs during the rescue effort, the majority of which went towards the machines used for drilling, as well as the communications equipment required due to the mine’s remote location, and the number of man hours spent on the project.
Initial contact
Following the mine collapse, nine drill rigs, including four Schramm T685WS models, were deployed by exploration firms. These included Adviser Drilling, Geotec, Boyles Bros, Major Drilling and Terraservice.
GeoAtacama Consultores was on site to perform borehole-orientation surveys, while Maptek’s Vulcan software was used to locate the boreholes and create a 3D map of the mine’s underground workings.
A number of down-hole survey instruments were used to help measure borehole inclination, including equipment from Stockholm Precision Tools and Devico. This team worked alongside staff from BHP Billiton’s Escondida operation, Codelco and the Collahuasi mine (owned by Xstrata and Anglo American), among others, to establish whether the miners had survived.
Despite several failed drilling attempts and a second collapse on August 7, which hampered the rescue by blocking access to the lower parts of the mine, the rescuers made contact with the miners 17 days later, on August 22, in the underground refuge chamber where they had taken shelter.
A Mincon reverse-circulation hammer was used to create the borehole, measuring 14cm in diameter by 701m deep. When the hammer was retrieved, a note was attached to the drill bit, explaining that the miners were alive and awaiting rescue.
A second hole was made to allow rations and communication lines to be established with the miners during the estimated three to four-month period it would take to create an escape route.
Three drilling methods
Three separate rescue plans were formulated and conducted simultaneously in order to reach the miners as quickly as possible. These involved creating three boreholes using different techniques. Whichever hole broke through and was secured first would be used to winch the miners back to the surface.
n Plan A: this hole was excavated using a Strata 950 raise-bore machine, borrowed from Codelco’s Andina mine. The machine, which is one of only six such drills in existence, was designed in Kalgoorlie by Australia’s RUC Cementation.
n Plan B: this used a Schramm T130 drill, and the 13cm pilot hole was aimed at the mine’s machine workshop, a few hundred metres from the refuge.
n Plan C: using an oil-industry drill rig, this was the fastest option on paper, but drilling did not begin until September 20. The target depth of the hole was 597m. To protect against poor ground conditions at 380-430m, Schlumberger planned to line the hole with steel pipe.
Successful hole
Geotec Boyles Bros was the appointed operator for Plan B. The company arrived on site on September 3, bringing the Schramm T130XD rig (now nicknamed the Miracle) from northern Chile.
Center Rock, a Berlin-based manufacturer of drilling tools, fabricated special drilling tools and bits to allow the rig to enlarge the pilot borehole from 13-30cm in diameter, and a second set to allow enlargement from 30-71cm.
Brandon Fisher, president of Center Rock, personally accompanied the drilling tools to the mine site, and was in telephone and e-mail communication with Greg Hillier, Schramm’s product manager, on a daily basis.
Working in conjunction with Jim Stefanic, Geotec’s mine-site operations manager, Schramm dispatched field-service engineer Jeff Roten to the site to ensure the T130XD rig operated round the clock at its fullest potential.
Through Schramm’s Chilean customer service centre, Exploration Drill Masters (EDM), a large quantity of spare parts were moved from Santiago to the rescue site, where EDM personnel were also available to help with any mechanical equipment issues.
On September 5, drilling began to enlarge the original 13cm borehole to 30cm in diameter. At a depth of 268m, the drill bit was severely damaged after striking a steel roof bolt. This caused a four-hour delay while the crew fished for the broken bit (and roof bolt) with makeshift tools, designed and modified on site. The borehole broke through at a depth of 701m on September 18.
Drilling to enlarge the hole from 30-71cm diameter began on September 19. On the morning of the 21st, the crew reported that they had completed 50m of drilling. On the 23rd, the drill had reached 110m, and on September 28, the Schramm T130XD successfully passed the area where it had previously encountered the steel roof bolt.
On October 4, given the accelerated rate of penetration, President Piñera announced that he hoped the miners would be freed by October 15. At this point, the drill had reached 467m, and on October 9, at 8:03am (local time), the drill successfully broke through into the miners’ workshop.
The rescue
After a video inspection of the shaft to check rock, the rescuers decided that only the first 96m of the borehole needed casing.
Sixteen steel tubes, each measuring 6m in length and 60cm in diameter, were welded together and installed in the shaft on October 11. This was designed to prevent loose rocks and soil from jamming the rescue capsule, which would be winched down to collect the miners.
The Chilean army fabricated the Phoenix rescue capsule especially for the mission. Measuring 3m long by 53cm in diameter, the capsule was equipped with a communications system, oxygen and a harness, allowing the passenger to open a door and lower them self back down the shaft in the event that the capsule got stuck.
After a number of unmanned test runs, the rescue operation began just before midnight on October 12. Over the next 24 hours, all 33 miners were winched safely to the surface, from where they were taken directly to hospital for medical checks.
The miners became trapped 700m underground on August 5, following the collapse of the main access decline (at a depth of 400-500m) and, subsequently, the ventilation shaft.
San Esteban Primera faces financial collapse because, in addition to its existing debts, the mine has been closed permanently, by order of Chile’s president, Sebastian Piñera. An audit of the company is currently being conducted to decide how best to pay its creditors.
The rescue attempt was made, and resourced, independently of San Esteban Primera, and included contributions from the state-run mining company, Codelco, and mining and equipment companies from around the world.
These firms incurred an estimated US$20 million in costs during the rescue effort, the majority of which went towards the machines used for drilling, as well as the communications equipment required due to the mine’s remote location, and the number of man hours spent on the project.
Initial contact
Following the mine collapse, nine drill rigs, including four Schramm T685WS models, were deployed by exploration firms. These included Adviser Drilling, Geotec, Boyles Bros, Major Drilling and Terraservice.
GeoAtacama Consultores was on site to perform borehole-orientation surveys, while Maptek’s Vulcan software was used to locate the boreholes and create a 3D map of the mine’s underground workings.
A number of down-hole survey instruments were used to help measure borehole inclination, including equipment from Stockholm Precision Tools and Devico. This team worked alongside staff from BHP Billiton’s Escondida operation, Codelco and the Collahuasi mine (owned by Xstrata and Anglo American), among others, to establish whether the miners had survived.
Despite several failed drilling attempts and a second collapse on August 7, which hampered the rescue by blocking access to the lower parts of the mine, the rescuers made contact with the miners 17 days later, on August 22, in the underground refuge chamber where they had taken shelter.
A Mincon reverse-circulation hammer was used to create the borehole, measuring 14cm in diameter by 701m deep. When the hammer was retrieved, a note was attached to the drill bit, explaining that the miners were alive and awaiting rescue.
A second hole was made to allow rations and communication lines to be established with the miners during the estimated three to four-month period it would take to create an escape route.
Three drilling methods
Three separate rescue plans were formulated and conducted simultaneously in order to reach the miners as quickly as possible. These involved creating three boreholes using different techniques. Whichever hole broke through and was secured first would be used to winch the miners back to the surface.
n Plan A: this hole was excavated using a Strata 950 raise-bore machine, borrowed from Codelco’s Andina mine. The machine, which is one of only six such drills in existence, was designed in Kalgoorlie by Australia’s RUC Cementation.
n Plan B: this used a Schramm T130 drill, and the 13cm pilot hole was aimed at the mine’s machine workshop, a few hundred metres from the refuge.
n Plan C: using an oil-industry drill rig, this was the fastest option on paper, but drilling did not begin until September 20. The target depth of the hole was 597m. To protect against poor ground conditions at 380-430m, Schlumberger planned to line the hole with steel pipe.
Successful hole
Geotec Boyles Bros was the appointed operator for Plan B. The company arrived on site on September 3, bringing the Schramm T130XD rig (now nicknamed the Miracle) from northern Chile.
Center Rock, a Berlin-based manufacturer of drilling tools, fabricated special drilling tools and bits to allow the rig to enlarge the pilot borehole from 13-30cm in diameter, and a second set to allow enlargement from 30-71cm.
Brandon Fisher, president of Center Rock, personally accompanied the drilling tools to the mine site, and was in telephone and e-mail communication with Greg Hillier, Schramm’s product manager, on a daily basis.
Working in conjunction with Jim Stefanic, Geotec’s mine-site operations manager, Schramm dispatched field-service engineer Jeff Roten to the site to ensure the T130XD rig operated round the clock at its fullest potential.
Through Schramm’s Chilean customer service centre, Exploration Drill Masters (EDM), a large quantity of spare parts were moved from Santiago to the rescue site, where EDM personnel were also available to help with any mechanical equipment issues.
On September 5, drilling began to enlarge the original 13cm borehole to 30cm in diameter. At a depth of 268m, the drill bit was severely damaged after striking a steel roof bolt. This caused a four-hour delay while the crew fished for the broken bit (and roof bolt) with makeshift tools, designed and modified on site. The borehole broke through at a depth of 701m on September 18.
Drilling to enlarge the hole from 30-71cm diameter began on September 19. On the morning of the 21st, the crew reported that they had completed 50m of drilling. On the 23rd, the drill had reached 110m, and on September 28, the Schramm T130XD successfully passed the area where it had previously encountered the steel roof bolt.
On October 4, given the accelerated rate of penetration, President Piñera announced that he hoped the miners would be freed by October 15. At this point, the drill had reached 467m, and on October 9, at 8:03am (local time), the drill successfully broke through into the miners’ workshop.
The rescue
After a video inspection of the shaft to check rock, the rescuers decided that only the first 96m of the borehole needed casing.
Sixteen steel tubes, each measuring 6m in length and 60cm in diameter, were welded together and installed in the shaft on October 11. This was designed to prevent loose rocks and soil from jamming the rescue capsule, which would be winched down to collect the miners.
The Chilean army fabricated the Phoenix rescue capsule especially for the mission. Measuring 3m long by 53cm in diameter, the capsule was equipped with a communications system, oxygen and a harness, allowing the passenger to open a door and lower them self back down the shaft in the event that the capsule got stuck.
After a number of unmanned test runs, the rescue operation began just before midnight on October 12. Over the next 24 hours, all 33 miners were winched safely to the surface, from where they were taken directly to hospital for medical checks.