Schramm, Inc. is a manufacturer of drilling equipment and truck mounted drilling rigs headquartered in Chester County, Pennsylvania. The company was founded in 1900 by Chris Schramm.
Rescuing trapped miners
In 2010, Schramm, Inc. assisted in the rescue of 33 miners trapped for 69 days as a result of the Copiapó mining accident in Chile. The company built both drilling rigs that were key in saving the miners. The Schramm T685 WS truck mounted drill bored a 5.5 inches (14 cm) hole that, on 22 August 2010, was the first to break through to the 33 trapped men, confirming they had survived the accident.[1] The company also manufactured the T130XD air core drilling rig owned by Geotec S.A., a Chilean-American joint venture drilling company. The T130 heavy drill was chosen by the general contractor for Plan B, Chilean firm Drillers Supply S.A., to widen one of the three 5.5 inches (14 cm) wide and 700 metres (2,300 ft) deep boreholes that were already used to keep the miners supplied using palomas. The T130 rig, in a three-way international race, was the first to open an escape shaft to the men.[2][3][4]
Plan B
Plan B involved a Schramm Inc. T130XD air core drill owned by Geotec S.A. (a Chilean-American joint venture drilling company) that was chosen by Drillers Supply SA (the general contractor of Plan B) to widen one of the three 5.5 inches (14 cm) boreholes that were already keeping the miners supplied with palomas. Internationally, the drills are used to drill top holes for the oil and gas industry and for mineral exploration and water wells This system employed Chilean Drillers Supply SA (DSI) personnel, Mijali Proestakis G.M. and Partner, Igor Proestakis Tech Mgr and Greg Hall C.E.O. (who joined his team on site for the last eight days of drilling) and their 7" drill pipe air core drill, a team of American drillers from Layne Christensen Co. and specialized Down-The-Hole drilling hammers from Center Rock, Inc., of Berlin, Pennsylvania. Center Rock's president and personnel from DSI Chile were present on site for the 33 days of drilling. While the Schramm rig, built by privately held Schramm, Inc. of West Chester, Pennsylvania, was already on the ground in Chile at the time of the mine collapse, additional drilling equipment was flown from the United States to Chile by United Parcel Service. The percussion-technology hammer drill could drill at more than 40 metres (130 ft) a day by using four hammers instead of one.[2][3][4]
The Schramm T-130 was directed to bore toward the workshop, a space that was accessible by the miners. The T-130 became operational on 5 September and worked in three stages. First, it needed to enlarge the 5.5 inches (14 cm) hole to a 12 inches (30 cm) hole. It then needed to drill the 12 inches (30 cm) hole into a 28 inches (71 cm) diameter hole. “If we tried to drill from a 5.5 inches (14 cm) hole to a 28 inches (71 cm) hole, the torque would be too high and it would ... put the drill bits under too much pressure,” said Schramm, Inc. Latin American Regional Manager, Claudio Soto. However by reusing the same hole, there was still added pressure on the drill. Delays occurred because of issues with the neck of the drills caused by the angle of the drilling. Rescuers couldn’t drill vertically since that would require placing the heavy rig on the unstable ground where the cave in had happened. And the rescuers also had to avoid drilling into the production tunnels that wind above the shelter. Soto added, during the rescue, “It’s a difficult hole. It’s curved and deep. The hard rock has proven to be abrasive and has worn out the steel of the drill.”
The fine rock debris, known as cuttings, fell down the pilot hole; an estimated 500 kilograms (1,100 lb) of rocks fell down every hour. Working in shifts 24 hours a day, the miners had to keep the passage clear with the industrial-sized battery-powered sweepers, shovels and wheel barrows trapped in the mine with them.[6] The miners had to remove on their own a total mass of drilling cuttings estimated at up to 700 metric tons (770 short tons), considering a borehole diameter of 70 centimetres (28 in), with a depth of 688 metres (2,257 ft) and a rock density of 2.7 tonnes per cubic metre.[7]
Its first delay was caused by it hitting a metal bar in an old working and wrecking.[8] The wrecked drill bit was retrieved by sending down a steel tube called a "spider", whose end was cut into 8 long teeth. When the spider reached the obstruction, its 8 teeth went down around the drill bit, and on further pressure bent in below the drill bit, holding it, and it was hauled to the surface. The second delay was caused by the replacement drill bit wearing out. As the drill drilled down, the spoil fell down the pilot hole and the trapped miners had to clear it away, using a front loader, fueled with diesel sent down one of the supply holes.
Schramm Inc.|
Drilling Results
| Plan A, Strata 950 (7001850000000000000♠85%) |
| Plan B, Schramm T130 (7002100000000000000♠100%) |
| Plan C, RIG-421 (7001620000000000000♠62%) |
|
Drilling results
The widened shaft of Plan B's Schramm T130XD reached the trapped miners at 08:05 CLDT on 9 October after a 10-hour stoppage to change the drill-bit.[9] By 8 October, the Plan A Strata 950's pilot hole had reached 598 metres (1,962 ft) deep (7001850000000000000♠85% - it had not yet started its widened shaft). Plan C's RIG-421, the only machine at the site which drills a shaft wide enough immediately, reached 372 metres (1,220 ft) (7001620000000000000♠62%).[10]
As illustrated in the graphic to the right, it was the Schramm T-130, Plan B, that reached the miners on Oct. 9. The rescue operation was an international effort. The rescue of the miners involved not only technology, but the cooperation and resources of companies and individuals from around the world, including Latin America, South Africa, Australia, the United States and Canada. NASA specialists helped develop a sophisticated health agenda. Canada brought in their “Plan C” drill. An Austrian system of cranes and pulleys designed for the rescue capsule eventually pulled the miners to the surface. But overall, it was widely a Chilean-led team and effort. As one NASA specialist said while visiting early on in the rescue: “The Chileans are basically writing the book.”
References
- ↑ Chesco company proud to help with Chilean miner rescue, The Mercury, Pennsylvania (US), Brian McCullough, 14 October 2010
- 1 2 "Center Rock Drill Breaks Through to Trapped Chilean Miners". Cygnus. For Construction Pros. 11 October 2010. Retrieved 13 October 2010.
- 1 2 Schramm Airdrill T130XD Rig Specifications PDF, Schramm Inc.
- 1 2 'Plan B' rises to the top for miners, Houston Chronicle (US), Zain Shauk, 13 October 2010
- ↑ Prengaman, Peter (29 August 2010). "Chile miners must move tons of rocks in own rescue". Yahoo! News. Associated Press. Retrieved 13 October 2010.
- ↑ Franklin, Jonathan (26 August 2010). "Trapped Chilean miners face long shifts to keep their refuge clear of debris". London: The Guardian. Retrieved 27 August 2010.
- ↑ Channel 4 British TV program Buried Alive: The Chilean Mine Rescue, 8 pm to 9 pm, Wednesday 27 October 2010
- ↑ La perforadora llegó al refugio donde se encuentran los mineros, La Nación On-Line, 9 October 2010.
- ↑ "Estado del operativo de rescate". Ministerio de Minería. Gobierno de Chile. 8 October 2010.
External links