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Deepest rescue shaft ever drilled

Deepest rescue shaft ever drilledAfter 33 days drilling, on 09.10.2010, a Schramm T130XD (Layne Christensen www.laynechristensen.com/Boyles Bros Geotec www.geotec.cl, US/Chile) top head rig completed a 66 cm-diameter x 622 m-deep hole at 82 degrees between surface and the main ramp of the San Jose mine near Copiapo in Chile to enable rescue of 33 miners trapped since a mine collapse on 05.08.2010. The miners were missing for 17 days until a small diameter hole penetrated a gallery some 20 m from their refuge chamber. They were able to tap on the drill string to alert the drillers, and subsequently send a written message to the surface. Despite the lack of creature comforts, exacerbated by heat and humidity, they were in good shape. They had survived on the small food ration stocked in the refuge chamber, and by drinking mine water. They had powered their cap lamps using a truck battery, and had exercised in the 2 km of accessible galleries around the refuge. The Schramm hole was one of three attempts to drill a rescue shaft. A Strata 950 raise borer (RUC, Australia www.ruc.com.au/fleet-raise.html) drilling at 90 degrees, and a RIG-422 oil well rig (Precision Drilling Corp, Canada www.precisiondrilling.com) at 85 degrees, were employed on two adjacent holes. The Schramm hole followed a 12.5 cm-diameter pilot hole which was far from straight, causing high bit wear and breakage. After photo-reconnaissance established the integrity of the rescue hole, the top 54 m was steel cased as a precaution against rope erosion and rock scaling. The rescue operation began on 13.10.2010 using a 54 cm-diameter winched capsule designed by NASA and the Chilean Navy. Click for tunnelbuilder Hall of Fame. 41/10.