A down-the-hole drill, usually called DTH by most professionals, is basically a jackhammer screwed on the bottom of a drill string. The fast hammer action breaks hard rock into small cuttings and dust that are evacuated by a fluid (air, water or drilling mud). The DTH hammer is one of the fastest ways to drill hard rock. The system is thought to have been invented independently by Stenuick. Origin of the nameDTH is short for “down-the-hole”. Since the DTH method was originally developed to drill large-diameter holes downwards in surface-drilling applications, its name originated from the fact that the percussion mechanis. .
In DTH drilling, the percussion mechanism – commonly called the hammer – is located directly above the drill bit. The drill pipes transmit the necessary feed force and rotation to the hammer and the bit, along with the flui.
[pdf] The Aban Pearl was designed by and was built in 1977 by Far East Levingston Shipbuilding (now part of the ) at the Levingston Singapore shipyard. The Aban Pearl could operate at. .
In 1977–1996, she was named Transocean Seeker, in 1996 Treasure Seeker and in 1996–2000 Transocean Discoverer. All this time she was owned by . In 2000–2007, she was named Bulford Dolphin an. .
In 2006, while contracted by the Nigerian oil company Peak Petroleum, the rig was attacked near Nigeria by Nigerian militants and eight of the personnel on the rig were kidnapped. They were released unharmed after two da.
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