A down-the-hole drill, usually called DTH by most professionals, is basically a screwed on the bottom of a . The fast hammer action breaks hard rock into small cuttings and dust that are evacuated by a fluid (air, water or ). The DTH hammer is one of the fastest ways to drill hard rock. The system is thought to have been invented independently by Stenuic.
[pdf] JK730-2 crawler mounted automatic rod exchange DTH drill rig is a hydraulic DTH drill rig. It is equipped with automatic rod changer for rod storage, changing and connecting automatically, as well as hole loc.
[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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