down-the-hole drilling
71Moho line — The Mantle is a part of an astronomical object. Earth s mantle is a 2,900 km thick rocky shell comprising approximately 70% of Earth s volume. It is predominantly solid and overlies the Earth s iron rich core, which occupies about 30% of Earth s… …
72Earth Sciences — ▪ 2009 Introduction Geology and Geochemistry The theme of the 33rd International Geological Congress, which was held in Norway in August 2008, was “Earth System Science: Foundation for Sustainable Development.” It was attended by nearly… …
73Antarctica — /ant ahrk ti keuh, ahr ti /, n. the continent surrounding the South Pole: almost entirely covered by an ice sheet. ab. 5,000,000 sq. mi. (12,950,000 sq. km). Also called Antarctic Continent. * * * Antarctica Introduction Antarctica Background:… …
74mining — /muy ning/, n. 1. the act, process, or industry of extracting ores, coal, etc., from mines. 2. the laying of explosive mines. [1250 1300; ME: undermining (walls in an attack); see MINE2, ING1] * * * I Excavation of materials from the Earth s… …
75Well logging — Gamma ray logging Spontaneous potential logging Resistivity logging Density logging Sonic logging Caliper logging Mud logging LWD/MWD v · …
76tunnels and underground excavations — ▪ engineering Introduction Great tunnels of the world Great tunnels of the worldhorizontal underground passageway produced by excavation or occasionally by nature s action in dissolving a soluble rock, such as limestone. A vertical opening …
77Drill bit — For the fictional character, see Drill Bit (Transformers). For the cancelled skyscraper nicknamed Drill bit, see Chicago Spire. For the types used in drilling wells, see Well drilling. From top to bottom: Spade, lip and spur (brad point), masonry …
78petroleum production — Introduction recovery of crude oil and, often, associated natural gas from the Earth. petroleum is a naturally occurring hydrocarbon material that is believed to have formed in deep sedimentary (sedimentary rock) beds from animal and …
79hand tool — any tool or implement designed for manual operation. * * * Introduction any of the implements used by craftsmen in manual operations, such as chopping, chiseling, sawing, filing, or forging. Complementary tools, often needed as auxiliaries to… …
80Deepwater Horizon oil spill — 2010 oil spill and BP oil spill redirect here. For other oil spills in 2010, see 2010 oil spill (disambiguation). For the 2006 oil spill involving BP, see Prudhoe Bay oil spill. For the drilling rig and explosion, see Deepwater Horizon… …
