Definition of drift
i. An entry, generally on the slope of a hill, usually driven horizontally into a coal seam.
Synonym of: surface
ii. The deviation of a borehole from its intended direction or target.
Compare with: walk
iii. A general term, used esp. in Great Britain, for all surficial, unconsolidated rock debris transported from one place and deposited in another, and distinguished from solid bedrock; e.g., specif. for glacial deposits. Any surface movement of loose incoherent material by the wind; accumulated in a mass or piled up in heaps by the action of wind or water.
See Also: fill
iv. Apparent offset of aerial photographs with respect to the true flight line, caused by the displacement of the aircraft owing to cross winds, and by failure to orient the camera to compensate for the angle between the flight line and the direction of the aircraft's heading. The photograph edges remain parallel to the intended flight line, but the aircraft itself drifts farther and farther from that line.
Ref: AGI
v. A time variation common to nearly all sensitive gravimeters, due to slow changes occurring in the springs or mountings of the instrumental systems; this variation is corrected by repeated observations at a base station and in other ways.
Ref: AGI
vi. A horizontal opening in or near an orebody and parallel to the course of the vein or the long dimension of the orebody.
Ref: Beerman
vii. A passageway driven in the coal from the surface, usually above drainage, following the inclination of the bed.
Ref: Hudson
viii. Forest of Dean. A hard shale.
ix. To make a drift; to drive.
Ref: Webster 3rd
x. A horizontal gallery in mining and civil engineering driven from one underground working place to another and parallel to the strike of the ore. It is usually of a relatively small cross section. Larger sections are usually called tunnels.
Ref: Fraenkel
xi. A heading driven obliquely through a coal seam.
Ref: CTD
xii. A heading in a coal mine for exploration or ventilation.
Ref: CTD
xiii. An inclined haulage road to the surface.
Ref: CTD
xiv. In oil well surveying, the angle from a drill hole to the vertical.
See Also: inclination
xv. A flat piece of steel of tapering width used to remove taper shank drills and other tools from their holders.
Ref: ASM, 1
xvi. A tapered rod used to force mismated holes in line for riveting or bolting. Sometimes called a driftpin.
Ref: ASM, 1
xvii. A gradual change in a reference that is supposed to remain constant. An instrument such as a gravimeter may show drift as a result of elastic aging, long-term creep, hysteresis, or other factors.
Ref: AGI
xviii. A general term applied to all rock material (clay, silt, sand, gravel, boulders) transported by a glacier and deposited directly by or from the ice, or by running water emanating from a glacier. Drift includes unstratified material (till) that forms moraines, and stratified deposits that form outwash plains, eskers, kames, varves, glaciofluvial sediments, etc. The term is generally applied to Pleistocene glacial deposits in areas (as large parts of North America and Europe) that no longer contain glaciers. The term drift was introduced by Murchison in 1839 for material, then called diluvium, that he regarded as having drifted in marine currents and accumulated under the sea in comparatively recent times; this material is now known to be a product of glacial activity.
Compare with: glacial drift
xix. One of the wide, slower movements of surface oceanic circulation under the influence of, and subject to diversion or reversal by, prevailing winds; e.g., the easterly drift of the North Pacific. The speed of an ocean current or ice floe, usually given in nautical miles per day or in knots. Sometimes used as a short form of littoral drift.
Synonym of: drift current, ocean current
See: current
xx. In South Africa, a ford in a river. The term is used in many parts of Africa to indicate a ford or a sudden dip in a road over which water may flow at times.
Synonym of: drif
Synonym of: surface
ii. The deviation of a borehole from its intended direction or target.
Compare with: walk
iii. A general term, used esp. in Great Britain, for all surficial, unconsolidated rock debris transported from one place and deposited in another, and distinguished from solid bedrock; e.g., specif. for glacial deposits. Any surface movement of loose incoherent material by the wind; accumulated in a mass or piled up in heaps by the action of wind or water.
See Also: fill
iv. Apparent offset of aerial photographs with respect to the true flight line, caused by the displacement of the aircraft owing to cross winds, and by failure to orient the camera to compensate for the angle between the flight line and the direction of the aircraft's heading. The photograph edges remain parallel to the intended flight line, but the aircraft itself drifts farther and farther from that line.
Ref: AGI
v. A time variation common to nearly all sensitive gravimeters, due to slow changes occurring in the springs or mountings of the instrumental systems; this variation is corrected by repeated observations at a base station and in other ways.
Ref: AGI
vi. A horizontal opening in or near an orebody and parallel to the course of the vein or the long dimension of the orebody.
Ref: Beerman
vii. A passageway driven in the coal from the surface, usually above drainage, following the inclination of the bed.
Ref: Hudson
viii. Forest of Dean. A hard shale.
ix. To make a drift; to drive.
Ref: Webster 3rd
x. A horizontal gallery in mining and civil engineering driven from one underground working place to another and parallel to the strike of the ore. It is usually of a relatively small cross section. Larger sections are usually called tunnels.
Ref: Fraenkel
xi. A heading driven obliquely through a coal seam.
Ref: CTD
xii. A heading in a coal mine for exploration or ventilation.
Ref: CTD
xiii. An inclined haulage road to the surface.
Ref: CTD
xiv. In oil well surveying, the angle from a drill hole to the vertical.
See Also: inclination
xv. A flat piece of steel of tapering width used to remove taper shank drills and other tools from their holders.
Ref: ASM, 1
xvi. A tapered rod used to force mismated holes in line for riveting or bolting. Sometimes called a driftpin.
Ref: ASM, 1
xvii. A gradual change in a reference that is supposed to remain constant. An instrument such as a gravimeter may show drift as a result of elastic aging, long-term creep, hysteresis, or other factors.
Ref: AGI
xviii. A general term applied to all rock material (clay, silt, sand, gravel, boulders) transported by a glacier and deposited directly by or from the ice, or by running water emanating from a glacier. Drift includes unstratified material (till) that forms moraines, and stratified deposits that form outwash plains, eskers, kames, varves, glaciofluvial sediments, etc. The term is generally applied to Pleistocene glacial deposits in areas (as large parts of North America and Europe) that no longer contain glaciers. The term drift was introduced by Murchison in 1839 for material, then called diluvium, that he regarded as having drifted in marine currents and accumulated under the sea in comparatively recent times; this material is now known to be a product of glacial activity.
Compare with: glacial drift
xix. One of the wide, slower movements of surface oceanic circulation under the influence of, and subject to diversion or reversal by, prevailing winds; e.g., the easterly drift of the North Pacific. The speed of an ocean current or ice floe, usually given in nautical miles per day or in knots. Sometimes used as a short form of littoral drift.
Synonym of: drift current, ocean current
See: current
xx. In South Africa, a ford in a river. The term is used in many parts of Africa to indicate a ford or a sudden dip in a road over which water may flow at times.
Synonym of: drif
