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downdip

Parallel to or in general direction of the dip of a bed, rock stratum, or
vein. Long

downdraft

A downward current of air or other gas (as in a mine shaft, kiln, or
carburetor). Syn:downcast

downdrift

In a mine drift, the direction of predominant water movement.

downhole

a. A borehole drilled at any angle inclined downward in a direction below
the horizon.
b. adj. In a borehole; e.g., downhole equipment.--adv. Deeper; e.g., to
perforate downhole. AGI

downline

A line of detonating cord or plastic tubing in a blast hole that transmits
the detonation from the trunkline or surface delay system down the hole to
the primer.

downslope

The land surface between the projected outcrop of the lowest coalbed being
mined along each highwall and a valley floor.

downspouts

Lanc. Pipes fixed down the side of a shaft for conducting water from one
level or sump to another.

downstream face

The dry side of a dam. Nichols, 1

down-the-hole drill

A percussive or hammer drill in which the bit-driven mechanism is located
immediately behind the drill bit and is small enough in diameter to permit
it to enter and follow the bit down into the hole drilled.

down-the-hole extensometer

A device used to measure differential strains in a drill hole.

downthrow

a. The downthrown side of a fault. AGI
b. The amount of downward vertical displacement of a fault. CF:upthrow;
heave. AGI

downthrow fault

A fault that displaces the strata downward relative to the workings
approaching it. It would be an upthrow fault to workings on the opposite
side.

downthrow side

The lower side of a fault.

Downtonian

Uppermost Silurian or lowermost Devonian. AGI

downward continuation

a. Interpretation method in which the values of a component of the
magnetic field at lower levels are computed from the values at the
surface. Schieferdecker
b. The process of determining, from values measured at one level, the
value of a potential (e.g., gravitational) field at a lower level.
AGI

downward course

In mining, the course of the vein from the surface downward. Also called
course downward.

downward enrichment

See:supergene enrichment

downward percolation

See:sand leaching

Dow process

A process for the production of magnesium by electrolysis of molten
magnesium chloride. ASM, 1

dowsing

The practice of locating ground water, mineral deposits, or other objects
by means of a divining rod or a pendulum. A dowser may claim also to be
able to diagnose diseases, determine the sex of unborn babies, etc.
Syn:dousing; water witching. CF:rhabdomancy

dowsing rod

See:divining rod