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dip throw

The component of the slip measured parallel with the dip of the strata.
Fay

dip valley

A valley trending in the direction of the general dip of the rock layers
of a region.

dip workings

a. The workings on the lower side of the level or gate road in an inclined
seam. Dip workings may present water problems and require pumping. Also
called deep workings. Nelson
b. Underhand excavations in which miner works downward and lifts spoil to
removal point. Not self-draining. Pryor, 3

dipyramid

A closed form consisting of orthorhombic, trigonal, tetragonal, or
hexagonal positive and negative pyramids. Syn:bipyramid
CF:bipyramid; pyramid.

dipyre

A variety of scapolite having marialite:meionite between 3:1 and 3:2.
Syn:mizzonite; dipyrite.

dipyrite

See:dipyre; pyrrhotite.

direct-acting controller

One in which an increasing measured value in the input signal produces an
increasing controller output, and vice versa. Pryor, 3

direct-acting haulage

See:direct-rope haulage

direct-arc furnace

One in which an arc is struck between an electrode and the material
charged into the furnace. Pryor, 3

direct attack

A method of effecting extinction of mine fires using water or the effluent
of chemical fire extinguishers. When a mine fire is readily accessible to
the firefighting personnel, extinction of it may be achieved by direct
application of some substance that will cool down the hot mass below its
ignition temperature, or, in the case of oils, will arrest the
volatilization process by sealing or emulsifying the oil surface.
Mason

direct firing

a. The combustion of coal effected by burning directly on a grate.
Fay
b. A method of firing wherein the products of combustion come in contact
with the ware. ACSB, 2

direct flushing

Flushing in which the water rises along the rod on its outer side; i.e.,
between the walls of the borehole and the rod, and with such a velocity
that the broken rock fragments are carried up by this water current.
Stoces

direct haulage

The system in which an engine with a single drum and rope draws loaded
trucks up an incline. The empties run downhill dragging the rope after
them. CTD

direct initiation

The placing of the detonator in the last cartridge to be inserted in the
shothole with the active end of the detonator pointing inward. This
position tends to minimize the risk of gas ignition.
See also:inverse initiation

direction

a. Angle to the right (clockwise) from an arbitrary zero direction. Used
chiefly in triangulation. Seelye, 2
b. See:trend

directional drilling

a. The art of drilling a borehole wherein the course of the hole is
planned before drilling. Such holes are usually drilled with rotary
equipment and are useful in drilling divergent tests from one location,
tests that otherwise might be inaccessible, as controls for fire and wild
wells, etc. AGI
b. Drilling in which the course of a borehole is controlled by deflection
wedges or other means. The technique of directional drilling is used (1)
to deflect a deviated borehole back onto course and (2) to deflect a
borehole off course, either to bypass an obstruction in the hole or to
take a second core. Syn:slant drilling

directional solidification

The solidification of molten metal in a casting in such a manner that feed
metal is always available for the portion just solidifying. ASM, 1

directional work

See:directional drilling

direction-finding methods

Electromagnetic exploration methods in which one determines the direction
of the magnetic field associated with the currents. Schieferdecker

direction indicator

Any one of a number of geophysical devices used to determine the deviation
of a borehole from vertical. AGI

direction of dip

See:line of dip