A tubular well-boring bit, having a valve at the bottom, and a screw for
forcing the earth upward. Also spelled mizer. Standard, 2; Fay
An explosive charge in a drill hole that has partly or completely failed
to explode as planned. Causes include unskilled charging; defective
explosive, detonator, or fuse; broken electric circuit or--most
dangerous--cutting off of part or all of the charge through lateral rock
movement as other holes in the vicinity are fired. Stringent safety
precautions cover procedure in minimizing these risks and in dealing with
known or suspected misfires. A smoldering fuse may delay explosion,
causing a hangfire, so return to workings after a suspected failure is
necessary. Another main cause of accident is drilling into or dangerously
near a socket--an apparently empty drill hole. See also:missed hole;
hangfire. Pryor, 3
See:missed hole
See:arsenopyrite
a. In mineral processing, material, particularly screen products and
tailings, that has been reported in the wrong section. Pryor, 3
b. Material wrongly included in the products of a sizing or density
separation; i.e., material that has been included in the lower size or
specific gravity product but which itself has a size or specific gravity
above that of the cut point, or vice versa. Its weight may be expressed as
a percentage of the product or of the feed. Also called tramps
(undesirable usage). BS, 5
c. In sizing and screening, undersize contained in the overflow, or
oversize contained in the underflow. BS, 5
d. In cleaning, material of specific gravity lower than the separation
density that has been included in the high density product, or material of
specific gravity higher than the separation density that has been included
in the low density product. BS, 5
A drill hole charged with explosives, in which all or part of the
explosive has failed to detonate. Syn:misfire; misfire hole.
Fraenkel
A round in which all or part of the explosive has failed to detonate.
Fraenkel
A period of the Paleozoic era (after the Devonian and before the
Pennsylvanian), thought to have covered the span of time between 345 and
320 million years ago; also, the corresponding system of rocks. It is
named after the Mississippi River valley, in which there are good
exposures of rocks of this age. It is the approximate equivalent of the
Lower Carboniferous of European usage. AGI
An old term for copiapite and related minerals.
Mitchell system for underhand quarrying of panel cores
See:bevel gear
A monoclinic mineral, Ca2 Fe3 (PO4 )3 O (sub
2) .3H2 O ; forms red crystals, green stains in granite pegmatites.
A single-tube, drive-type, soil-sampling barrel esp. adapted to sampling
deposits of plastic clay where a minimum 5-in (12.7-cm) diameter sample is
required. A loop or snare of piano wire is inserted in a groove inside the
cutting shoe with the free end of the wire extending through a slot on the
side of the sampler to the surface. When pulled, the wire cuts the sample
off at the bottom of the cutting shoe. Long
A tetragonal mineral, K2 CuCl4 .2H2 O ; greenish
blue.
See:solid solution
Drill diamonds ranging from 23 to 80 per carat in size. Long
A modification of the basic Bessemer process in which all the nitrogen is
removed from the blast, it being made up of a mixture of oxygen and carbon
dioxide or oxygen and superheated steam. The oxygen and superheated steam
blast is claimed to be the more efficient, the final nitrogen content of
the metal being brought to a mean level of 0.0028%. Osborne
A product obtained by mixing, or blending, either portland, natural, or
pozzolana cement with one another or with other inert substances.
Zern
See:solid solution
Dust prepared for testing in a mine by mixing coal dust and inert dust in
predetermined proportions. The mixture may also contain water, and
different sizes of coal dust may be mixed to produce some desired
intermediate size. Rice, 2
Occurs when both combustible gases and coal dust are present below their
lower limits, but in combination produce sufficient heat of combustion to
propagate an explosion. Sinclair, 1