a. The part of a beam or girder that actually rests on the supports.
CTD
b. Undercutting the coal face by holing. Nelson
c. The horizontal angle between the meridian (true or magnetic) and any
specified direction. The angle is measured from either the north or the
south point, as may be required to give a reading of less than 90 degrees
, and the proper quadrant is designated by the letter N or S, preceding
the angle, and the letter E or W, following it; as, N. 80 degrees E.
CF:azimuth
d. The points of support of a beam, shaft, or axle, i.e., bearing points.
e. The direction of a mine drivage usually given in terms of the
horizontal angle turned off a datum direction, such as the true north and
south line. Nelson
f. In Texas land surveys, a reference point to identify a land corner or a
point on a survey line. Seelye, 2
g. A part in which a shaft or pivot revolves. Nichols, 1
h. See:ball bearing
A bed that contains, or is likely to contain, ore minerals; one that is
productive as opposed to dead or barren. Arkell
a. The load-per-unit area that the soil or solid rock can support without
excessive yield. See also:foundation investigation
b. See also:ultimate bearing capacity
A door so placed as to direct and regulate the amount of air current
necessary for the proper ventilation of a district of a mine.
See also:separation door
The depth of an undercut, or holing, from the face of the coal to the end
of the undercut. Fay
Boreholes tending to meet in the body of the rock; intended to unkey the
face when charged and fired. Stauffer
A plate of the thickness and area required to distribute a given load,
such as a plate under a beam flange resting on a wall. If the plate is 2
in (5.1 cm) or more in thickness, it is called a slab. Crispin
The load on a bearing surface divided by the area upon which it rests.
Hammond
In a mine shaft, a specially substantial set of timbers used at intervals
to support the linings and ordinary bearers. They are tied into the
surrounding rock to give extra strength.
A stake set on a line to indicate the horizontal direction an inclined
borehole is to be drilled. Long
The earth formation that has been selected as the most suitable to support
a given load. Hammond
The maximum bearing load at failure divided by the effective bearing area.
In a pinned or riveted joint, the effective area is calculated as the
product of the diameter of the hole and the thickness of the bearing
member. ASM, 1
A monoclinic mineral, Be2 (AsO4 )(OH).4H2 O .
Eng. Soft, bluish earth. Used by well sinkers in Cambridgeshire and
Huntingdonshire. See also:caballa ball
A laborer who shovels or dumps asbestos fibers and sprays them with water
to prepare them for the beating process that reduces fibers to pulp for
making asbestos paper. DOT
Mill used for impact crushing of easily broken minerals. An armature
carrying swinging hammers, plates, or disks hits the falling stream of
rock, dashing particles against one another and against the casing of the
mill. See:hammermill
A trigonal mineral, Pb(Cu,Fe,Al)3 (SO4 )2 (OH) (sub
6) ; canary yellow; in minute plates; in Beaver County, UT.
In the "Becke test" a bright line, visible under a microscope under plane
polarized light, that separates substances of different indices of
refraction.
a. A brown resin, occurring with amber. English
b. A brown variety of retinite having a very high oxygen content (20% to
23%).
In polarized-light microscopy, a method or test for determining relative
indices of refraction between two adjacent mineral grains or between a
mineral grain and its host medium; e.g., Canada balsam, Lakeside cement,
an epoxy resin, or an immersion oil of known index of refraction. On
defocusing by increasing the working distance between the microscope stage
and the objective lens, the Becke line moves toward the higher index of
refraction. CF:van der Kolk method
An overhead monorail system. See also:monorail