In mechanized mining, the arm that extends between the fulcrum jack and
the swivel or angle trough or turn. Jones, 1
In Vermont, large wooden blocks covered with felt pads that are propelled
back and forth by means of a crank and pitman. Used for polishing
monumental stone.
See:Griffin mill; Huntington mill.
Small folds and faults that form in sediments shortly after they are
deposited, in igneous rocks as they solidify, and in metamorphic rocks as
they recrystallize.
äE «ý[ Â \ Z/ …DICTIONARY TERMS:peneplain A nearly horizontal surface of slight rel
[\B]peneplain[\N]
The subaerial degradation of a region approx. to base level, forming a
peneplain.
A pulley around which a wire cable runs in cutting marble. Its thickness
is less than the diameter of the wire and consequently, it can follow the
wire as the latter cuts into the stone.
See:feed rate
The penetration speed of a drill related to the size of the hole and bit,
mud pressure, speed of rotation, weight on bit, etc. From the results,
which are plotted as penetration curves, the thickness of coal and dirt
bands in the borehole can be determined with reasonable accuracy.
Nelson
Screened gravel or crushed stone aggregate, bound by bituminous grouting,
the binder being introduced after compaction of the aggregate.
Nelson
The distance a drive-type soil sampler, casing, drivepipe, pile, or
penetrometer is driven into the formation being tested by each blow
delivered by a specific-size drivehammer allowed to fall a specific
distance. Long
The actual rate of penetration of drilling tools. See also:feed rate;
drilling rate. BS, 9
a. The number of blows of a hammer of specified weight falling a given
distance required to produce a given penetration into soil of a pile,
casing, or sampling tube. Also called standard penetration resistance;
proctor penetration resistance. ASCE
b. The unit load required to maintain constant rate of penetration into
soil by a probe or instrument. ASCE
c. The unit load required to produce a specified penetration into soil at
a specified rate by a probe or instrument. For a proctor needle, the
specified penetration is 2-1/2 in (6.35 cm) and the rate is 1/2 in/s (1.27
cm/s). ASCE
The curve showing the relationship between the penetration resistance and
the water content. Also called proctor penetration curve. ASCE
The speed at which a drill can cut through rock or other material.
See also:overall drilling time
A test to determine the relative densities of noncohesive soils, sands, or
silts; e.g., the standard penetration test that determines the number of
blows required by a standard weight, when dropped from a standard height
(30 in or 76.2 cm per blow), to drive a standard sampling spoon a standard
penetration (12 in or 30.5 cm); or the dynamic penetration test, which
determines the relative densities of successive layers by recording the
penetration per blow or a specified number of blows.
See also:cone penetration test
A twin crystal in which two parts interpenetrate with each other and share
a common volume. Syn:interpenetration twin
An instrument to assess the strength of a coal seam, its relative
workability, and the influence of roof pressure. See also:sounding;
coal penetrometer. Nelson
Unproductive grit and sandstone between the Lower and Upper Coal Measures,
South Wales and Bristol, England, coalfield. Largely quarried for paving
and building. Also called pennan grit; pennant stone. Arkell
A monoclinic mineral, Mn5 Al(Si3 Al)O10 (OH)8;
chlorite group; excellent cleavage with flexible laminae; commonly
associated with manganese deposits.
A pseudotrigonal variety of clinochlore. See also:penninite
Eng. The original and typical series of Carboniferous rocks, comprising
the Upper Old Red Sandstone, the Mountain limestone, the Millstone grit,
and the Coal Measures. Standard, 2