Method of determining the velocity distribution by recording in a
borehole. Schieferdecker
A heavy steel ring, about 3 in or 4 in (7.6 cm or 10.2 cm) inside
diameter, used in withdrawing a bar stuck or frozen in a skull or iron.
The ring is placed on the bar, a wedge inserted, and the bar backed out by
sledging on the wedge. Fay
A form of joint between the tubing used to line a collar (or a crossbar)
and the arms (or uprights) of a timber set; developed in the Welsh coal
mines. A Welsh notch is designed to be equally effective in resisting side
and roof pressure. Nelson
See:whim
A hexagonal mineral, Ba4 Ca6 (Si, Al)20 O39
)(OH)2 (SO4 )3 .nH2 O (?) ; cancrinite group.
An extended version of the Udden grade scale, adopted by Chester K.
Wentworth (1891-1969), U.S. geologist, who modified the size limits for
the common grade terms but retained the geometric interval or constant
ratio of 1/2. The scale ranges from clay particles (diameter less than
1/256 mm) to boulders (diameter greater than 256 mm). It is the grade
scale generally used by North American sedimentologists.
See also:Udden grade scale; phi grade scale; grade scale. AGI
A logarithmic grade scale for size classification of sediment particles,
starting at 1 mm and using the ratio 1/2 in one direction (and 2 in the
other), providing diameter limits to the size classes of 1,-1/2,-1/4,
etc., and 1, 2, 4, etc. Syn:grade scale
AGI
Applies to the dissolution of a solid in a liquid. The rate of dissolution
is proportional to the surface area of the solid exposed to the action of
the solvent. Newton, 1
Of or relating to Abraham G. Werner (1749-1817), German mineralogist and
geologist, who classified minerals according to their external
characteristics, advocated the theory of neptunism, and postulated a
worldwide age sequence of rocks based on their lithology. Also, said of
one who is a great, but dogmatic, teacher of geology. n. An adherent of
wernerian beliefs; a neptunist.
A common scapolite. A mineral of the scapolite group, intermediate in
composition between meionite and marialite. Syn:scapolite
Nongelatinous permissible explosive; used in coal mines. Bennett
See:romeite
A plow designed for the extraction of coal pillars and for short, rapidly
advancing development faces. The plow is guided along a panzer conveyor,
but the pulling forces are not transmitted to the conveyor structure. The
plow is automatically advanced at each end of its short run, giving a
rapid face advance. This requires the use of self-advancing supports in
conjunction with hydraulic anchorages. Nelson
See:hard-coal plow
A plow designed for use in a seam with sticky coal. It consists
essentially of two shortened plow bases connected by a heavy tension
spring and carrying two adjustable booms fitted with cutting bits and
connected at the apex to a cutterhead, which plows at roof level or at any
lower level that will bring down the top coal. Nelson
A blasting explosive composed of ammonium nitrate and resin.
Webster 2nd
This consists of a small box containing an iron disk thinly coated with
the rare element selenium. When electromagnetic radiation in the form of
light waves falls on this surface it sets up a potential difference
between the iron and the selenium, which in turn causes a minute electric
current to flow through the sensitive microammeter connected between them.
The magnitude of this current is proportional to the intensity of the
light, and it can be used as a measure. For use with miners' hand lamps
the cell is mounted in a box, the microammeter being housed in the top or
side. The lamp to be tested is placed in the box on a turntable, and the
candlepower is read off directly since the instrument is already
calibrated. Standard, 2
In mineral analysis, a balance used to determine the specific gravity of
heavy liquids which are in turn used to determine the specific gravity of
mineral grains by a sink-float method. It is a modification of a Walker
steelyard (beam) balance. Also called: Mohr balance. CF:Jolly balance;
Walker balance.
A liquid consisting of eight parts of white phosphorous and eight parts of
sulfur to one part of methylene iodide. Useful in obtaining the refractive
index by the Becke method. Refractive index, 2.05.
A refractory suitable instead of porcelain and quartz glass. Powdered
silicon carbide mixed with silicates and certain metals; resists acids,
alkalis, and temperature shock; is not easily broken.
A method of estimating the effective diameters of particles smaller than
0.06 mm by mixing a sample in a measured volume of water and checking its
density at intervals with a sensitive hydrometer. A test may take several
days. Nelson