A felsic plutonic rock, generally adamellite or granodiorite, containing
an amphibole (often hornblende) as an essential dark-colored constituent;
with decreasing quartz it grades through tonalite into normal diorite.
A schistose metamorphic rock consisting principally of hornblende, with
little or no quartz. Unlike amphibolite, it does not need to contain
plagioclase. AGI
a. Eng. Coal worked partly end-on and partly face-on. Fay
b. A variety of cannel coal from South Wales. Fay
c. A coal that emits an odor when burning like that of burnt horn.
Fay
d. Term in use in Saxony, Germany, for a variety of pitch coal similar to
cannel coal. Syn:half end
Solitary coral. AGI
See:hoernesite
A fine-grained rock composed of a mosaic of equidimensional grains without
preferred orientation and typically formed by contact metamorphism.
Porphyroblasts or relict phenocrysts may be present in the granoblastic
matrix. See also:calc-silicate hornfels; pelitic hornfels;
magnesian hornfels. AGI
See:phosgenite
See:calomel
A method for the low-temperature reduction of iron ore by means of a
series of rotary kilns. The kilns are each about 5 ft (1.5 m) in diameter
and 30 ft (9.1 m) in length. The first is used for preheating, the second
for reduction, and the third for cooling the product. Pulverized coal is
used, which makes it readily possible to control the combustion and to
maintain constant temperature. Osborne
See:chlorargyrite; embolite.
A fishing tool specially designed to recover lost collared drill rods or
drill pipe. It consists of a smooth-wall, tapered socket, the larger end
down, equipped with a spring latch, which grips the drill rod under the
collar when it is slid down over the top of the lost drill rod. When the
socket is equipped with a flaring (bell-shaped) mouth, it is called a
bell-mouth socket. Long
In Missouri, calcite stained with carbonaceous material; sometimes dark
enough to be mistaken for sphalerite. Fay
a. Any irregularity cutting out a portion of the vein.
See also:rock fault
b. To split into branches, as a vein of ore in a mine. Standard, 2
c. Rock occupying a channel cut into a coalbed. See also:horseback
AGI
d. A body of sandstone or shale occupying a channel in a coal seam.
See also:horseback
e. In structure, a large block of displaced wall rock caught along a
fault, particularly a high-angle normal fault. AGI
f. A mass of country rock lying within a vein. See also:internal waste
a. See:cutout; swell.
b. A bank or ridge of foreign matter in a coal seam. AGI
c. A large roll in a coal seam. AGI
d. A clay vein in a coal seam. Syn:kettleback
symon fault; washout; slip. AGI
e. A name applied by some writers to floor rolls in coal mines.
AGI
f. Applied in some areas to clay veins; i.e., intrusions of clay into
coalbeds. See also:clay vein; sandstone dike. AGI
g. Eng. A mass of stone with a slippery surface in the roof. In shape, it
resembles a horse's back. SMRB
h. Natural channels cut or washed away by water in a coal seam and filled
up with shale and sandstone. Sometimes, a bank or ridge of foreign matter
in a coal seam. Fay
i. A portion of the roof or floor that bulges or intrudes into the coal.
Fay
j. A mass of country rock lying within a vein or bed. Fay
k. A piece of slate, flat underneath, thick in the middle, and running out
to a thin edge upon each side. See also:kettle bottom
l. Eng. A tree branch that has been horizontally embedded, carbonized, and
compressed into lenticular shape in shale immediately above a coalbed.
Chem. Indust.
m. A term used in Maine for a low and somewhat sharp ridge of sand or
gravel; also, but not generally, a ridge of rock that rises for a short
distance with a sharp edge. A hogback. Fay
In bituminous coal mining, one who excavates horseback (banks or ridges of
dirt or rock in the coal seam) in a strip mine with a power shovel.
DOT
See:bornite
Bar pulled around by draft animal to actuate winding capstan.
Syn:whim gin
The work performed or the energy consumed by working at the rate of 1 hp
for 1 h (2.68 MJ), being equal to 1,980,000 ft.lbf (2.68 X 106
N.m). Abbrev., hp.h. Webster 3rd
The work done in ventilating a mine or part of a mine is measured by the
quantity circulated multiplied by the ventilating pressure required, the
quantity being measured in cubic feet per minute (cubic meters per minute)
and the pressure in pounds per square foot (kilograms per square meter).
The horsepower required is, therefore, this product divided by 33,000.
Sinclair, 1
The effort necessary to maintain the normal operating speed of a conveyor
under a rated capacity load. To this must be added the effort of
acceleration, drive losses, etc., to arrive at a final driving effort.
Horsepower pull may be referred to in terms such as effective tension,
chain pull, turning effort, gear tooth pressure, etc.
See also:effective belt tension