See:heintzite
A yellowish-brown, amorphous hydrocarbon found in Burma, which emits a bad
smell on burning. Tomkeieff
A method for draining combustible gases from coal seams in which
superjacent entries are developed over the coal seam being mined. The
entries are located from about 80 to 138 ft (24 to 42 m) above the seams
to be mined and are often supplemented with up or down boreholes drilled
perpendicular to the walls of the entries. Also known as the superjacent
roadway system. Virginia Polytechnic
A monoclinic mineral, Fe2 Si2 O5 (OH)4 .2H
2 O ; fine-grained to cryptocrystalline or fibrous; at Hibbing, MN;
Blaine County, ID; and in Canada, Greenland, Finland, and Sweden.
A vertical-bar graph representing a frequency distribution, in which the
height of bars is proportional to frequency of occurrence within each
class interval and, due to the subdivision of the x-axis into adjacent
class intervals, there are no empty spaces between bars when all classes
are represented in a sample so graphed. Histograms are used to depict
particle-size distribution in sediments. AGI
A major branch of geology that is concerned with the evolution of the
Earth and its life forms from its origins to the present day. The study of
historical geology therefore involves investigations into stratigraphy,
paleontology, and geochronology, as well as the consideration of
paleoenvironments, glacial periods, and plate-tectonic motions. It is
complementary to physical geology. Not to be confused with history of
geology. See also:geology
Eng. To find, prove, or cut into a coal seam or fault. Fay
a. Step cut in rock face to hold timber support in underground working.
Syn:stip
b. N. of Eng. A minor geological fault or roll in the coal seam.
Trist
c. Scot.; Eng. A minor dislocation of a vein or stratum not exceeding in
extent the thickness of the vein or stratum. Fay
d. A hole cut in the side rock, when this is solid enough to hold the cap
of a set of timbers permitting the leg to be dispensed with. Fay
e. A fault. Fractures and dislocations of strata common in coal measures,
accompanied by more or less displacement. Raistrick
f. A connection between two machines. Nichols, 1
g. To attach trams to hauling ropes by short chains. Fay
h. A sudden stoppage of pumping machinery. Standard, 2
i. To dig or pick holes or places to receive the ends of timbers.
Standard, 2
a. S. Wales. A system of regulating the distance between the faces of
stalls in longwall work. Fay
b. See:stepped longwall
A miner who cuts places in the coal, ore, or wall in which to rest or
place timbers to prevent rock from falling. Fay
a. The person who runs trams into or out of the cages, gives the signals,
and attends at the shaft when miners are riding in the cage.
See also:cager
b. One who works at the bottom of a haulage slope or plane, engaging the
clips or grips by means of which mine cars are attached to a hoisting
cable or chain used for haulage up a steep incline to the mine surface.
Also called hitcher-on. See also:hitcher-on; onsetter. DOT
The person employed at the bottom of a shaft or slope to put loaded cars
on, and take empty cars off the cage. See also:hitcher
Installing bars in hitches either cut or drilled in the rib, thereby
eliminating the need for legs. Hitch holes may be provided for each
individual bar. Coal Age, 3
Explosive containing low-density gelatin; used for submarine blasting.
Bennett
A former name for yttromicrolite.
a. Forest of Dean. A cart or sled for conveying coal in the stalls of thin
seams. Fay
b. A tray or trough with a pole handle that is borne on the shoulder, for
carrying mortar, brick, or similar load. Webster 3rd
Variation on Harz jig in which the plunger (piston) has differential
motion. See also:Harz jig
See:breakdown
See:hoegbomite
An orthorhombic mineral, C14 H8 O2 ; forms delicate
yellow needles associated with chlorides and sulfur deposited by gases at
a burning coalbed on Spitzbergen Island (anthraquinone).
A monoclinic mineral, (Mg3 (AsO4 )2 .8H2 O);
vivianite group, with Mg replaced by Co toward erythrite; in white
crystals resembling gypsum; also columnar; a secondary mineral formed by
alteration of arsenate minerals. Syn:hoernesite