A drive employing an auxiliary belt that bears against the surface of the
conveying belt as it passes around the drive pulley to increase the
pressure between the conveyor belt and the drive pulley.
a. Corn. To take down and remove the softer part of a lode, before
removing the harder part. See also:gouge
b. The removal of the soft gouge.
c. The excavation made by this operation.
A special electrodeposition cell giving a range of known current densities
for test work. ASM, 1
A monoclinic mineral, (Fe,Mg)2 (Fe,Sn)BO5 ; forms small
black crystals or tabular masses at the contact of granite and
metamorphosed limestone.
A group name for bitumens that vary from gelatinous to hard resinous or
elastic. Believed to represent an emulsion of highly acidic (humic acids)
hydrocarbons with a varying amount of water (as high as 90%). Insoluble in
organic solvents. Tomkeieff
A hydrous ferrous oxalate, Fe2+ C2 O4 2H2 O
, occurring in capillary or botryoidal forms and black shale.
Syn:humboltite; oxalite. Tomkeieff
See:datolite; humboldtine.
Movable-screen type of ore jig. Pryor, 3
See:datolite; humboldtine.
Black acidic organic matter extracted from soils, low-rank coals, and
other decayed plant substances by alkalis. It is insoluble in acids and
organic solvents. AGI
a. A group of coals, including the ordinary bituminous varieties, that
have been formed from accumulations of vegetable debris that have
maintained their morphological organization with little decay. The
majority of them are banded and have a tendency to develop jointing or
cleat. Chemically, humic coals are characterized by hydrogen varying
between 4% to 6%. Tomkeieff
b. Coals in which the attritus may be composed predominately of
transparent humic degradation matter. AGI
c. Introduced in 1906 by H. Potonie to describe coals, the original
organic matter of which underwent change chiefly by humification; i.e.,
through the process of peat formation in the presence of oxygen. Most
seams of coal consist principally of humic coal and the technological
properties vary with their rank, with their petrographic composition, and
with the manner of distribution of mineral inclusions. IHCP
Finely comminuted degradation matter in coal, largely but not altogether
derived from the woody tissues of plants, and like anthraxylon, largely
derived from lignin. AGI
Ratio of the increase in total heat per kilogram of dry air to the rise in
temperature, with constant pressure and humidity ratio.
The quantity of water evaporated per unit of time (usually 1 h) times the
latent heat of vaporization at the evaporating temperature.
Strock, 2
The water-vapor content of the atmosphere. The unmodified term often
signifies relative humidity. See also:absolute humidity;
specific humidity. AGI
An instrument for regulating the humidity in the atmosphere.
Syn:hygrostat
In coal, amorphous brown to black substances formed by natural
decomposition from vegetable substances; insoluble in alkali carbonates,
water, and benzol. Hess
The mineral group alleghanyite, chondrodite, clinohumite, humite,
jerrygibbsite, leucophoenicite, manganhumite, norbergite, ribbeite, and
sonolite; monoclinic and orthorhombic fluosilicates of magnesium, iron,
and/or manganese, with hydroxyl commonly replacing fluorine; similar
physical properties, and structures closely related to those of the
olivines; in metamorphosed dolomitic limestones, or skarns associated with
ore deposits; commonly as chondrodite and clinohumite; at the Tilly Foster
iron mine near Brewster and at Franklin, NJ.
A group of isomorphous minerals consisting of olivine, chondrodite,
humite, and clinohumite, and closely resembling one another in chemical
composition, physical properties, and crystallization. Webster 3rd
Screen used to size moderately small material, vibrated electrically by
solenoid action. Pryor, 3
Peat derived from humic material and in rank corresponding to saprocoll.
Tomkeieff