A tunneling device invented by J. H. Greathead, first used in London in
1869, and still widely used today. His invention included a circular
cutting edge forced through the ground by hydraulic jacks, a cast-iron
lining assembled by bolts, and grouting behind the lining with the aid of
compressed air and a special mixer. Hammond
Salt in large lumps or crystals. Kaufmann
See:ditch
Mixed sulfonation products from oil refinery cracking processes; used in
detergency and as main constituent of a series of flotation agents chiefly
concerned with the concentration of iron minerals. Also refers to the
initial solution generated from the acceleration of phosphate concentrate.
Pryor, 3
A monoclinic mineral, (Fe2+ ,Fe3+ )2-3 Si2
O5 (OH)4 ; kaolinite-serpentine group; forms green granules
in the taconite of the Mesabi Range, MN, and the Gogebic iron formation of
northern Wisconsin.
A dull, dark green rock, uniformly fine-grained with conchoidal fracture,
containing grains of greenalite in a matrix of chert, carbonate minerals,
and ferruginous amphiboles. AGI
A system of sintering powdery metalliferous ores. Osborne
A dust-sampling apparatus evolved by the U.S. Bureau of Mines that makes
use of the principle of impingement of the dust-laden air at high velocity
on a wetted glass surface, together with that of bubbling the air through
a liquid medium. See also:midget impinger
Usually some cryptocrystalline variety of quartz stained green. Also may
be chalcedony of natural green color. See also:chrysoprase
A mixture of ingredients for gunpowder before the intimate mixing in the
incorporating mill. Webster 3rd
The mineral melanterite, hydrous ferrous sulfate, Fe2+ SO4
.7H2 O . Syn:green vitriol
A furnace taphole in which clay is not properly set, and through which the
drill may break and let iron out unexpectedly. Fay
See:dufrenite
See:columbite
See:cryolite
See:pyromorphite
See:verde antique
A deep-sea terrigenous deposit characterized by the presence of a
considerable proportion of glauconite and CaCO3 in variable amounts
up to 50%. Holmes, 1
A hexagonal mineral, 2[CdS] ; forms earthy incrustations and coatings on
sphalerite and other zinc ores; rarely in amygdules.
See also:xanthochroite
A rose-colored variety of titanite (sphene) containing up to 3% MnO.
A miner's term for a roof that has not broken down or shows no sign of
taking weight. Fay