See:roller bit
A drivepipe or casing shoe with a serrated or toothed cutting edge.
Long
Odontolite; fossil tooth material.
A mine-safety expression used to describe those mines or areas of mines
that are too wet to propagate explosions even though they are not rock
dusted. Too wet is when water exudes from a ball of dust when it is
squeezed in the hands.
a. The surface around a mine shaft; the outside. Jones, 1
b. A mine roof; the upper part of a coalbed separated from the rest by a
seam or parting. Fay
c. The apex of a vein. Hess
d. See:cap; blue cap; overburden.
The words top and apex as applied to mineral veins were not a part of the
miner's terminology prior to the adoption of the U.S. Mining Law of 1872,
but were words used by legislators to convey the intent of the formulators
of that law. CF:apex
A triclinic mineral, Al2 (F,OH)2 SiO4 ;
pseudo-orthorhombic; colorless to pale blue, pale yellow to pinkish-beige
("sherry" topaz); defines hardness 8 on the Mohs scale; in cavities in
granites, granite pegmatites, and rhyolites, and in surrounding
metamorphic rocks; may be of gem quality. CF:false topaz; Scotch topaz;
Spanish topaz.
See:topazite
A hypabyssal rock composed almost entirely of quartz and topaz (Johannsen,
1920). Syn:topazfels; topazoseme; topaz rock. AGI
A yellow variety of andradite resembling topaz.
See:topazite
See:gold topaz
See:topazite
Eng. Often applied to the highest bed in a quarry. In Dorset and Somerset,
the upper division of the Inferior Oolite. Arkell
The method by which the bench is removed from above, as with a dragline.
See also:benching
Fireclay brick for use in lining the top section of a blast furnace.
ARI
A worker at the top of a shaft to superintend the operation of lowering
and raising of a cage. At most mines, duties include removing loaded cars
from the cage and placing empty cars on the cage. See also:cager
Fay
That part of a mine roof that has to be taken down to give headroom on
roadways. Fay
Standard grade of diamonds. Hess
a. A machine cut made in the upper limit of the workable section of a coal
seam. See also:overcut
b. A horizontal cut or groove made in coal at or near the top of the
working face. See also:middle cut; bottom cut.
A cutting machine designed esp. for cutting through the seam at a high
level above the footwall. Stoces