See:cover
The stress induced by the cover load only and which is uninfluenced by the
proximity of any excavations. Issacson
Lumps of copper too large to pass the screen, which accumulate in the
bottom of the mortar of the stamp. Fay
York. The finest crushed lead ore. Also called coe. Arkell
A hot-blast stove of firebrick on the regenerative principle. Fay
Gray marl. Syn:cushat marl
A cylindrical heavy piece of iron attached to a cable or wire line, making
it descend rapidly into a borehole when the cable or line is not attached
to a string of drilling tools or equipment. Also called bug; bullet;
go-devil. Long
A small tunnel driven horizontally into the rock at right angles to the
face of the quarry. It has two or more crosscuts driven from it parallel
to the face. It is in the ends of these crosscuts that the explosive
charge is generally placed, and the remaining space in the tunnel is
filled up with rock, sand, timbers, or concrete, to act as stemming or
tamping. Same as gopher hole.
See:coyote shooting
A method of blasting using a number of relatively large concentrated
charges of explosives placed in one or more small tunnels driven in a rock
formation. Syn:coyote-hole blasting
A dust trap in which the clean air flows inwards around the outside of the
drill rods, and the dust and chippings are extracted in the airstream
passing through the hollow rods. It includes a drum-type dust container
with filter units. The appliance requires special rods and bits.
See also:dust trap
Abbrev. for clinopyroxenes. CF:opx
A trolley locomotive fitted with a crab or winch for hauling mine cars
from workings where a trolley wire is not installed. Nelson
In bituminous coal mining, one who maintains and operates a crab (electric
motor equipped with a drum and haulage cable mounted on a small truck) to
pull loaded mine cars from working places to haulageways in the mine.
DOT
An iron machine consisting of two triangular uprights between which are
two axles, one above the other. These machines are frequently used in
connection with pumping gear where mine shafts are not deep. Also called
crab. Fay
An incipient breccia having fragments parted by planes of rupture but
showing little or no displacement. It is commonly a chemical deposit.
AGI
A concentric texture of ore minerals in which minute cracks have developed
by shrinkage during crystallization of the original colloid.
Puffs or explosions of gas in blast furnaces. Fay
A dark-colored variety of ozokerite showing a granular fracture.
Tomkeieff
a. A wooden box, longer than wide provided with a movable slide and hopper
and mounted on two rockers, for washing gold-bearing earths. Also known as
rocker cradle.
b. The part of a car dumper in which the car rests when it is dumped.
c. The balance platform for the cage at the bottom of some shafts.
Mason
d. Device by means of which a small diamond or percussive-type drill may
be attached to a drill column or arm. Also called saddle. Long
e. The trough-shaped metal support for a mounted pneumatic drill.
CTD
f. To wash, as gold-bearing gravel in a mining-cradle. Standard, 2
g. Mounting for a rock drill. Pryor, 3
A tipple that dumps cars with a rocking motion. Fay