A freezing method of shaft sinking, in which a solution of magnesium
chloride, MgCl2 , is circulated through the freezing tubes instead
of brine. The magnesium chloride is cooled to about -30 degrees C at the
refrigerating plant, and this temperature is capable of freezing the
ground without the solution itself freezing and choking the tubes.
Anhydrous ammonia, carbon dioxide, or sulphur dioxide is used as the
refrigerating agent. Nelson
An orthorhombic mineral, Bi2 MoO6 ; forms minute tabular
crystals; at Schneeberg, Saxony, Germany.
A naphtha-burning flame safety lamp for use in gaseous mines. Fay
Winding system in which both cages in a mine shaft are connected to the
same rope, via the drum. Pryor, 3
The wheel that is used in the Koepe winder instead of a winding drum. It
usually consists of a cast-steel hub with steel arms and rim of welded
construction. The diameter of the sheave varies from about 16 to 26 ft
(4.9 to 7.9 m), depending on the size and type of winding rope and the
total load. It is recommended that the ratio of the diameter of the sheave
to the diameter of the rope should be 100:1 and that of the sheave to the
largest wire in the rope, 2,000:1. A Koepe sheave is fitted with renewable
friction linings. See also:sheave; winding sheave. Nelson
a. A system of hoisting without using drums, the rope being endless and
passing over pulleys instead of around a drum. Zern
b. In this system, the hoisting drum is replaced by a large driving sheave
15 to 20 ft (4.6 to 6.1 m) in diameter. The angle of contact of the rope
with the sheave is from 190 degrees to 200 degrees or a little over a half
circle. Driving is done through the friction grip of the sheave on the
rope; therefore, a tail rope is used around a sheave at the bottom of the
shaft to give the necessary pull on the slack side. Lewis
A system where the winding drum is replaced by a large wheel or sheave.
Both cages are connected to the same rope, which passes around some 200
degrees of the sheave in a groove of friction material. The Koepe sheave
may be mounted on the ground adjacent to the headgear or in a tower over
the shaft. The drive to the rope is the frictional resistance between the
rope and the sheave. It requires the use of a balance rope. It is often
used for hoisting heavy loads from deep shafts and has the advantage that
the large inertia of the ordinary winding drum is avoided. The system has
been widely used in Europe for many years, and some large projects in
Great Britain are being equipped with winders of this type.
See also:multirope friction winder
A brake which acts directly on the Koepe sheave and can be applied by the
winding engine operator's brake lever and the other safety devices.
Nelson
See:koettigite
See:coal plow
A monoclinic mineral, ScPO4 .2H2 O ; blue to gray.
Syn:sterrettite
Almandine from Kollen, Bohemia, Czech Republic.
See also:Bohemian garnet
a. A variety of cannel coal occurring locally as lenticles in Swedish alum
shales and containing 30% of ash rich in rare metals, including uranium
and radium. Tomkeieff
b. See:culm
c. A variety of anthraxolite; a hydrocarbon that resembles oil shale.
Crosby
d. A shale impregnated with asphaltite. Hess
The mineral hydrous vanadate of Ni and Zn; in yellow botryoidal crusts; at
Ferghana, Uzbekistan.
Magnesium-rich ultramafic volcanic rock of high temperature origin. The
term was originally applied by Viljoen and Viljoen (1969) to basaltic and
ultramafic lavas near the Komati river, Barberton Mountain Land,
Transvaal, South Africa. Nickel-copper sulfide mineral deposits may be
associated with komatiites.
Barren bedrock underlying tin-bearing gravel. Pryor, 3
Apparatus used to measure dust in mine atmosphere. A measured volume of
air is drawn through a jet so as to impinge on a glass surface coated with
glycerin jelly. The adherent dust is then examined and the particles are
counted under the microscope. Also called Zeiss konimeter.
See also:dust sampling
A tetragonal mineral, FePO4 .3H2 O(?) ; occurs in yellow
spheroidal aggregates; at Liege, Belgium.
Part of the Comanchean, of the continental facies, including coal seams,
occurring in western Canada. CTD
A machine for withdrawing steel arches by means of a controlled hydraulic
system instead of drawing them by hand or winches. Nelson
A double-ended cutter loader; i.e., it can cut and load in both
directions. It consists of four milling heads and one cutter chain
surrounding them; guided by armored conveyor; rope-hauled; cuts at 2.3
ft/s (0.7 m/s) and flits at 10 ft/s (3.0 m/s). The minimum workable seam
thickness is 26 in (66 cm) on gradients from 0 degrees to 12 degrees ;
maximum length of face is 165 yd (151 m); takes 3-1/2 ft (1.07 m) per cut,
continuous mining. Nelson