A spring-tensioned aluminum pole (of two sections) with a holder to hold a
flashlight in a horizontal position with an adjustable screw aligned with
the push button switch of the flashlight. If there is conversion of the
mine roof (back), the adjustment screw will depress, putting on the light
to warn a miner in the area. Sometimes accompanied by a conversion gauge
(measures in thousandths). See also:guardian angel
An offset swivel coupling that supports the weight of the rods when
whipstocking. Long
a. A platform built in a derrick as a safe working place for workers who
must be up the derrick to handle elevators, casing, drill rods, etc.
Long
b. A platform with a hinged-door opening, over a shaft while being sunk,
esp. where blasted materials are hoisted with a muck bucket. After the
bucket is hoisted, the hinged door is closed to prevent any material from
falling back onto workers in the shaft.
A timber placed near the face of working places to afford protection for
the workers at the face. It must be set like a line timber and with equal
care. Kentucky
A term used for short-flame explosives before the introduction of
permissible explosives. Fay
A cable-winding device anchored at the upper grade of an inclined face and
having its cable attached to the head of the coal cutter or cutter loader
to assist overcoming frictional resistance of the cutter or loader while
in operation against the grade.
a. An appliance to stop or control cars near the shaft at the pit bottom
or at the top of incline haulages. Nelson
b. On a hoisting apparatus, a check by which a cage or lift may be
prevented from falling. Standard, 2
c. An automatic device on a hoisting engine designed to prevent
overwinding. Fay
A switch that provides shunt protection in blasting circuits between a
blast site and the switch used to connect a power source to the blasting
circuit. CFR, 5
a. Nonsparking tools made of beryllium-copper alloy for use in explosive
atmospheres. Hess
b. A tool such as a catching hook, a grappling tong, a fish head, or a
bell screw, for recovering broken boring tools, picking up material, etc.,
at the bottom of boreholes. Fay
A pressure-relief valve. Long
a. Essentially, a diarsenide of cobalt but usually with a considerable
amount of iron, and rarely, a small amount of nickel.
Syn:cobalt lollingite
b. An orthorhombic mineral, 4[CoAs2 ] ; loellingite group;
dimorphous with clinosafflorite; metallic; tin-white tarnishing to dark
gray; sp gr, 7.4; in hydrothermal veins.
See:mucker
a. A depression in a coal seam, mine floor, or roof. AGI
b. A depression produced by downwarping of beds on the downthrown side of
a fault such that they dip toward the fault. AGI
c. The difference between the sagging path a conveyor belt actually takes
due to the imposed load of material and its own weight, and the
theoretical plane tangent to the top of the supporting idler rolls.
d. See also:rod sag
The minimum tension in any portion of the carrying run of belt necessary
to prevent excessive sag of the belt between belt idlers.
Bolts installed at intersections to measure roof sag. A sag bolt is a
12-ft (3.5-m) unit put in without a bearing plate. It is securely anchored
in the 12-ft horizon with the aid of a heavy nut, and extends about 2 in
(5 cm) from the hole. Three 1/2-in (1.3-cm) strips of colored
pressure-sensitive tape are wrapped around the extending section of the
bolt, beginning with green at the roof line, then yellow and red. The
color bands provide a simple, economical means of detecting roof sag at a
glance. Coal Age, 3
A tape correction applied to the apparent length of a level base line to
counteract the sag in measuring tape. Hammond
a. An acicular variety of rutile in reticulated twin groups.
b. See:rutilated quartz; Venus hairstone. Etymol: Latin "sagena" large
fishing net. Adj: sagenitic.
Occurring as needles or plates intersecting in a gridlike or grill-like
manner. CF:acicular
Transparent quartz containing acicular rutile, tourmaline, goethite,
actinolite, or other mineral. See also:Thetis hairstone;
Venus hairstone; rutilated quartz.
A coarse fireclay, often forming the floor of a coal seam, so called
because it is used for making saggers or protective boxes in which
delicate ceramic pieces are placed while being fired. Etymol: corruption
of "safeguard." Also spelled: seggar. Syn:sagre
A bending moment that produces concave bending at midspan of a simply
supported beam, generally termed a positive bending moment. It is the
opposite of a negative or hogging moment, which would occur at the
supports. Hammond