Next page Previous page

shear modulus

Also known as the modulus of rigidity, it equals the shear stress divided
by the shear strain. Hammond

shear of ore

Ore shoot or orebody. von Bernewitz

shearpin

A small soft-metal pin, connecting or pinning together two parts of a tool
that will break by shearing if an excessive load is placed on the pinned
components. The shearing of the pin prevents damage to the overloaded
components; thus it is a safety device. Long

shear plane

A fracture that produces a positive draw. It differs from a weight break
in that the character of the fracture is less ragged and heaving takes
place over the unwrought coal instead of the waste. Briggs

shear rivet

Soft copper rivets used in the Hall-Rowe wedge to connect the drive and
pilot wedges; they can be sheared off to leave the drive wedge as a
permanent reference in the borehole at the point at which the hole is to
be deflected. Long

shear slide

A slide produced by shear failure, usually along a plane of weakness, as
bedding or cleavage. AGI

shear steel

A steel produced by heating blister steel (sheared to short lengths) to a
high heat, welding by hammering or rolling, or both, and finally finishing
under the hammer at the same or slightly greater heat. Webster 3rd

shear strain

Angular displacement of a structural member due to a force acting across
it, measured in radius. See also:shear modulus

shear strength

a. The stress or load at which a material fails in shear. Nelson
b. A measure of the shear value of a fluid. Also a measure of the gelling
properties of a fluid. Brantly, 1
c. The internal resistance of a body to shear stress, typically including
a frictional part and a part independent of friction called cohesion.
AGI

shear stress

a. The shear force operating in a material, measured per unit of
cross-sectional area. See also:stress; shear modulus; punching shear.
Hammond
b. The stress component tangential to a given plane. Also called shearing
stress; tangential stress. ASCE

shear structure

Any rock structure caused by shearing, e.g., crushing, crumpling, or
cleavage. AGI

shear wave

See:S wave

shear zone

a. A tabular zone of rock that has been crushed and brecciated by many
parallel fractures due to shear strain. Such an area is often mineralized
by ore-forming solutions. Syn:sheeted zone; sheeted-zone deposit.
AGI
b. Hogback. Zern

sheath

a. To enclose or encase with a covering. Carson, 1
b. A chemical compound or mixture incorporated in a sheathed explosive
unit that forms a flame-inhibiting cloud on detonation of the explosive.
CFR, 4

sheathed explosive

A permitted explosive surrounded by a sheath containing a noncombustible
powder. The powder acts as a cooling agent and reduces the temperature of
the resultant gases of the explosion, and therefore reduces the risk of
these hot gases causing a combustible gas ignition.
See also:eq

sheathed explosive unit

A device consisting of an approved or permissible explosive covered by a
sheath encased in a sealed covering and designed to be fired outside the
confines of a borehole. CFR, 4

sheathing driver

Essentially a paving breaker, an impact hammer driven by air, designed and
adapted for driving wood sheathing. Carson, 1

sheave

Grooved pulley wheel much used in underground rope haulage.
See also:Koepe sheave; tail sheave; winding sheave. Pryor, 3

sheave block

A pulley and a case provided with a means to anchor it. Nichols, 1

sheave wheel

See:sheave

shed

a. Eng. A thin, smooth parting in rocks, having both sides polished.
b. Eng. A very thin layer of coal.
c. A divide of land; e.g., a watershed. AGI