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backstamp

The maker's name and/or trademark stamped on the back of pottery flatware
or under the foot of hollowware. Dodd

backstay

A drag or trailer fixed at the back of a haulage train (or set) as a
safety device when going uphill. See also:drag
Mason

backstone

Eng. Shaly mudstone used for cooking slabs, quarried near Delph,
Yorkshire. Also, a bed in the Staffordshire Coal Measures. Arkell

back stope

To mine a stope from working below.

back stopes

Overhead stopes; stopes worked by putting in overhead holes and blasting
down the ore. CTD

backstroke jigging

A process in which strong suction is advocated at all times with the
dense-medium process, since none of the bone medium must be allowed to get
over into the washed coal. Mitchell

backup gear

See:reverse-feed gear

back vent

Scot. An air course alongside the pillar in wide rooms.

backwardation

The situation when the cash or spot price of a metal is greater than its
forward price. A backwardation occurs when a tight nearby situation exists
in a metal. The size of the backwardation is determined by differences
between supply and demand factors on the nearby positions compared with
the same factors on the forward position. There is no official limit to
the backwardation. The backwardation is also referred to as the "back."
Wolff

backward folding

See:backfolding

backwash

a. In uranium leaching, flushing from below of colloidal slime from ion
exchange column after adsorption cycle. The cleaning of sand filters.
b. Water or waves thrown back by an obstruction such as a ship,
breakwater, cliff, etc. AGI
c. The return flow of water seaward on a beach after the advance of a
wave. See also:backrush

back work

a. Any kind of operation in a mine not immediately concerned with
production or transport; literally work behind the face; repairs to roads.
Mason
b. See:back coming; back splinting.

bacon

Eng. Fibrous carbonate of lime, also known as beef and horseflesh; Isle of
Portland. See also:beef

bacon stone

a. Eng. Calcspar colored with iron oxide, Bristol. Arkell
b. An old name for a variety of steatite (rock gypsum), alluding to its
greasy luster. See also:speckstone

baculite

A crystallite that appears as a dark rod. AGI

bad air

Air vitiated by powder fumes, noxious gases, or respirable dust.

baddeleyite

A monoclinic mineral, ZrO2 ; may contain some hafnium, titanium,
iron, and thorium.

badlands

A region nearly devoid of vegetation where erosion has produced, usually
in unconsolidated or poorly cemented clays and silts, a dense and
intricate drainage pattern with short steep slopes and sharp crests and
pinnacles. Specif., the Badlands of the Dakotas.

bad top

A coal mining term indicating a weak roof. Bad top sometimes develops
following a blast. Kentucky

baeumlerite

A colorless chloride of potassium and calcium, KCl.CaCl2 .
Intergrown with halite and tachyhydrite. Orthorhombic.
Syn:chlorocalcite

baff ends

Long wooden edges for adjusting linings in sinking shafts during the
operation of fixing the lining. Zern