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back-end man

A worker who works behind the coal-cutter as it moves along the face.
Duties may include cleaning the cuttings from behind the machine and
setting props to support the roof or overhang of coal.
CF:coal-cutter team

back entry

The air course parallel to and below an entry or the entry used for
secondary purposes in two-entry system of mining. Locally, any entry not
having track in it. BCI

backfill

a. Waste sand or rock used to support the roof or walls after removal of
ore from a stope. Pryor, 3
b. Sand or dirt placed behind timber, steel, or concrete linings in shafts
or tunnels. Nelson
c. The process of sealing and filling, and/or the material used to seal or
fill, a borehole when completed, to prevent its acting as a course along
which water may seep or flow into rock formations or mine workings.
Long
d. Material excavated from a site and reused for filling, for example, the
use of stones or coarse gravel for filling draining trenches.
See also:fill

back filling

a. Rough masonry built in behind the facing or between two faces; similar
material used in filling over the extrados of an arch; also, brickwork
used to fill in space between studs in a frame building, sometimes called
brick nogging. ACSG, 1
b. The filling in again of a place from which the rock or ore has been
removed. Ballard

back-filling system

Filling lower or older workings with the waste from newer workings.
See also:overhand stoping; square-set stoping. Hess

backfire

a. A fire started to burn against and cut off a spreading fire.
Nichols, 1
b. An explosion in the intake or exhaust passages of an engine.
Nichols, 1

backfolding

Folding in which the folds are overturned toward the interior of an
orogenic belt. In the Alps, the backward folds are overturned toward the
south, whereas most of the folds are overturned toward the north.
Syn:backward folding

background

a. The abundance of an element, or any chemical property of a naturally
occurring material, in an area in which the concentration is not
anomalous. AGI
b. The slight radioactivity shown by a counter, due to normal
radioactivity from cosmic rays, impurities in the counter, and trace
amounts of radioactivity in the vicinity.

backhand

In bituminous coal mining, one who assists either the machineman or
machine loader to move and set up a coal cutting or loading machine at the
working face. DOT

backhaul

A line that pulls a drag scraper bucket backward from the dump point to
the digging. Nichols, 2

backhaul cable

In a cable excavator, the line that pulls the bucket from the dumping
point back to the digging. Nichols, 1

back heading

a. Eng. The companion place to a main winning. SMRB
b. See:back entry

backhoe

The most versatile rig used for trenching. The basic action involves
extending its bucket forward with its teeth-armed lip pointing downward
and then pulling it back toward the source of power. Carson, 1

back holes

In shaft sinking, raising, or drifting, the holes that are shot last.

backing

a. Timbers fixed across the top of a level supported in notches cut in the
rock.
b. The action of a roof layer of combustible gases flowing uphill against
the direction of the ventilation. BS, 8

backing deals

Boards from 1 to 4 in (2.5 to 10 cm) thick and of sufficient length to
bridge the space between timber or steel sets or between rings in skeleton
tubing. Usually, planks 9 to 12 in (23 to 30 cm) in width are used. Round
poles, either whole or split, light steel rails, ribbed sheet metal, and
reinforced concrete slabs are sometimes used in place of planks. Backing
deals tighten the supports against the ground and also prevent the
collapse of material between the timber or steel sets or rings.
See also:lagging

backing off

A term used to describe the operation of removing excessive body metal
from badly worn bits. Fraenkel

backing sand

Reconditioned sand used for supporting the facing sand, and forming the
main part of a foundry mold. Osborne

backjoint

a. A joint plane more or less parallel to the strike of the cleavage, and
frequently vertical. Zern
b. A rabbet or chase left to receive a permanent slab or other filling.
Webster 3rd

backlash

a. The return or counterblast, as the recoil or backward suction of the
air current, produced after a mine explosion. Also called backblast;
suction blast.
b. The reentry of air into a fan.
c. The violent recoil and whipping movement of the free ends of a rope or
wire cable broken under strain. Long
d. Lost motion, play, or movement in moving parts such that the driving
element (as a gear) can be reversed for some angle or distance before
working contact is again made with the secondary element. ASM, 1

back leads

Applied to black sand leads on coastlines which are above high-water mark.
Fay