a. Ore, the amount, content, and minability of which have been proven by
development work or by drilling developed ore. Syn:developed reserve
AGI
b. A body of ore exposed, explored, and sampled for valuation purposes on
all four sides of the panel formed by driving, winzing, and raising.
Pryor, 3
c. See:reserves
A type of normal faulting in which the crust is divided into structural or
fault blocks of different elevations and orientations. It is the process
by which block mountains are formed. AGI
A thin accumulation of usually angular blocks, lying on bedrock without a
cliff or ledge above as apparent source. Block fields occur on high
mountain slopes above the tree line. Syn:felsenmeer
a. A small hole drilled into a rock or boulder into which an anchor bolt
or a small charge or explosive may be placed. Long
b. Used by drillers, miners, and quarry workers for a method of breaking
undesirably large blocks of stone or boulders by the discharge of an
explosive loaded into shallow holes drilled into the blocks or boulders.
Long
c. A relief hole designed to remove part of the burden from a subsequent
shot; used in coal mining.
A person whose duty it is to break up and reduce to safe and convenient
size, by blasting or otherwise, any large blocks or pieces of rock that
have been blown down by the miners. Fay
See:pop shot
The breaking of boulders by loading and firing small explosive charges in
small-diameter drilled holes.
In a crusher, obstruction of the crushing zone by clayey material or by
rock that refuses to break down and pass to discharge. Syn:packing
A method of holding mine timber sets in place. Blocks of wood are set on
the caps directly over the post supports and have a grain of block
parallel with the top of the cap; wedges are driven tightly between the
blocks and the roof. See also:block
a. Exposing an orebody by means of development openings, on at least three
sides, in preparation for continuous extraction; the opening of a deep
lead deposit. See also:block
b. As applied to coal reserves, acquiring coal and mining rights in
contiguous areas to form a continuous area and in a desirable shape for
planned future mining.
c. Aust. Laying or staking out gold-bearing gravel deposits in square
blocks in order to facilitate systematic washing.
d. In economic geology, delimitation of an orebody on three sides in order
to develop it, i.e., to make estimates of its tonnage and quality. The
part so prepared is an ore block. AGI
Estimating the value of a block from a set of nearby sample values using
kriging.
Applied to the various processes involved in roofing slate manufacture,
which include drilling and wedging, cutting, sawing, etc. AIME, 1
Mica with a minimum thickness of 0.007 in (0.18 mm) and a minimum usable
area of 1 in2 (6.45 cm2 ), full trimmed unless otherwise
specified. Skow
A mountain that is formed by block faulting. The term is not applied to
mountains that are formed by thrust faulting. Syn:fault-block mountain
AGI
A general failure of the hanging wall. In the gold mines of South Africa
and the Michigan copper mines, block movements have been experienced.
Nelson
a. To fill and seal undesirable openings, fissures, or caving zones in a
borehole by cementation or by lining the borehole with pipe or casing.
Also called blank off; case off; seal off. Long
b. To secure a mine opening against the flow or escape of gas, air, or
liquid by erecting rock, concrete, steel, wood, or cloth barriers.
Long
c. To erect barriers to prevent workers from entering unsafe areas in
underground workings. Long
To delineate the area in which a desirable mineral occurs by systematic
core drilling or by underground openings. Long
These consist of timber blocks, 8 to 12 in (20.3 to 30.5 cm) square, set
in transverse rows in a sluicebox; they are arranged so that in contiguous
rows the joints are staggered to prevent the development of longitudinal
cracks. It is usual to separate adjacent rows by means of a strip of
ordinary riffle scantling. Griffith
Used in quarrying to describe granite that has three sets of joints
occurring at right angles to each other. Streefkerk
a. A pillar mining system in which a series of entries, panel entries,
rooms, and crosscuts are driven to divide the coal into blocks of approx.
equal size, which are then extracted on retreat. Development openings are
most commonly driven between 15 ft and 20 ft (4.6 m and 6.1 m) wide.
Pillars are most commonly 40 to 60 ft (12.2 to 18.3 m) wide and from 60 to
100 ft (18.3 to 30.5 m) long. Woodruff
b. A system of control in which a number of units, for example, powered
supports, are operated as a group. NCB
block system of stoping and filling
See:overhand stoping; Brown panel system.