A small, low fireplace surrounded by three walls, with a tuyere at the
back. Three important types are called: ore hearth, waterback ore hearth,
and Moffet ore hearth; used in smelting. Fay
A blocking operation in which ore is added to an open-hearth bath to
oxidize the bath and to further reduce the carbon. Henderson
a. A term frequently used to indicate two separate factors in an estimate,
namely: (1) ore blocked out; i.e., ore exposed on at least three sides
within reasonable distance of each other; and (2) ore that may be
reasonably assumed to exist, though not actually blocked out; these two
factors should in all cases be kept distinct, because (1) is governed by
fixed rules, while (2) is dependent upon individual judgment and local
experience. The expression ore in sight as commonly used in the past,
appears to possess so indefinite a meaning as to discredit its use
completely. The terms positive ore, probable ore, and possible ore are
suggested.
b. See:developed reserve
The point at which a borehole, crosscut, or other underground opening
encounters an ore vein or deposit; also, the thickness of the ore-bearing
deposit so traversed. Long
A term proposed by Spurr (1923) for a magma that may crystallize into an
ore; the sulfide, oxide, or other metallic facies of a solidified magma.
AGI
See:reflected-light microscope
The study of opaque ore minerals in polished section with a
reflected-light microscope. See also:reflected-light microscopy;
microscopy. AGI
The part of an ore, usually metallic, which is economically desirable, as
contrasted with the gangue. See also:ore
Said of an orebody that is only partly developed, and the values of which
can be only approx. determined. See also:probable ore
A vertical or inclined passage for the downward transfer of ore; equipped
with gates or other appliances for controlling the flow. An orepass is
driven in ore or country rock and connects a level with the hoisting shaft
or with a lower level. See also:ore chute
Ore, or other mineral product, becomes personal property when detached
from the soil in which it is imbedded. Ricketts
A long and relatively thin deposit commonly formed at the intersection of
two planes. See also:pipe
A place where dressed ore is kept. Fay
a. Excavation near a hoisting shaft into which ore from stopes is moved,
preliminary to hoisting. Pryor, 3
b. Used in a phrase such as a rich pocket of ore, to describe an unusual
concentration in the lode. Pryor, 3
See:ore dressing
A well-defined area containing ore deposits of a particular kind; e.g.,
the porphyry copper deposits of the Southwestern United States. Related
to, but not exactly synonymous with, metallogenic province, which need not
contain economic ore deposits.
a. The term is usually restricted to ore of which the grade and tonnage
have been established with reasonable assurance by drilling and other
means. Nelson
b. The total tonnage and average value of proved ore, plus the total
tonnage and value (assumed) of the probable ore. Hoover
c. A mine's substantial asset, without which none of the surface works are
economically viable. A body of ore that has been proved to contain a
sufficient tonnage of amenable valuable mineral to justify the mining
enterprise. The British Institution of Mining and Metallurgy, which
regulates the professional standards of its membership, considers that the
term ore reserves should be restricted to ore of which the quantity and
grade have been established with reasonable assurance by a responsible,
professionally qualified person. Additional ore insufficiently developed
or tested for inclusion in ore reserves should be clearly described in
simple terms best suited to the circumstances; modes of mineral occurrence
vary too widely to permit standardization of categories. Pryor, 3
d. S. Afr. Orebodies made available for mining through drives connected by
winzes (a connection driven down) and raises (a connection driven up),
thus forming blocks that are accessible from four sides. Some companies
record partially developed ore reserves in which this making of blocks has
not been completed. Newcomers in gold mining occasionally speak of ore
reserves when they mean the orebodies contained in a mining area and in
copper mining this method of expression has been accepted by large
concerns. Beerman
e. See:reserve
The process in which a portion (sample of ore) is selected in such a way,
that its composition will represent the average composition of the entire
bulk of ore. Such a selected portion is a sample, and the art of properly
selecting such a sample is called sampling. Newton, 1
A cradle, frame, jigging machine, washer, or other device or machine used
in separating the metal from broken ore, or ore from worthless rock.
Standard, 2
a. An elongate pipelike, ribbonlike, or chimneylike mass of ore within a
deposit (usually a vein), representing the more valuable part of the
deposit. Syn:shoot
b. Concentration of primary ore along certain parts of a rock opening.
Bateman, 2
c. A large and visually rich aggregation of mineral in a vein. It is a
more or less vertical zone or chimney of rich vein matter extending from
wall to wall, and has a definite width laterally. Sometimes called pay
streak, although the latter applies more specif. to placers.
d. An area of payable lode surrounded by low values. See also:shoot
Spalding
A tabular sheet of magmatic ore, injected in a liquid state along the
bedding planes of a sedimentary or other layered formation.