| A |
| Acidic precipitation |
Snow and rain that have a low
pH, caused by sulphur dioxide and nitric oxide gases from industrial
activity released into the atmosphere. |
| Acidic rocks |
Igneous rock carrying a high
(greater than 65%) proportion of silica. |
| Acid mine drainage |
Acidic run-off water from mine
waste dumps and mill tailings ponds containing sulphide minerals. Also
refers to ground water pumped to surface from mines. |
| Adit |
An opening driven horizontally
into the side of a mountain or hill for providing access to a mineral
deposit. |
| Aerial magnetometer |
An instrument used to measure
magnetic field strength from an airplane. |
| Aeromagnetic survey |
A geophysical survey using a
magnetometer aboard, or towed behind, an aircraft. |
| Agglomerate |
A breccia composed largely or
entirely of fragments of volcanic rocks. |
| Agglomeration |
A method of concentrating
valuable minerals based on their adhesion properties. |
| Agitation |
In metallurgy, the act or
state of being stirred or shaken mechanically, sometimes accomplished by
the introduction of compressed air. |
| Airborne survey |
A survey made from an aircraft
to obtain photographs, or measure magnetic properties, radioactivity,
etc. |
| Alloy |
A compound of two or more
metals. |
| Alluvium |
Relatively recent deposits of
sedimentary material laid down in river beds, flood plains, lakes, or at
the base of mountain slopes. (adj. alluvial) |
| Alpha meter |
An instrument used to measure
positively charged particles emitted by radioactive materials. |
| Alpha ray |
A positively charged particle
emitted by certain radioactive materials. |
| Alteration |
Any physical or chemical
change in a rock or mineral subsequent to its formation. Milder and more
localized than metamorphism. |
| Amorphous |
A term applied to rocks or
minerals that possess no definite crystal structure or form, such as
amorphous carbon. |
| Amortization |
The gradual and systematic
writing off of a balance in an account over an appropriate period. |
| Amphibolite |
A gneiss or schist largely
made up of amphibole and plagioclase minerals. |
| ANFO |
Acronym for ammonium nitrate
and fuel oil, a mixture used as a blasting agent in many mines. |
| Annual report |
The formal financial
statements and report on operations issued by a corporation to its
shareholders after its fiscal year-end. |
| Anode |
A rectangular plate of metal
cast in a shape suitable for refining by the electrolytic process. |
| Anomaly |
Any departure from the norm
which may indicate the presence of mineralization in the underlying
bedrock. |
| Anthracite |
A hard, black coal containing
a high percentage of fixed carbon and a low percentage of volatile
matter. |
| Anticline |
An arch or fold in layers of
rock shaped like the crest of a wave. |
| Apex |
The top or terminal edge of a
vein on surface or its nearest point to the surface. |
| Ash |
The inorganic residue
remaining after ignition of coal. |
| Assay |
A chemical test performed on a
sample of ores or minerals to determine the amount of valuable metals
contained. |
| Assay foot (metre, inch, centimetre) |
The assay value multiplied by
the number of feet, metres, inches, centimetres across which the sample
is taken. |
| Assay map |
Plan view of an area
indicating assay values and locations of all samples taken on the
property. |
| Assessment work |
The amount of work, specified
by mining law, that must be performed each year in order to retain legal
control of mining claims. |
| Authorized capital |
see capital stock. |
| Autogenous grinding |
The process of grinding ore in
a rotating cylinder using large pieces of the ore instead of
conventional steel balls or rods. |
| Back |
The ceiling or roof of an
underground opening. |
| Backfill |
Waste material used to fill
the void created by mining an orebody. |
| Background |
Minor amounts of radioactivity
due not to abnormal amounts of radioactive minerals nearby, but to
cosmic rays and minor residual radioactivity in the vicinity. |
| Back sample |
Rock chips collected from the
roof or back of an underground opening for the purpose of determining
grade. |
| Backwardation |
A situation when the cash or
spot price of a metal stands at a premium over the price of the metal
for delivery at a forward date. |
| Balance sheet |
A formal statement of the
financial position of a company on a particular day, normally presented
to shareholders once a year. |
| Ball mill |
A steel cylinder filled with
steel balls into which crushed ore is fed. The ball mill is rotated,
causing the balls to cascade and grind the ore. |
| Banded iron formation |
A bedded deposit of iron
minerals. |
| Basalt |
An extrusive volcanic rock
composed primarily of plagioclase, pyroxene and some olivine. |
| Basal till |
Unsorted glacial debris at the
base of the soil column where it comes into contact with the bedrock
below. |
| Basement rocks |
The underlying or older rock
mass. Often refers to rocks of Precambrian age which may be covered by
younger rocks. |
| Base camp |
Centre of operations from
which exploration activity is conducted. |
| Base metal |
Any non-precious metal (eg.
copper, lead, zinc, nickel, etc.). |
| Basic rocks |
Igneous rocks that are
relatively low in silica and composed mostly of dark-colored minerals.| |
| Batholith |
A large mass of igneous rock
extending to great depth with its upper portion dome-like in shape.
Similar, smaller masses of igneous rocks are known as bosses or plugs. |
| Bauxite |
A rock made up of hydrous
aluminum oxides; the most common aluminum ore. |
| Bear market |
Term used to describe market
conditions when share prices are declining. |
| Bedding |
The arrangement of sedimentary
rocks in layers. |
| Beneficiate |
To concentrate or enrich;
often applied to the preparation of iron ore for smelting. |
| Bentonite |
A clay with great ability to
absorb water and which swells accordingly. |
| Bessemer |
An iron ore with a very low
phosphorus content. |
| Bio-leaching |
A process for recovering
metals from low-grade ores by dissolving them in solution, the
dissolution being aided by bacterial action. |
| Biotite |
A platy magnesium-iron mica,
common in igneous rocks. |
| Bit |
The cutting end of a drill
frequently made of an extremely hard material such as industrial
diamonds or tungsten carbide. |
| Blackjack |
A miner's term for sphalerite
(zinc sulphide). |
| Black smoker |
Volcanic vent found in areas
of active ocean floor spreading, through which sulphide-laden fluids
escape. |
| Blaster |
A mine employee responsible
for loading, priming and detonating blastholes. |
| Blast furnace |
A reaction vessel in which
mixed charges of oxide ores, fluxes and fuels are blown with a
continuous blast of hot air and oxygen-enriched air for the chemical
reduction of metals to their metallic state. |
| Blasthole |
A drill hole in a mine that is
filled with explosives in order to blast loose a quantity of rock. |
| Blister copper |
A crude form of copper
(assaying about 99%) produced in a smelter, which requires further
refining before being used for industrial purposes. |
| Block caving |
An inexpensive method of
mining in which large blocks of ore are undercut, causing the ore to
break or cave under its own weight. |
| Board lot |
One hundred shares. |
| Bond |
An agreement to pay a certain
amount of interest over a given period of time. |
| Boom |
A telescoping, hydraulically
powered steel arm on which drifters, manbaskets and hydraulic hammers
are mounted. |
| Box hole |
A short raise or opening
driven above a drift for the purpose of drawing ore from a stope, or to
permit access. |
| Break |
Loosely used to describe a
large-scale regional shear zone or structural fault. |
| Breast |
A working face in a mine,
usually restricted to a stope. |
| Breccia |
A rock in which angular
fragments are surrounded by a mass of fine-grained minerals. |
| Broken reserves |
The ore in a mine which has
been broken by blasting but which has not yet been transported to
surface. |
| Brunton compass |
A pocket compass equipped with
sights and a reflector, used for sighting lines, measuring dip and
carrying out preliminary surveys. |
| Bulk mining |
Any large-scale, mechanized
method of mining involving many thousands of tonnes of ore being brought
to surface per day. |
| Bulk sample |
A large sample of mineralized
rock, frequently hundreds of tonnes, selected in such a manner as to be
representative of the potential orebody being sampled. Used to determine
metallurgical characteristics. |
| Bullion |
Metal formed into bars or
ingots. |
| Bull market |
Term used to describe
financial market conditions when share prices are going up. |
| Bull quartz |
A prospector's term for white,
coarse-grained, barren quartz. |
| Byproduct |
A secondary metal or mineral
product recovered in the milling process. |
| Cable bolt |
A steel cable, capable of
withstanding tens of tonnes, cemented into a drillhole to lend support
in blocky ground. |
| Cage |
The conveyance used to
transport men and equipment between the surface and the mine levels. |
| Calcine |
Name given to concentrate that
is ready for smelting (i.e. the sulphur has been driven off by
oxidation). |
| Call |
An option to buy shares at a
specified price. The opposite of a "put". |
| Capitalization |
A financial term used to
describe the value financial markets put on a company. Determined by
multiplying the number of outstanding shares of a company by the current
stock price. |
| Capital stock |
The total ownership of a
limited liability company divided among a specified number of shares. |
| Captive stope |
A stope that is accessible
only through a manway. |
| Carbon-in-pulp |
A method of recovering gold
and silver from pregnant cyanide solutions by adsorbing the precious
metals to granules of activated carbon, which are typically ground up
coconut shells. |
| Cash flow |
The net of the inflow and
outflow of cash during an accounting period. Does not account for
depreciation or bookkeeping write-offs which do not involve an actual
cash outlay. |
| Cathode |
A rectangular plate of metal,
produced by electrolytic refining, which is melted into commercial
shapes such as wirebars, billets, ingots, etc. |
| Cesium magnetometer |
An geophysical instrument
which measures magnetic field strength in terms of vertical gradient and
total field. |
| Chalcocite |
A sulphide mineral of copper
common in the zone of secondary enrichment. |
| Chalcopyrite |
A sulphide mineral of copper
and iron; the most important ore mineral of copper. |
| Change house |
The mine building where
workers change into work clothes; also known as the "dry". |
| Channel sample |
A sample composed of pieces of
vein or mineral deposit that have been cut out of a small trench or
channel, usually about 10 cm wide and 2 cm deep. |
| Charter |
A document issued by a
governing authority creating a company or other corporation. |
| Chartered bank |
A financial institution that
accepts deposits and provides loans. |
| Chip sample |
A method of sampling a rock
exposure whereby a regular series of small chips of rock is broken off
along a line across the face. |
| Chromite |
The chief ore mineral of
chromium. |
| Chute |
An opening, usually
constructed of timber and equipped with a gate, through which ore is
drawn from a stope into mine cars. |
| Cinnabar |
A vermilion-colored ore
mineral of mercury. |
| Circulating load |
Over-sized chunks of ore
returned to the head of a closed grinding circuit before going on to the
next stage of treatment. |
| Claim |
A portion of land held either
by a prospector or a mining company. In Canada, the common size is 1,320
ft. (about 400 m) square, or 40 acres (about 16 ha). |
| Clarification |
Process of clearing dirty
water by removing suspended material. |
| Classifier |
A mineral-processing machine
which separates minerals according to size and density. |
| Clay |
A fine-grained material
composed of hydrous aluminum silicates. |
| Cleavage |
The tendency of a mineral to
split along crystallographic planes. |
| Closed circuit |
A loop in the milling process
wherein a selected portion of the product of a machine is returned to
the head of the machine for finishing to required specification. |
| Coal |
A carbonaceous rock mined for
use as a fuel. |
| Coalification |
The metamorphic processes of
forming coal. |
| Collar |
The term applied to the
timbering or concrete around the mouth of a shaft; also used to describe
the top of a mill hole. |
| Column flotation |
A milling process, carried out
in a tall cylindrical column, whereby valuable minerals are separated
from gangue minerals based on their wetability properties. |
| Common stock |
Shares in a company which have
full voting rights which the holders use to control the company in
common with each other. There is no fixed or assured dividend as with
preferred shares, which have first claim on the distribution of a
company's earnings or assets. |
| Complex ore |
An ore containing a number of
minerals of economic value. The term often implies that there are
metallurgical difficulties in liberating and separating the valuable
metals. |
| Cone crusher |
A machine which crushes ore
between a gyrating cone or crushing head and an inverted, truncated cone
known as a bowl. |
| Concentrate |
A fine, powdery product of the
milling process containing a high percentage of valuable metal. |
| Concentrator |
A milling plant that produces
a concentrate of the valuable minerals or metals. Further treatment is
required to recover the pure metal. |
| Confirmation |
A form delivered by a broker
to the client, setting forth the details of stock sales or purchases for
the client. |
| Conglomerate |
A sedimentary rock consisting
of rounded, water-worn pebbles or boulders cemented into a solid mass. |
| Contact |
A geological term used to
describe the line or plane along which two different rock formations
meet. |
| Contact metamorphism |
Metamorphism of country rocks
adjacent to an intrusion, caused by heat from the intrusion. |
| Contango |
A situation in which the price
of a metal for forward or future delivery stands at a premium over the
cash or spot price of the metal. |
| Continuous miner |
A piece of mining equipment
which produces a continuous flow of ore from the working face. |
| Controlled blasting |
Blasting patterns and
sequences designed to achieve a particular objective. Cast blasting,
where the muck pile is cast in a particular direction, and deck
blasting, where holes are loaded once but blasted in successive blasts
days apart, are examples. |
| Converter |
In copper smelting, a furnace
used to separate copper metal from matte. |
| Core |
The long cylindrical piece of
rock, about an inch in diameter, brought to surface by diamond drilling. |
| Core barrel |
That part of a string of tools
in a diamond drill hole in which the core specimen is collected. |
| Cordillera |
The continuous chain of
mountain ranges on the western margin of North and South America. |
| Country rock |
Loosely used to describe the
general mass of rock adjacent to an orebody. Also known as the host
rock. |
| Crosscut |
A horizontal opening driven
from a shaft and (or near) right angles to the strike of a vein or other
orebody. |
| Crust |
The outermost layer of the
Earth; includes both continental and oceanic crust. |
| Cum-dividend |
Buyer entitled to pending
dividend payment. |
| Current assets |
Assets of company which can
and are likely to be converted into cash within a year. Includes cash,
marketable securities, accounts receivable and supplies. |
| Current liabilities |
A company's debts that are
payable within a year's time. |
| Custom smelter |
A smelter which processes
concentrates from independent mines. Concentrates may be purchased or
the smelter may be contracted to do the processing for the independent
company. |
| Cut-and-fill |
A method of stoping in which
ore is removed in slices, or lifts, and then the excavation is filled
with rock or other waste material (backfill), before the subsequent
slice is extracted. |
| Cut value |
Applies to assays that have
been reduced to some arbitrary maximum to prevent erratic high values
from inflating the average. |
| Cyanidation |
A method of extracting exposed
gold or silver grains from crushed or ground ore by dissolving it in a
weak cyanide solution. May be carried out in tanks inside a mill or in
heaps of ore out of doors. |
| Cyanide |
A chemical species containing
carbon and nitrogen used to dissolve gold and silver from ore. |
| Day order |
An order to buy or sell
shares, good only on the day the order was entered. |
| Debenture |
See bonds. |
| Debt financing |
Method of raising capital
whereby companies borrow money from a lending institution. |
| Deck |
The area around the shaft
collar where men and materials enter the cage to be lowered underground. |
| Decline |
A sloping underground opening
for machine access from level to level or from surface; also called a
ramp. |
| Deferred charges |
Expenses incurred but not
charged against the current year's operation. |
| Depletion |
An accounting device, used
primarily in tax computations. It recognizes the consumption of an ore
deposit, a mine's principal asset. |
| Depreciation |
The periodic, systematic
charging to expense of plant assets reflecting the decline in economic
potential of the assets. |
| Development |
Underground work carried out
for the purpose of opening up a mineral deposit. Includes shaft sinking,
crosscutting, drifting and raising. |
| Development drilling |
drilling to establish accurate
estimates of mineral reserves. |
| Diabase |
A common basic igneous rock
usually occurring in dykes or sills. |
| Diamond |
The hardest known mineral,
composed of pure carbon; low-quality diamonds are used to make bits for
diamond drilling in rock. |
| Diamond drill |
A rotary type of rock drill
that cuts a core of rock that is recovered in long cylindrical sections,
two cm or more in diameter. |
| Diamond driller |
A person who operates a
diamond drill. |
| Dilution (mining) |
Rock that is , by necessity,
removed along with the ore in the mining process, subsequently lowering
the grade of the ore. |
| Dilution (of shares) |
A decrease in the value of a
company's shares caused by the issue of treasury shares. |
| Diorite |
An intrusive igneous rock
composed chiefly of sodic plagioclase, hornblende, biotite or pyroxene. |
| Dip |
The angle at which a vein,
structure or rock bed is inclined from the horizontal as measured at
right angles to the strike. |
| Dip needle |
A compass with the needle
mounted so as to swing in a vertical plane, used for prospecting to
determine the magnetic attraction of rocks. |
| Directional drilling |
A method of drilling involving
the use of stabilizers and wedges to direct the orientation of the hole. |
| Discount |
The minimum price below the
par value at which treasury shares may legally be sold. |
| Disseminated ore |
Ore carrying small particles
of valuable minerals spread more or less uniformly through the host
rock. |
| Dividend |
Cash or stock awarded to
preferred and common shareholders at the discretion of the company's
board of directors. |
| Dividend claim |
Made when a dividend has been
paid to the previous holder because stock has not yet been transferred
to the name of the new owner. |
| Dor bar |
The final saleable product of
a gold mine. Usually consisting of gold and silver. |
| Drag fold |
The result of the plastic
deformation of a rock unit where it has been folded or bent back on
itself. |
| Drawpoint |
An underground opening at the
bottom of a stope through which broken ore from the stope is extracted. |
| Drift |
A horizontal underground
opening that follows along the length of a vein or rock formation as
opposed to a crosscut which crosses the rock formation. |
| Drifter |
A hydraulic rock drill used to
drill small-diameter holes for blasting or for installing rock bolts. |
| Drill-indicated reserves |
The size and quality of a
potential orebody as suggested by widely spaced drillholes; more work is
required before reserves can be classified as probable or proven. |
| Dry |
A building where the miner
changes into working clothes. |
| Due diligence |
The degree of care and caution
required before making a decision; loosely, a financial and technical
investigation to determine whether an investment is sound. |
| Dump |
A pile of broken rock or ore
on surface. |
| Dyke |
A long and relatively thin
body of igneous rock that, while in the molten state, intruded a fissure
in older rocks. |
| Electrolysis |
An electric current is passed through a
solution containing dissolved metals, causing the metals to be deposited
onto a cathode. |
| Electrolytic refining |
The process of purifying metal ingots that
are suspended as anodes in an electrolytic bath, alternated with refined
sheets of the same metal which act as starters or cathodes. |
| EM survey |
A geophysical survey method which measures
the electromagnetic properties of rocks. |
| En echelon |
Roughly parallel but staggered structures. |
| Environmental impact study |
A written report, compiled prior to a
production decision, that examines the effects proposed mining
activities will have on the natural surroundings. |
| Epigenetic |
Orebodies formed by hydrothermal fluids and
gases that were introduced into the host rocks from elsewhere, filling
cavities in the host rock. |
| Epithermal deposit |
A mineral deposit consisting of veins and
replacement bodies, usually in volcanic or sedimentary rocks, containing
precious metals or, more rarely, base metals. |
| Equity financing |
The provision of funds by buying shares. |
| Era |
A large division of geologic time, the
Precambrian era, for example |
| Erosion |
The breaking down and subsequent removal of
either rock or surface material by wind, rain, wave action, freezing and
thawing and other processes. |
| Erratic |
Either a piece of visible gold or a large
glacial boulder. |
| Escrowed shares |
Shares deposited in trust pending
fulfilment of certain conditions, and not ordinarily available to
trading until released. |
| Ex-dividend |
On stocks selling "ex-dividend", the seller
retains the right to a pending dividend payment. |
| Exploration |
Prospecting, sampling, mapping, diamond
drilling and other work involved in searching for ore. |
| Face |
The end of a drift, crosscut
or stope in which work is taking place. |
| Fault |
A break in the Earth's crust
caused by tectonic forces which have moved the rock on one side with
respect to the other. |
| Feldspar |
A group of common rock-forming
minerals that includes microcline, orthoclase, plagioclase and others. |
| Felsic |
Term used to describe
light-colored rocks containing feldspar, feldspathoids and silica. |
| Ferrous |
Containing iron. |
| Fine gold |
Fineness is the proportion of
pure gold or silver in jewelry or bullion expressed in parts per
thousand. Thus, 925 fine gold indicates 925 parts out of 1,000, or 92.5%
is pure gold. |
| Fissure |
An extensive crack, break or
fracture in rocks. |
| Fixed Assets |
Possessions such as buildings,
machinery and land which, as opposed to current assets, are unlikely to
be converted into cash during the normal business cycle. |
| Float |
Pieces of rock that have been
broken off and moved from their original location by natural forces such
as frost or glacial action. |
| Flotation |
A milling process in which
valuable mineral particles are induced to become attached to bubbles and
float as others sink. |
| Flowsheet |
An illustration showing the
sequence of operations, step by step, by which ore is treated in a
milling, concentration or smelting process. |
| Flow-through shares |
Shares in an exploration
company that allow the tax deduction or credits for mineral exploration
to be passed to the investor. |
| Flux |
A chemical substance that
reacts with gangue minerals to form slags, which are liquid at furnace
temperature and low enough in density to float on the molten bath of
metal or matte. |
| Fluxgate magnetometer |
An instrument used in
geophysics to measure total magnetic field. |
| Fold |
Any bending or wrinkling of
rock strata. |
| Footwall |
The rock on the underside of a
vein or ore structure. |
| Forward contract |
The sale or purchase of a
commodity for delivery at a specified future date. |
| Fracture |
A break in the rock, the
opening of which allows mineral-bearing solutions to enter. A
"cross-fracture" is a minor break extending at more-or-less right angles
to the direction of the principal fractures. |
| Free milling |
Ores of gold or silver from
which the precious metals can be recovered by concentrating methods
without resorting to pressure leaching or other chemical treatment. |
| Gabbro |
A dark, coarse-grained igneous
rock. |
| Galena |
Lead sulphide, the most common
ore mineral of lead. |
| Gamma |
A unit of measurement of
magnetic intensity. |
| Gangue |
The worthless minerals in an
ore deposit. |
| Geiger counter |
An instrument used to measure
the radioactivity that emanates from certain minerals by means of a
Geiger-Mueller tube. |
| Geochemistry |
The study of the chemical
properties of rocks. |
| Geology |
The science concerned with the
study of the rocks which compose the Earth. |
| Geophysics |
The study of the physical
properties of rocks and minerals. |
| Geophysical survey |
A scientific method of
prospecting that measures the physical properties of rock formations.
Common properties investigated include magnetism, specific gravity,
electrical conductivity and radioactivity. |
| Geothermal |
Pertains to the heat of the
Earth's interior. |
| Glacial drift |
Sedimentary material that has
been transported by glaciers. |
| Glacial striations |
Lines or scratches on a smooth
rock surface caused by glacial abrasion. |
| Glory hole |
An open pit from which ore is
extracted, especially where broken ore is passed to underground workings
before being hoisted. |
| Gneiss |
A layered or banded
crystalline metamorphic rock, the grains of which are aligned or
elongated into a roughly parallel arrangement. |
| Gold loan |
A form of debt financing
whereby a potential gold producer borrows gold from a lending
institution, sells the gold on the open market, uses the cash for mine
development, then pays back the gold from actual mine production. |
| Gossan |
The rust-colored capping or
staining of a mineral deposit, generally formed by the oxidation or
alteration of iron sulphides. |
| Gouge |
Fine, putty-like material
composed of ground-up rock found along a fault. |
| Grab sample |
A sample from a rock outcrop
that is assayed to determine if valuable elements are contained in the
rock. A grab sample is not intended to be representative of the deposit,
and usually the best-looking material is selected. |
| Graben |
A downfaulted block of rock. |
| Granite |
A coarse-grained intrusive
igneous rock consisting of quartz, feldspar and mica. |
| Gravity meter, gravimeter |
An instrument for measuring
the gravitational attraction of the earth; gravitational attraction
varies with the density of the rocks in the vicinity. |
| Greenstone belt |
An area underlain by
metamorphosed volcanic and sedimentary rocks, usually in a continental
shield. |
| Grizzly (or mantle) |
A grating, usually constructed
of steel rails, placed over the top of a chute or ore pass for the
purpose of stopping large pieces of rock or ore that may hang up in the
pass. |
| Gross value |
The theoretical value of ore
determined simply by applying the assay of metal or metals and the
current market price. It must be used only with caution and severe
qualification. |
| Gross value royalty |
A share of gross revenue from
the sale of minerals from a mine. |
| Grouting |
The process of sealing off a
water flow in rocks by forcing a thin slurry of cement or other
chemicals into the crevices; usually done through a diamond drill hole. |
| Grubstake |
Finances or supplies of food,
etc., furnished to a prospector in return for an interest in any
discoveries made. |
| Guides |
The timber rails installed
along the walls of a shaft for steadying, or guiding, the cage or
conveyance. |
| Gypsum |
A sedimentary rock consisting
of hydrated calcium sulphate. |
| Gyratory crusher |
A machine that crushes ore
between an eccentrically mounted crushing cone and a fixed crushing
throat. Typically has a higher capacity than a jaw crusher. |
| Halite |
Rock salt. |
| Hangingwall |
The rock on the upper side of a vein or ore
deposit. |
| Head grade |
The average grade of ore fed into a mill. |
| Heap leaching |
A process whereby valuable metals, usually
gold and silver, are leached from a heap, or pad, of crushed ore by
leaching solutions percolating down through the heap and collected from
a sloping, impermeable liner below the pad. |
| Hedging |
Taking a buy or sell position in a futures
market opposite to a position held in the cash market to minimize the
risk of financial loss from an adverse price change. |
| Hematite |
An oxide of iron, and one of that metal's
most common ore minerals. |
| High grade |
Rich ore. As a verb, it refers to selective
mining of the best ore in a deposit. |
| High-grader |
One who steals rich ore, especially gold,
from a mine. |
| Hoist |
The machine used for raising and lowering
the cage or other conveyance in a shaft. |
| Holding company |
A corporation engaged principally in
holding a controlling interest in one or more other companies. |
| Hornfels |
A fine-grained contact metamorphic rock. |
| Horse |
A mass of waste rock lying within a vein or
orebody. |
| Horst |
An upfaulted block of rock. |
| Host rock |
The rock surrounding an ore deposit. |
| Hydrometallurgy |
The treatment of ore by wet processes, such
as leaching, resulting in the solution of a metal and its subsequent
recovery. |
| Hydrothermal |
Relating to hot fluids circulating in the
earth's crust. |
| Lagging |
Planks or small timbers placed between
steel ribs along the roof of a stope or drift to prevent rocks from
falling, rather than to support the main weight of the overlying rocks. |
| Lamprophyre |
An igneous rock, composed of dark minerals,
that occurs in dykes; sometimes contains diamonds. |
| Laterite |
A residual soil, ususally found in tropical
countries, out of which the silica has been leached. May form orebodies
of iron, nickel, bauxite and manganese. |
| Launder |
A chute or trough for conveying pulp, water
or powdered ore in a mill. |
| Lava |
A general name for the molten rock ejected
by volcanoes. |
| Leachable |
Extractable by chemical solvents. |
| Leaching |
A chemical process for the extraction of
valuable minerals from ore; also, a natural process by which ground
waters dissolve minerals, thus leaving the rock with a smaller
proportion of some of the minerals than it contained originally. |
| Lens |
Generally used to describe a body of ore
that is thick in the middle and tapers towards the ends. |
| Lenticular |
A deposit having roughly the form of a
double convex lens. |
| Level |
The horizontal openings on a working
horizon in a mine; it is customary to work mines from a shaft,
establishing levels at regular intervals, generally about 50 metres or
more apart. |
| Lignite |
A soft, low-rank, brownish-black coal. |
| Limestone |
A bedded, sedimentary deposit consisting
chiefly of calcium carbonate. |
| Limit order |
An order made by a client to a broker to
buy or sell shares at a specified price or better. |
| Limonite |
A brown, hydrous iron oxide. |
| Line cutting |
Straight clearings through the bush to
permit sightings for geophysical and other surveys. |
| Lode |
A mineral deposit in solid rock. |
| Logging |
The process of recording geological
observations of drill core either on paper or on computer disk. |
| London fix |
The twice-daily bidding session held by
five dealing companies to set the gold price. There are also daily
London fixes to set the prices of other precious metals. |
| London Metals Exchange |
A major bidding market for base metals,
which operates daily in London. |
| Long position |
Securities owned outright or carried on
margin. |
| Long ton |
2,240 lbs. avoirdupois (compared with a
short ton, which is 2,000 lbs.). |
| Mafic |
Igneous rocks composed mostly of dark,
iron- and magnesium-rich minerals. |
| Magma |
The molten material deep in the Earth from
which rocks are formed. |
| Magmatic segregation |
An ore-forming process whereby valuable
minerals are concentrated by settling out of a cooling magma. |
| Magnetic gradient survey |
A geophysical survey using a pair of
magnetometers a fixed distance apart, to measure the difference in the
magnetic field with height above the ground. |
| Magnetic separation |
A process in which a magnetically
susceptible mineral is separated from gangue minerals by applying a
strong magnetic field; ores of iron are commonly treated in this way. |
| Magnetic susceptibility |
A measure of the degree to which a rock is
attracted to a magnet. |
| Magnetic survey |
A geophysical survey that measures the
intensity of the Earth's magnetic field. |
| Magnetite |
Black, magnetic iron ore, an iron oxide. |
| Magnetometer |
An instrument used to measure the magnetic
attraction of underlying rocks. |
| Map-staking |
A form of claim-staking practised in some
jurisdictions whereby claims are staked by drawing lines around the
claim on claim maps at a government office. |
| Marble |
A metamorphic rock derived from the
recrystallization of limestone under intense heat and pressure. |
| Margin |
Cash deposited with a broker as partial
payment of the purchase price for any type of listed stock. The stock is
held by the broker as security for the loan. |
| Marginal deposit |
An orebody of minimal profitability. |
| Market order |
An order to buy or sell at the best price
available. In absence of any specified price or limit, an order is
considered to be "at the market". |
| Matte |
A product of a smelter, containing metal
and some sulphur, which must be refined further to obtain pure metal. |
| Metallurgical coal |
Coal used to make steel. |
| Metallurgy |
The study of extracting metals from their
ores. |
| Metamorphic rocks |
Rocks which have undergone a change in
texture or composition as the result of heat and/or pressure. |
| Metamorphism |
The process by which the form or structure
of rocks is changed by heat and pressure. |
| Migmatite |
Rock consisting of thin, alternating layers
of granite and schist. |
| Mill |
A plant in which ore is treated and metals
are recovered or prepared for smelting; also a revolving drum used for
the grinding of ores in preparation for treatment. |
| Milling ore |
Ore that contains sufficient valuable
mineral to be treated by milling process. |
| Millivolts |
A measure of the voltage of an electric
current, specifically, one-thousandth of a volt. |
| Minable reserves |
Ore reserves that are known to be
extractable using a given mining plan. |
| Mineral |
A naturally occurring homogeneous substance
having definite physical properties and chemical composition and, if
formed under favorable conditions, a definite crystal form. |
| Mining MarketWatch |
MiningMarketWatch.com is your ultimate
source for mining information. |
| Muck |
Ore or rock that has been broken by
blasting. |
| Muck sample |
A representative piece of ore that is taken
from a muck pile and then assayed to determine the grade of the pile. |
| Odd lot |
A block of shares that is less
than a board lot. |
| Open order |
An order to buy or sell stock,
which is good until cancelled by the client. |
| Open pit |
A mine that is entirely on
surface. Also referred to as open-cut or open-cast mine. |
| Option |
An agreement to purchase a
property reached between the property vendor and some other party who
wishes to explore the property further. |
| Option (on stock) |
The right to buy or sell a
share at a set price, regardless of market value. |
| Ore |
A mixture of ore minerals and
gangue from which at least one of the metals can be extracted at a
profit. |
| Ore pass |
Vertical or inclined passage
for the downward transfer of ore connecting a level with the hoisting
shaft or a lower level. |
| Orebody |
A natural concentration of
valuable material that can be extracted and sold at a profit. |
| Ore Reserves |
The calculated tonnage and
grade of mineralization which can be extracted profitably; classified as
possible, probable and proven according to the level of confidence that
can be placed in the data. |
| Oreshoot |
The portion, or length, of a
vein or other structure that carries sufficient valuable minerals to be
extracted profitably. |
| Organic maturation |
The process of turning peat
into coal. |
| Orogeny |
A period of mountain-building
characterized by the folding of a portion of the earth's crust. |
| Outcrop |
An exposure of rock or mineral
deposit that can be seen on surface, that is, not covered by soil or
water. |
| Overturned |
Where the oldest sedimentary
rock beds are lying on top of a younger beds. |
| Oxidation |
A chemical reaction caused by
exposure to oxygen that results in a change in the chemical composition
of a mineral. |
| Pan |
To wash gravel, sand or
crushed rock samples in order to isolate gold or other valuable metals
by their higher density. |
| Participating interest |
A company's interest in a
mine, which entitles it to a certain percentage of profits in return for
putting up an equal percentage of the capital cost of the project. |
| Par value |
The stated face value of a
stock. Par value shares have no specified face value, but the total
amount of authorized capital is set down in the company's charter. |
| Patent |
The ultimate stage of holding
a mineral claim, after which no more assessment work is necessary
because all mineral rights have been earned. |
| Pegmatite |
A coarse-grained, igneous
rock, generally coarse, but irregular in texture, and similar to a
granite in composition; usually occurs in dykes or veins and sometimes
contains valuable minerals. |
| Pellet |
A marble-sized ball of iron
ore fused with clay for transportation and use in steelmaking. |
| Pentlandite |
Nickel iron sulphide, the most
common nickel ore. |
| Peridotite |
An intrusive igneous rock
consisting mainly of olivine. |
| Phaneritic |
A term used to describe the
coarse-grained texture of some igneous rocks. |
| Picket line |
A reference line, marked by
pickets or stakes, established on a property for mapping and survey
purposes. |
| Pig iron |
Crude iron from a blast
furnace. |
| Pillar |
A block of solid ore or other
rock left in place to structurally support the shaft, walls or roof of a
mine. |
| Pitchblende |
An important uranium ore
mineral. It is black in color, possesses a characteristic greasy lustre
and is highly radioactive. |
| Placer |
A deposit of sand and gravel
containing valuable metals such as gold, tin or diamonds. |
| Plant |
A building or group of
buildings in which a process or function is carried out; at a mine site
it will include warehouses, hoisting equipment, compressors, maintenance
shops, offices and the mill or concentrator. |
| Plate tectonics |
A geological theory which
postulates that the Earth's crust is made up of a number of rigid plates
which collide, rub up against and spread out from one another. |
| Plug |
A common name for a small
offshoot from a large body of molten rock. |
| Plunge |
The vertical angle a linear
geological feature makes with the horizontal plane. |
| Plutonic |
Refers to rocks of igneous
origin that have come from great depth. |
| Point |
Unit of value of a stock as
quoted by a stock exchange. May represent one dollar, one cent or
one-eighth of a dollar, depending on the stock exchange. |
| Polishing pond |
The last in a series of
settling ponds through which mill effluent flows before being discharged
into the natural environment. |
| Pooling shares |
See escrowed shares. |
| Porphyry |
Any igneous rock in which
relatively large crystals , called phenocrysts, are set in a
fine-grained groundmass. |
| Porphyry copper |
A deposit of disseminated
copper minerals in or around a large body of intrusive rock. |
| Portal |
The surface entrance to a
tunnel or adit. |
| Portfolio |
A list of financial assets. |
| Possible reserves |
Valuable mineralization not
sampled enough to accurately estimate its tonnage and grade, or even
verify its existence. Also called "inferred reserves." |
| Potash |
Potassium compounds mined for
fertilizer and for use in the chemical industry. |
| Precambrian Shield |
The oldest, most stable
regions of the earth's crust, the largest of which is the Canadian
Shield. |
| Preferred shares |
Shares of a limited liability
company that rank ahead of common shares, but after bonds, in
distribution of earnings or in claim to the company's assets in the
event of liquidation. They pay a fixed dividend but normally do not have
voting rights, as with common shares. |
| Price-to-earnings ratio |
The current market price of a
stock divided by the company's net earnings per share for the year. |
| Primary deposits |
Valuable minerals deposited
during the original period or periods of mineralization, as opposed to
those deposited as a result of alteration or weathering. |
| Private placement |
Sale of shares to individuals
or corporations outside the normal market, at a negotiated price. Often
used to raise capital for a junior exploration company. |
| Pro rata |
In proportion, usually to
ownership, income or contribution. |
| Probable reserves |
Valuable mineralization not
sampled enough to accurately estimate the terms of tonnage and grade.
Also called "indicated reserves." |
| Profit and loss statement |
The income statement of a
company detailing revenues minus total costs to give total profit. |
| Prospect |
A mining property, the value
of which has not been determined by exploration. |
| Prospectus |
A document filed with the
appropriate securities commission detailing the activities and financial
condition of a company seeking funds from the public through the
issuance of shares. |
| Proton precession magnetometer |
A geophysical instrument which
measures magnetic field intensity in terms of vertical gradient and
total field. |
| Proven reserves |
Reserves that have been
sampled extensively by closely spaced diamond drill holes and developed
by underground workings in sufficient detail to render an accurate
estimation of grade and tonnage. Also called "measured reserves." |
| Proxy |
A power of attorney given by
the shareholder so that his stock may be voted by his nominee(s) at
shareholders' meetings. |
| Pulp |
Pulverized or ground ore in
solution. |
| Put |
An option to sell a stock at
an agreed upon price within a specified time. The owner can present his
put to the contracting broker at any time within the option period and
compel him to buy the stock. |
| Pyramiding |
The use of increased buying
power to increase ownership arising from price appreciation. |
| Pyrite |
A yellow iron sulphide
mineral, normally of little value. It is sometimes referred to as
"fool's gold". |
| Pyrrhotite |
A bronze-colored, magnetic
iron sulphide mineral. |
| Radioactivity |
The property of spontaneously
emitting alpha, beta or gamma rays by the decay of the nuclei of atoms. |
| Radon survey |
A geochemical survey technique
which detects traces of radon gas, a product of radioactivity. |
| Raise |
A vertical or inclined
underground working that has been excavated from the bottom upward. |
| Rake |
The trend of an orebody along
the direction of its strike. |
| Rare earth elements |
Relatively scarce minerals
such as niobium and yttrium. |
| Reaming shell |
A component of a string of
rods used in diamond drilling, it is set with diamonds and placed
between the bit and the core barrel to maintain the gauge (or diameter)
of the hole. |
| Reclamation |
The restoration of a site
after mining or exploration activity is completed. |
| Reconnaissance |
A preliminary survey of
ground. |
| Record date |
The date by which a
shareholder must be registered on the books of a company in order to
receive a declared dividend, or to vote on company affairs. |
| Recovery |
The percentage of valuable
metal in the ore that is recovered by metallurgical treatment. |
| Refractory ore |
Ore that resists the action of
chemical reagents in the normal treatment processes and which may
require pressure leaching or other means to effect the full recovery of
the valuable minerals. |
| Regional metamorphism |
Metamorphism caused by both
the heat of igneous processes and tectonic pressure. |
| Replacement ore |
Ore formed by a process during
which certain minerals have passed into solution and have been carried
away, while valuable minerals from the solution have been deposited in
the place of those removed. |
| Resistivity survey |
A geophysical technique used
to measure the resistance of a rock formation to an electric current. |
| Resource |
The calculated amount of
material in a mineral deposit, based on limited drill information. |
| Resuing |
A method of stoping in
narrow-vein deposits whereby the wallrock on one side of the vein is
blasted first and then the ore. |
| Reverberatory furnace |
A long, flat furnace used to
slag gangue minerals and produce a matte. |
| Rhyolite |
A fine-grained, extrusive
igneous rock which has the same chemical composition as granite. |
| Rib samples |
Ore taken from rib pillars in
a mine to determine metal content. |
| Rights |
In finance, a certified right
to purchase treasury shares in stated quantities, prices and time
limits; usually negotiable at a price which is related to the prices of
the issue represented; also referred to as warrants. Rights and warrants
can be bought and sold prior to their expiry date because not all
shareholders wish to exercise their rights. |
| Rock |
Any natural combination of
minerals; part of the earth's crust. |
| Rockbolting |
The act of supporting openings
in rock with steel bolts anchored in holes drilled especially for this
purpose. |
| Rockburst |
A violent release of energy
resulting in the sudden failure of walls or pillars in a mine, caused by
the weight or pressure of the surrounding rocks. |
| Rock factor |
The number of cubic metres of
a particular rock type required to make up one tonne of the material.
One tonne of a highly siliceous ore may occupy 0.40 cubic metres, while
a tonne of dense sulphide ore may occupy only 0.25 cubic metres. |
| Rock mechanics |
The study of the mechanical
properties of rocks, which includes stress conditions around mine
openings and the ability of rocks and underground structures to
withstand these stresses. |
| Rod mill |
A rotating steel cylinder that
uses steel rods as a means of grinding ore. |
| Room-and-pillar mining |
A method of mining flat-lying
ore deposits in which the mined-out area, or rooms, are separated by
pillars of approximately the same size. |
| Rotary drill |
A machine that drills holes by
rotating a rigid, tubular string of drill rods to which is attached a
bit. Commonly used for drilling large-diameter blastholes in open-pit
mines. |
| Royalty |
An amount of money paid at
regular intervals by the lessee or operator of an exploration or mining
property to the owner of the ground. Generally based on a certain amount
per tonne or a percentage of the total production or profits. Also, the
fee paid for the right to use a patented process. |
| Run-of-mine |
A term used loosely to
describe ore of average grade. |
| Salting |
The act of introducing metals or minerals
into a deposit or samples, resulting in false assays. Done either by
accident or with the intent of defrauding the public. |
| Sample |
A small portion of rock or a mineral
deposit taken so that the metal content can be determined by assaying. |
| Sampling |
Selecting a fractional but representative
part of a mineral deposit for analysis. |
| Sandstone |
A sedimentary rock consisting of grains of
sand cemented together. |
| Scaling |
The act of removing loose slabs of rock
from the back and walls of an underground opening, usually done with a
hand-held scaling bar or with a boom-mounted scaling hammer. |
| Scarp |
An escarpment, cliff or steep slope along
the margin of a plateau, mesa or terrace. |
| Schist |
A foliated metamorphic rock the grains of
which have a roughly parallel arrangement; generally developed by
shearing. |
| Scintillation counter |
An instrument used to detect and measure
radioactivity by detecting gamma rays; more sensitive than a geiger
counter. |
| Secondary enrichment |
Enrichment of a vein or mineral deposit by
minerals that have been taken into solution from one part of the vein or
adjacent rocks and redeposited in another. |
| Sedimentary rocks |
Secondary rocks formed from material
derived from other rocks and laid down under water. Examples are
limestone, shale and sandstone. |
| Seismic prospecting |
A geophysical method of prospecting,
utilizing knowledge of the speed of reflected sound waves in rock. |
| Self-potential |
A technique, used in geophysical
prospecting, which recognizes and measures the minute electric currents
generated by sulphide deposits. |
| Semi-autogenous grinding (SAG) |
A method of grinding rock into fine powder
whereby the grinding media consist of larger chunks of rocks and steel
balls. |
| Serpentine |
A greenish, metamorphic mineral consisting
of magnesium silicate. |
| Shaft |
A vertical or inclined excavation in rock
for the purpose of providing access to an orebody. Usually equipped with
a hoist at the top, which lowers and raises a conveyance for handling
workers and materials. |
| Shale |
Sedimentary rock formed by the
consolidation of mud or silt. |
| Shear or shearing |
The deformation of rocks by lateral
movement along innumerable parallel planes, generally resulting from
pressure and producing such metamorphic structures as cleavage and
schistosity. |
| Shear zone |
A zone in which shearing has occurred on a
large scale. |
| Sheave wheel |
A large, grooved wheel in the top of a
headframe over which the hoisting rope passes. |
| Shoot |
A concentration of mineral values; that
part of a vein or zone carrying values of ore grade. |
| Short selling |
The borrowing of stock from a broker in
order to sell it in the hope that it may be purchased at a lower price
later on. |
| Short ton |
2,000 lbs. avoirdupois. |
| Shrinkage stoping |
A stoping method which uses part of the
broken ore as a working platform and as support for the walls of the
stope. |
| Siderite |
Iron carbonate, which when pure, contains
48.2% iron; must be roasted to drive off carbon dioxide before it can be
used in a blast furnace. Roasted product is called sinter. |
| Silica |
Silicon dioxide. Quartz is a common
example. |
| Siliceous |
A rock containing an abundance of quartz. |
| Sill |
An intrusive sheet of igneous rock of
roughly uniform thickness that has been forced between the bedding
planes of existing rock. |
| Silt |
Muddy deposits of fine sediment usually
found on the bottoms of lakes. |
| Sinter |
Fine particles of iron ore that have been
treated by heat to produce blast furnace feed. |
| Skarn |
Name for the metamorphic rocks surrounding
an igneous intrusive where it comes in contact with a limestone or
dolostone formation. |
| Skip |
A self-dumping bucket used in a shaft for
hoisting ore or rock. |
| Slag |
The vitreous mass separated from the fused
metals in the smelting process. |
| Slash |
The process of blasting rock from the side
of an underground opening to widen the opening. |
| Slate |
A metamorphic rock; the metamorphic
equivalent of shale. |
| Slickenside |
The striated, polished surface of a fault
caused by one wall rubbing against the other. |
| Sludge |
Rock cuttings from a diamond drill hole,
sometimes used for assaying. |
| Sodium cyanide |
A chemical used in the milling of gold ores
to dissolve gold and silver. |
| Solvent extraction-electrowinning (SX-EW) |
A metallurgical technique, so far applied
only to copper ores, in which metal is dissolved from the rock by
organic solvents and recovered from solution by electrolysis. |
| Spelter |
The zinc of commerce, more or less impure,
cast from molten metal into slabs or ingots. |
| Sphalerite |
A zinc sulphide mineral; the most common
ore mineral of zinc. |
| Split |
The shareholder-approved division of a
company's outstanding common shares into a larger number of new common
shares. |
| Spot price |
Current delivery price of a commodity
traded in the spot market. |
| Station |
An enlargement of a shaft made for the
storage and handling of equipment and for driving drifts at that
elevation. |
| Step-out drilling |
Holes drilled to intersect a mineralization
horizon or structure along strike or down dip. |
| Stock exchange |
An organized market concerned with the
buying and selling of common and preferred shares and warrants by
stockbrokers who own seats on the exchange and meet membership
requirements. |
| Stockpile |
Broken ore heaped on surface, pending
treatment or shipment. |
| Stope |
An excavation in a mine from which ore is,
or has been, extracted. |
| Stop-loss order |
An arrangement whereby a client gives his
broker instructions to sell a stock if and when its price drops to a
specified figure on the market. |
| Stratigraphy |
Strictly, the description of bedded rock
sequences; used loosely, the sequence of bedded rocks in a particular
area. |
| Streak |
A diagnostic characteristic of minerals,
where scratching a sample on a piece of unglazed porcelain leaves powder
of a characteristic color. |
| Street certificate |
A certificate representing ownership in a
specified number of shares that is registered in the name of some
previous owner who has endorsed the certificate so that it may be
transferred to a new owner without referral to transfer agent. |
| Striations |
Prominent parallel scratches left on
bedrock by advancing glaciers. |
| Strike |
The direction, or bearing from true north,
of a vein or rock formation measure |
| on a horizontal surface. |
| Stringer |
A narrow vein or irregular filament of a
mineral or minerals traversing a rock mass. |
| Strip |
To remove the overburden or waste rock
overlying an orebody in preparation for mining by open pit methods. |
| Stripping ratio |
The ratio of tonnes removed as waste
relative to the number of tonnes of ore removed from an open-pit mine. |
| Strip mine |
An open-pit mine, usually a coal mine,
operated by removing overburden, excavating the coal seam, then
returning the overburden. |
| Sub-bituminous |
A black coal, intermediate between lignite
and bituminous. |
| Sublevel |
A level or working horizon in a mine
between main working levels. |
| Subsidiary company |
A company in which the majority of shares
(a controlling position) is held by another company. |
| Sulphide |
A compound of sulphur and some other
element. |
| Sulphide dust explosions |
An underground mining hazard involving the
spontaneous combustion of airborne dust containing sulphide minerals. |
| Sulphur dioxide |
A gas liberated during the smelting of most
sulphide ores; either converted into sulphuric acid or released into the
atmosphere in the form of a gas. |
| Sump |
An underground excavation where water
accumulates before being pumped to surface. |
| Sustainable development |
Industrial development that does not
detract from the potential of the natural environment to provide
benefits to future generations. |
| Syenite |
An intrusive igneous rock composed chiefly
of orthoclase. |
| Sylvite |
potassium chloride, the principal ore of
potassium mined for fertilizer manufacturing. |
| Syncline |
A down-arching fold in bedded rocks. |
| Syngenetic |
A term used to describe when mineralization
in a deposit was formed relative to the host rocks in which it is found.
In this case, the mineralization was formed at the same time as the host
rocks. (The opposite is epigenetic.) |
| Taconite |
A highly abrasive iron ore. |
| Tailings |
Material rejected from a mill after most of
the recoverable valuable minerals have been extracted. |
| Tailings pond |
A low-lying depression used to confine
tailings, the prime function of which is to allow enough time for heavy
metals to settle out or for cyanide to be destroyed before water is
discharged into the local watershed. |
| Talus |
A heap of broken, coarse rock found at the
base of a cliff or mountain. |
| Telluride |
A chemical compound consisting of the
element tellurium and another element, often gold or silver. |
| Thermal coal |
Coal burned to generate the steam that
drives turbines to generate electricity. |
| Thickener |
A large, round tank used in milling
operations to separate solids from liquids; clear fluid overflows from
the tank and rock particles sink to the bottom. |
| Tonnes-per-vertical-metre |
Common unit used to describe the amount of
ore in a deposit; ore length is multiplied by the width and divided by
the appropriate rock factor to give the amount of ore for each vertical
metre of depth. |
| Trading floor |
the area of a stock exchange building where
shares are bought and sold. |
| Trading post |
An area on the trading floor of a stock
exchange where current stock prices are listed and where the floor
traders (representatives of brokerage firms) meet to buy or sell the
stocks listed at that particular post. |
| Tram |
To haul cars of ore or waste in a mine. |
| Treasury shares |
The unissued shares in a company's
treasury. |
| Trench |
A long, narrow excavation dug through
overburden, or blasted out of rock, to expose a vein or ore structure. |
| Trend |
The direction, in the horizontal plane, of
a linear geological feature, such as an ore zone, measured from true
north. |
| Tube mill |
An apparatus consisting of a revolving
cylinder about half-filled with steel rods or balls and into which
crushed ore is fed for fine grinding. |
| Tuff |
Rock composed of fine volcanic ash. |
| Tunnel |
A horizontal underground opening, open to
the atmosphere at both ends. |
| Tunnel-boring-machine |
A machine used to excavate a tunnel through
soil or rock by mechanical means as opposed to drilling and blasting. |
