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GLOSSARY OF TERMS
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Select
the first letter of the word from the list above
to jump to appropriate section of the glossary.
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A -
Abrasion:
Wearing away or erosion by friction.
Abrasive: Substance used to grind or polish
other materials.
Absorb: The sucking up or retention of liquid
by a solid.
Absorption: The act of being absorbed, as
water in a sponge.
Accretion: The accumulation of material by
physical or chemical means.
Acicular: Slender and straight, such as needle-shaped
crystals.
Acid: A salt or dissolved compound of hydrogen
wherein one or more atoms of hydrogen may be displaced
by a metal ion.
Acidic: Characterized by a predominance of
acid-forming minerals.
Acre-foot: Amount of water that will cover
1 acre to a depth of 1 foot.
Acre: A unit of land measure equal to 43,560
square feet.
Adamantine: Having a diamond-like luster
or hardness.
Adhere: To stick to an unlike substance.
Adhesion: The sticking together of two or
more unlike substances.
Adit: A tunnel driven horizontally into the
side of a mountain or hill to gain access to mineral
deposits for exploration or mining.
Adjusted value: An analytical result that
has been increased or decreased by an amount necessary
to compensate for known, or suspected, variables
in sampling analyses. Also called "corrected
value".
Adobe: A general term for several types of
sticky clays; also used to describe dried bricks
of clay and straw, and buildings made of same.
Adsorb: The physical or chemical sticking
of dissolved substances to the surface of solid
materials.
Adsorption: The process of being adsorbed,
as in the absorption of precious metals on activated
carbon.
Aerial: Airborne or suspended in air.
Afterdamp: Unbreathable gases remaining after
an underground explosion.
Agate: A waxy variety of chalcedony or quartz,
a semiprecious stone.
Agglomerate: To gather or form into a rounded
mass; also type of breccia.
Agglomeration: Forming crushed ores into
pellets by mixing with concrete.
Aggregate: Common term for gravels; also
to gather or bring together.
Ainlay bowl: A wet gravity concentrator used
to revolve heavy placer minerals by centrifugal
force.
Airplane drill: A light and compact engine
powered placer drill designed for use in areas that
are difficult to access.
Alignment: Lining-up or adjusting to a standard.
Alkali: Whitish, crusted salts on soils created
by evaporation; also basic salt containing calcium,
sodium or potassium, etc.
Alliaceous: Mineral having a garlic-like
odor; arsenical compounds.
Allotropy: The ability of some minerals to
exist in two or more forms.
Alloy: A solid mixture or combination of
two or more metals.
Alluvial: Pertaining to soil and gravel deposited
by water action; related to gravels, silt and mud
formed and deposited by water movement.
Alumina: A mineral composed primarily of
aluminum oxides.
Amalgam: An alloy or union of mercury with
another metal: gold or other metal that has been
coated with mercury by adhesion.
Amalgamation: Removing precious metals from
ores by use of mercury.
Amorphous: Without definite form; no crystalline
structure.
Analysis: The determination of the contents
in any substance.
Anhydrous: Refers to compounds having no
water in their composition.
Anneal: Heating and cooling metals to make
them harder and stronger. Annual labor: Yearly assessment
work on unpatented mining claims.
Anticline: An elevated fold in rock strata,
such as a ridge.
Apex: The highest point of anything, such
as a vein, outcrop or hill.
Aqua Regia: Acid mixture of 3 parts hydrochloric
and 1 part nitric acid.
Aqueous: Containing water or related to material
deposited by water.
Aquifer: A rock formation or basin containing
water.
Arbitrage: To simultaneously buy and sell
a commodity or security in different markets to
take advantage of price differentials.
Arborescent: Minerals that branch in treelike
forms.
Archean: Refers to rock group of the Archean
geological era.
Argentiferous: Pertains to silver-bearing
rocks.
Argillaceous: Consisting of clay or having
a clayey nature.
Arrastra: Crude stone mill for grinding and
amalgamating gold ores.
Arsenical: Pertaining to or containing arsenic.
Assay Value: The value of an ore as determined
by assay results; the amount and worth of metals
or minerals in a sample.
Assay-ton: Assaying equivalent ton, equal
to 29.166 grams.
Assay: The determination of the type and
quantity of metals or minerals in an ore; an analytical
determination of the metal or mineral content in
a sample. To chemically test the purity of metal.
Also refers to the lab procedure and final result.
Assessment Work: Annual work on unpatented
claims required by mining law.
Atomic Weight: The relative weight of an
atom of an element as compared to the most stable
isotope of carbon (At. Wt.12.01115).
At-the-Money: An option whose strike price
is equal, or approximately equal, to the current
market price of the underlying futures contract.
Attrition: Loss of material through friction
and abrasion.
Auriferous: Refers to gold-bearing rocks
and gravels.
Autoclave system: Oxidation process in which
high temperatures and pressures are applied to convert
refractory sulphide mineralization into amenable
oxide ore.
Avoirdupois: Common system of weights used
in the U.S. and Britain.
Axis: The centerline of a crystal, object
or rotating shaft.
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B -
Backfill:
Replacing material removed from an excavation.
Backfilling: Waste material used to fill
the void created by mining an ore body.
Backwardation: A market situation in which
prices are progressively lower in future months
than in the nearest month. A backwardation market
generally reflects a near-term shortage of commodity,
hence the premium price for current delivery.
Backwash: Water movement against the primary
direction of flow.
Badlands: A barren or extremely rough terrain.
Baffle: A partition or grating in a furnace,
container or channel.
Bailer: Device for removing sludge and water
from a drill hole or mine.
Ball mill: A steel cylinder loaded with steel
balls into which crushed ore is fed. The ball mill
is rotated, causing the balls to cascade and grind
the ore.
Banded: Pertains to layered rocks or rock
formations.
Bar: A metal rod with chiseled end used for
prying; also refers to an accumulation of gravel
in watercourse.
Basalt: General term for all dark-colored
volcanic rocks.
Base metal: Any common useful metal, excepting
the precious metals.
Base: Any compound that will combine with
an acid and neutralize it, forming a salt: also
bottom or support for any structure.
Basic: Underlying fundamental; rocks with
little silica; also the opposite of acidic.
Basis: The difference between the spot or
cash price of a commodity. Basis is calculated to
the nearby position and may represent different
time periods, product forms, grades and locations,
depending on the cash and futures prices used.
Batholith: A large mass of igneous rock extending
to a great depth.
Bear Market: A market in which prices are
declining.
Bedded: Refers to rock formations deposited
in successive layers.
Bedrock: Solid rock beneath topsoils and
gravel deposits.
Benches: Natural or man-made step-like terraces.
Bid: A proposal to buy a specific quantity
of a metal or a futures contract at a given price;
opposite of offer.
Bid/Ask: Bid (or buy) is the price a dealer
will pay for gold bullion or coins. Ask (or sell)
is the selling price offered by a dealer.
Bit: The hardened cutting end that attaches
to drill rod.
Black gold: Placer gold that is coated with
black manganese oxides.
Blast hole: A hole drilled for emplacement
of explosives.
Blasting: Detonating explosives to loosen
rock for excavation.
Boiling Point: The point at which a substance
boils; for water, 212 degrees F. or 100 degrees
C.
Borehole: Common term for a drill hole.
Borer: Common term for rock-cutting drill.
Bort: An impure diamond used for hardening
drill bits; an abrasive.
Bortryoidal: Refers to mineral occurring
in globular forms.
Brace: Mine timber; also platform over mouth
of vertical shaft.
Breaker: Slang term for a rock crusher.
Breast: The working face of a placer drift,
normally underground.
Breccia: An altered rock composed of angular
fragments cemented together in a matrix material.
Brittle: Easily fractured or broken.
Bucket line dredge: A large dredge that utilizes
a chain of buckets to excavate and lift gravels
for processing.
Bulkhead: Partition erected to seal off certain
portions of mines.
Bulldozing: Moving material with mechanized
equipment.
Bullion: Precious metals in the form of bars,
wafers, or ingots of .995 purity or finer. Also
called "dore" or "zoo".
Bull Market: A market in which prices are
rising.
Butte: An isolated hill or mountain with
steep sides.
Button: Refers to precious metal globule
produced by fire assaying.
By-product: A secondary product, usually
another mineral recovered in the mining and processing
of the primary mineral.
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C -
Cache:
A place where supplies are stored or hidden.
Caisson: A metal casing or cylinder used to
sink shafts in unstable or wet placer ground.
Calcareous: Like limestone or calcium carbonate,
or composed of same.
Calcine: To roast a substance and drive of
its volatile contents.
Calich: A cemented conglomerate, usually occurring
in desert climates.
Calorie: Heat required to raise the temperature
of 1 gram of water by 1 degree Centigrade.
Cam: Projection on a shaft that impart irregular
motion or reciprocating action to another part; also
the shaft itself.
Cap rock: A layer of rock lying on top of another
type of rock.
Capillarity: The property of liquids allowing
them to rise through solids.
Carat: Unit of weight used for precious stones,
equal to 3.2 grains.
Carbon-in-leach: A recovery process in which
a slurry of gold ore, carbon granules and cyanide
are mixed together. The cyanide dissolves the gold
content and the gold is adsorbed on the carbon. The
carbon is subsequently separated from the slurry for
further gold removal.
Carbon-in-pulp: Similar to carbon-in-leach
process, but initially the slurry is subjected to
cyanide leaching in separate tanks followed by carbon-in-pulp.
Carbon-in-pulp is a sequential process whereas carbon-in-leach
is a simultaneous process.
Carbon Steel: A steel hardened by the addition
of carbon; drill rod.
Carbonaceous: Refers to rocks interning carbon.
Carboniferous: A geological time period.
Carborundum: Silicon carbide used as an abrasive.
Carrying Charge: The cost of storing metal
over a period of time. Includes insurance, storage,
and interest on the invested funds.
Cash and Carry: In a contango market, the premium
of the forward position over the nearby position generally
reflects the cost of storage, insurance and finance
for that period. When metal is in surplus, the contango
may widen to the point where banking operations are
attractive. Capital is invested by buying cash metal
and simultaneously selling forward. A positive cash
and carry yields, after costs, a better return than
prevailing money markets.
Cash Market or Price: The physical commodity
or the price required for immediate settlement. In
futures, the nearest delivery month. Also known as
the "spot price."
Casing head: Hardened fitting on top of casing,
used for driving casing.
Casing: Pipe inserted into water wells and
certain drill holes.
Caustic: Corrosive chemical substance.
Cave In: Collapse of mine workings.
Caving: A mining method where ore is purposely
caved.
Centigrade: A system for measuring temperature.
Ceramic: Refers to clays hardened by roasting.
Chain: Survey measure equal to 66 feet.
Channel: The main section of a water course.
Check valve: Device for controlling flow of
liquids or gasses.
Chemical Analysis: Determination of content
by chemistry.
Chemical: Refers to substances involved in
reaction between the elements.
Clearing: The procedure through which trades
are checked for accuracy after which the clearinghouse
becomes the buyer to each seller and the seller to
each buyer.
Clearinghouse: An agency connected to a commodity
exchange through which transactions executed on the
floor of the exchange are cleared.
Coarse gold: General term applied to rough
or angular gold particles as well as to larger pieces
or nuggets.
Collar: The term applied to the timbering or
concrete around the mouth of a shaft and the start
of a drill hole.
Colloidal gold: Extremely fine gold particles
that can remain suspended in solution.
Concentrate: To separate and enrich the valuable
minerals contained in the placer, and also the product
of that concentration.
Concentrate: A powdery product containing the
valuable ore mineral from which most of the waste
material has been eliminated.
Conglomerate: An aggregate of sand and gravel
that has been cemented together by other mineral substances.
Contained ounces: Represents ounces in the
ground without the reduction of ounces not recovered
by the applicable metallurgical process.
Contango: A market condition in which prices
are progressively higher in future months than in
the nearest delivery month. A contango market generally
reflects ample supplies of a commodity. The actual
difference between spot and forward prices is also
called the contango, which is primarily the cost of
money to finance metal over time.
Convergence: A natural decline in the differential
between the cash and the nearby futures price to the
point where both reach or approach zero.
Cradle: Refers to a gold rocker.
Crevicing: The cleaning of cracks and crevices
in the bedrock beneath a watercourse for the gold
particles lodged therein. Also called "sniping".
Cribbing: Timbering used to support shafts
in wet or loose gravels.
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 mined.
Cutoff Grade: The minimum grade of ore that
can be mined and processed economically.
Cyanidation: A method of extracting gold or
silver by dissolving it in a weak solution of sodium
cyanide.
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D -
Dedicated
Pad: See Leach Pad.
Delivery: The tender and receipt of actual
metal or warehouse receipt in settlement of a futures
contract.
Detritus: A general term covering all unconsolidated
sediments.
Development: Underground work carried out for
the purpose of opening up a mineral deposit. Includes
shaft sinking, crosscutting, drifting and raising.
Dilution: The unwanted but unavoidable inclusion
of some barren or low-grade rock along with the ore
being mined. This lowers the grade of the mined material.
Dome: An uplifted structure with an inverted
bowl shape.
Dore: An unrefined bar of bullion containing
an alloy of gold, silver and impurities. Dore bars
are typically shipped to outside refiners for further
processing, then sold to precious metals dealers,
mainly banks and their affiliates.
Dragline: Equipment with a long boom and large
digging bucket that is cast outward and dragged back
toward the machine.
Drift: A horizontal tunnel driven alongside
an ore deposit, from either an adit or shaft, to gain
access to the deposit. Any horizontal tunnel or cut
in underground mines.
Drill core: The sand and gravel forced upward
into the drill casing as it is driven into placer
deposit.
Drill lug: A record of drilling results compiled
as the work progresses.
Drilling
Blatsthole Drilling: The drilling of holes
in rock to insert an explosive charge. The drill holes
are usually about 10-25 feet apart. The ensuing synchronized
blast will break up the rock so it can be dug out.
Diamond (or Core) Drilling: Drilling with a
hollow diamond studded bit to cut out a solid rock
core. A column of rock is extracted from inside the
drill rod for geological examination and assay.
In-Fill Drilling: Drilling between widely spaced
holes (typically up to 200 feet apart) to establish
or upgrade the ore reserve classification.
Rotary Drilling: Drilling with a bit that breaks
the rock into chips. The chips are continually flushed
up the hole (outside the drill pipe) and are collected
in sequence for geological examination and assay.
Reverse-Circulation Drilling: A type of Rotary
Drilling that uses a double-walled drill pipe. Compressed
air, water or other drilling medium is forced down
the space between the two pipes to the drill bit,
and the drilled chips are flushed back up to the surface
through the center tube of the drill pipe.
Step-Out Drilling: Drilling at widely spaced
intervals (typically in increments of 300 feet) outward
from known deposits to test for extensions of mineralization.
Drive pile: Another term for casing.
Dry washing: Extracting gold from dry gravels,
usually by equipment which uses air bellows for separating
lighter from heavier material.
Ductile: Capable of being bent, drawn into
wire, or pounded into sheets.
Dull: Refers to a mineral's luster; not colorful
or shiny.
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E -
Effervesce:
Forming and breaking gas bubbles by chemical reaction.
Electrostatic separator: Machine employing
static electrical charges to separate heavy mineral
concentrates.
Electrum: Native gold containing a large amount
of alloyed silver.
Element: Substance composed of atoms that cannot
be broken down by ordinary chemical means; metals,
nonmetals and certain gases.
Eluvium: Material produced by decomposing rock
formations where water movement and abrasion are not
present.
Emulsion: A mixture of water and oily substances.
End line: Line across the width of a lode chain.
Entry: Refers to mining location; also opening
to underground workings.
Erosion: The weathering disintegration and
movement of rocks and soils.
Evaporate: Drying out; also refers to the dry
product.
Exchange for Physical(EFP): A simultaneous
trade between traders wherein one trader buys the
physical and sells the futures contracts while the
other trader does the opposite. Prices for EFP transactions
are mutually agreed upon by both traders.
Exploration: Prospecting, sampling, mapping,
diamond drilling and other work involved in searching
for ore. Exploration can be divided into three basic
categories:
Grassroots Exploration: Exploration for ore
in an area that has the correct geologic setting,
although no ore may have been found yet in that precise
location.
Headframe Exploration: Exploration for a separate
ore body "within sight of the headframe"
of an existing mine.
Definition Exploration: Exploration that defines
an ore body or searches for extensions to it, once
it has been discovered.
Exposure: An outcrop of ore or a rock luvial;
Sand and gravel laid down by water movement.
Extralateral right: Right to minerals beyond
side lines of mining claims.
Extrusive: Igneous rocks that cooled at or
above the earth?s surface.
Exude: To ooze out, or emit an odor.
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F -
Face:
The surface of a working area that is to be mined.
Face Value: The nominal value given to legal
tender coin or currency (i.e., a 1-ounce gold American
Eagle has a face value of $50).
Fahrenheit: A system of temperature measurement.
False set: Temporary timbering in a mine.
Fault: A fracture or fissure in the earth?s
surface.
Feasibility Studies: Determinations of the
economic feasibility of mining a deposit, based on
progressively greater levels of information.
Fine gold: Pure gold of 1000 fine. Also very
small gold particles.
Fineness: In precious metals, the quantity
of pure gold, platinum, etc., contained in 1,000 parts
of an alloy. Gold bullion of .995 fineness contains
995 parts gold and 5 parts of another metal(s).
Fire assay: The assaying of metallic minerals
by use of a miniature smelting procedure with various
fluxing agents.
Fissile: Capable of being split or removed
in sheets, as slate and mica.
Fissure: An opening or crack in rock formations,
even if filled with rock.
Flask: Unit and container for measuring mercury,
equal to 76 pounds.
Float: Rocks that have broken off an ore deposit
and moved down-slope.
Floor: The bottom of a mining level in underground
mines.
Flotation: An ore milling process for concentrating
minerals based on the selective adhesion of certain
minerals to air bubbles in a mixture of water and
ground-up ore. When the right chemicals are added
to a frothy water bath of ore that has been ground
to the consistency of talcum powder, the minerals
will float to the surface. The metal-rich flotation
concentrate is then skimmed off the surface.
Flour: Extremely fine gold particles; also
finely-ground ore.
Flume: A trough used to convey water.
Fluvial: Sand and gravel laid down by water
movement.
Flux: Chemical or compound added to crushed
ore to aid in its reduction by heat, as in fire assaying.
Fold: A bending in a rock structure.
Foliated: Leaf-like formations of minerals.
Fools gold: Substances resembling gold in color,
like pyrite and mica.
Footwall: The rock underlying an ore deposit.
Formation: Denotes a particular rock structure;
also the processes by which a mineral deposit is formed.
Forward Contract: A cash rather than a futures
transaction in which the buyer and seller agree upon
delivery of a specified quality and quantity of metal
at a specified future date.
Fossil: Impressions of plants or animals in
rocks.
Four Nines: Gold with a fineness of .9999 -
the purest gold available.
Fracture: A break in a rock formation; surface
of a broken rock.
Fumarole: A site where fumes are expelled in
a volcanic area.
Furnace: Equipment for roasting or smelting
ores.
Fusion: The melting of a substance.
Futures Contract: A firm commitment to make
or accept delivery of a specified quantity and quality
of a commodity during a specific month in the future.
Futures Commission Merchant: An individual
or organization which solicits or accepts orders to
buy or sell futures contracts or commodity options,
and accepts money or other assets from customers in
connection with such orders.
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G -
Gangue:
Waste rock that surrounds an ore deposit; also the
valueless material in an ore.
Geode: A hollow nodule of agate, usually
lined with crystals.
Geology: Science dealing with the formation
of rocks, ores and minerals.
Geophysics: Analysis of rock formations by
use of physics.
Glacial: Of, or related to, glacial action;
produced by glaciers.
Gold mineralized material: Mineralization
based on geological evidence and assumed continuity.
May or may not be supported by samples but is supported
by geological, geochemical, geophysical or other
data. This material is sufficiently geologically
defined to be deemed to be potentially economic,
yet is not in a definitive mine plan. This material
requires a reasonable cut-off grade criteria and
has no untenable non-technical issues barring its
exploitation.
Gold table: Volume or weight of placer gravel
or an ore.
Gophering: Prospecting by means of hand dug
holes.
Gouge: Softer minerals lining the wall of
a vein or ore deposit.
Grade: The amount of valuable mineral in
each ton of ore, expressed as troy ounces per ton
or grams per tonne for precious metals and as a
percentage for other metals.
Grade: The metal content of ore. With precious
metals, grade is expressed as troy ounces per ton
of ore or grams per metric tonne of ore.
Graduated cylinder: Flask marked with lines
to indicate measured volumes.
Grain: Unit of weight. There are 480 grains
in a troy ounce.
Gram: Metric unit of weight. There are 31.103
grams in a troy ounce.
Granular: Composed of compacted mineral grains.
Graphitic: Containing carbon or graphite.
Gravity Separation: Recovery of gold from
crushed rock or gravel using gold's high specific
gravity to separate it from the lighter material.
Grizzly: Iron grating for screening out larger
rocks and boulders.
Gulch: A narrow or deep ravine or canyon.
Gully: A small ravine.
Gumbo: Very sticky or clayey mud.
Gutter: The lowest depression in the bottom
of a stream channel.
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H -
Hallmark:
Mark, or marks, which indicate the producer of a gold
bar and its number, fineness, etc.
Hanging wall: Rock overlying an ore deposit.
Hardpan: Cemented or compacted gravels and
clays.
Head-frame: Structure erected over the mouth
of a shaft.
Heads: Value of an ore before being milled;
also the ore itself.
Heap: Pile of ore stacked for leaching.
Heap leaching: Leaching of an ore pile with
cyanide solution to extract the precious metal content.
A process whereby gold is extracted by "heaping"
broken ore on sloping impermeable pads and repeatedly
spraying the heaps with a weak cyanide solution which
dissolves the gold content. The gold laden solution
is then collected for gold recovery.
High-grade: Rich gravels; to mine richer portions
of a deposit; also refers to stealing large pieces
of gold or rich ores.
Highgrading: Taking only richer ores.
Hilch: Hole in rock to support timbers; also
connecting objects together.
Homogeneous: Generally uniform throughout;
well mixed.
Horse: Chunk of worthless rock in an ore body.
Hydrated: Contains water in chemical combination.
Hydraulic: Related to water in motion, especially
under pressure. Also refers to force exerted by liquids
under pressure, including oils.
Hydrochloric acid: Acid composed of hydrogen
and chlorine.
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I -
Igneous:
Refers to rocks of molten or volcanic origin.
Impregnated: Rocks or minerals saturated
with some other substance.
Incline: A rising slope.
Incrustation: A coating or crust on a rock.
Indicated value: The preliminary value determined
for a placer sample, before it is adjusted or corrected
for known variables.
Initial Margin: Customers' funds required
at the time a futures position is established, or
an option is sold, to assure performance of the
customer's obligations.
In-the-Money Option: Call option - if the
futures price is above the strike price. Put option
- if the futures price is below the strike price.
Interedded: Occurring between distinct rock
layers or strata.
Intrinsic Value: The absolute value of the
in-the money amount - that is, the amount that would
be realized if an in-the-money option were exercised.
Intrusion: A mass of rock that has been forced
into or between other rocks.
Iridescence: Display of colors by diffraction
of light.
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J -
Jackhammer:
Term for rock-breaking pneumatic hammer or rock
drill.
Jet: Device for spraying water, also the
water spray itself.
Jig: Equipment for recovering heavy minerals
by gravity settling through vibrating baffle plates
surrounded by pellets of iron.
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K -
Keeve:
A large vat.
Kerb Trading: The trading which takes place
in all metals around 20 minutes after the official
market has ended. The kerb market enables a ring
member to complete business interrupted by the bell
in the official sessions. Originally, "kerb"
trading took place on the kerb outside the exchange,
hence the name.
Kilo Bar: A bar weighing one kilogram - approximately
32.1507 troy ounces.
Knob: An isolated, projecting hill or butte.
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L -
Lacustrine
deposit: Sediments deposited on the bottom of
lakes.
Lagging: Small timbers or planks used in underground
mines; also spikes used to nail timbers together.
Launder: A device for cleaning lighter waste
materials form ore.
Lay: The general direction or slope of a device
or ground surface.
Leach: Mineral extraction by dissolving minerals
in solution.
Leaching: The extraction of a soluble metallic
compound from ore by dissolving the metals in a solvent.
See also Heap Leaching.
Leach Cycle: The average amount of time that
ore is leached.
Leach Pad: A large, impermeable foundation
or pad used as a base for ore during Heap Leaching.
The pad prevents the leach solution from escaping
out of the circuit.
Dedicated Pad: A leach pad that is constructed
to permanently accommodate one ore heap. The pad forms
the tailings pile when economic recovery has been
reached and the pad neutralized.
Reusable Pad: A pad where ore is loaded and
then unloaded at the end of each Leach Cycle. The
pad, made of durable materials, can be reused continually.
Lead: The bottom portion of gold-bearing channel
gravels, particularly in buried placers.
Ledge: A horizontal layer of rock.
Legal Tender: The coin or currency which the
monetary authority of the issuing country declares
to be universally acceptable therein as a medium of
exchange; acceptable in the discharge of debts.
Lens: A mineral deposit shaped like an eyeglass
lens.
Lessee: The person leasing or optioning a mining
property.
Level: A horizontal tunnel or drift in an underground
mine.
Leverage: In futures, the advantage allowed
an investor by depositing funds that are less than
the value of the contract.
Linear: Along the length of an object or area.
Liquidity (or Liquid Market): The quality of
being readily convertible into cash. Refers to the
least cost at which one can enter and then close out
a position. A broadly traded market where buying and
selling can be accomplished with small price changes.
Lode: A relatively confined mineral deposit
lying within a rock formation.
"London Fix": Twice-daily bidding
session in London of the five major gold traders,
at which the price is fixed or set. The London Fix
is the basis for many gold contracts worldwide.
Long-hole open stope: A method of mining involving
the drilling of holes up to 90 feet long into an orebody
and then blasting a slice of rock which falls into
an open space. The broken rock is extracted and the
resulting open chamber is not filled with supporting
material.
Long and Short: A trader is long if he purchases
more metal or futures contracts than he sells. Conversely,
he is short if he sells more than he buys.
Long tom: A small, portable sluice for washing
placer gravel, usually built in several sections.
Luster: The character of light reflected by
minerals.
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M -
Macroscopic:
Visible to the unaided eye.
Magma: A mass of molten rock.
Magmatic Ore Deposity: Formed by differentiation
of mineral in magma.
Magnetic separator: A device that uses a strong
magnetic field to extract magnetic material from sands
or concentrates.
Malleable: Easily hammered and flattened when
cold; refers to metals.
Mallet: Wooden hammer for driving stakes.
Margin: Money deposited as a guarantee of performance
on the purchase or sale of a futures contract. On
hedge markets, these deposits are called original
or initial margins. If the market later fluctuates
against the holder of the contract, he is required
to make up the difference between his contract price
and the current market price by paying additional
funds called variation margins, also known as maintenance
margins. When prices fluctuate in the trader's favor,
excess variation margins may be withdrawn. (On NYMEX
and COMEX markets, not on the LME.)
Matrix rock: Gangue or rock that contains minerals
or ores.
Mesh: Related to the openings in a sieve or
screen.
Metallurgy: Science of ore processing and metals.
Metamorphism: Alteration of rocks subsequent
to their deposition.
Meteoric water: Surface water that sinks into
cracks and fissures.
Methane: An explosive mine gas composed of
hydrogen and carbon.
Metric tonne: Equal to 1.102 standard short
ton (U.S.).
Mill: Facility for processing ores or gravels.
A plant where ore is ground, usually to fine powder,
and the valuable metals are extracted by physical
and/or chemical processes.
Miner's inch: Water measure equal to 12.5 gallons
per minute.
Mineral: Solid substance having a regular and
definite chemical composition.
Mineralization: Mineral-bearing rock. Mineralization
generally refers to the presence of gold and silver
established by widely spaced Drilling.
Mining claim: A portion of the public lands
claimed for the valuable minerals occurring in those
lands; obtaining mineral rights under mining law.
Molecule: Smallest atomic combination that
comprises a certain compound.
Monitor: Device for measuring equipment or
processing operations.
Monolith: A single, large block of stone.
Monument: An object placed or erected to mark
boundaries of a mining claim.
Mother lode: A gold-bearing district in California
over 100 miles long. Also refers to very rich placer
in ore deposits.
Muck: A common term for waste rock in a mine;
also sticky mud.
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N -
Native
gold: Metallic gold in its free or uncombined
state. Placer gold.
Native metal: Metal that occurs naturally in
metallic form.
Nodule: A rounded lump or mass of mineral.
Non-metallic: Containing little or no metal;
industrial mineral.
Nugget: A lump or particle of native metal,
such as gold.
Numismatic: Coins which are valued for their
rarity, condition and beauty beyond the face value
of their gold content. Generally, premiums for numismatic
coins are higher than for bullion coins.
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O -
Occurrence:
Existence or how a mineral is deposited.
Open Interest: The total number of futures
contracts, whether purchased or sold, recorded on
the books of NYMEX which are not offset by the opposite
transaction or by physical delivery of the metal.
Open Outcry: The method of public auction
required for making bids and offers in the trading
pits or rings of commodity exchanges.
Open pit: A mine that is entirely on the
surface.
Option: A contract which gives the buyer
the right but not the obligation to buy or sell
a specified quantity of a metal or a metal futures
contract at a specified period of time, regardless
of the market of that metal or metal futures contract.
Option: An agreement to lease or purchase
a mining property.
Ore: Any rock that contains enough mineral
to be mined at a profit.
Orebody: A relatively confined ore deposit.
Ore Body: A mineral deposit that can be mined
at a profit under existing economic conditions.
Ore Reserves:
Ore: Rock generally containing metallic or
non-metallic minerals that can be mined and processed
at a profit.
Ore body: A sufficiently large amount of
ore that can be mined economically. Organic: Of
plant or animal origin.
Other Mineralization:
Outcrop: A projection of bedrock above the
ground surface.
Out-of-the-Money Option: An option with no
intrinsic value.
Overburden: Surface waste materials covering
a mineral deposit.
Oxide: Any chemical combination with oxygen.
Oxide ore: Mineralized rock in which some
of the original minerals have been oxidized. Oxidation
tends to make the ore more porous and permits a
more complete permeation of cyanide solutions so
that minute particles of gold in the interior of
the minerals will be readily dissolved.
Oxidize: To combine with oxygen.
Oxidized zone: Portion of ore deposit where
oxygen has displaced other non-metallic elements
in chemical combination with metals.
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P -
Parting:
Fire assay procedure for separating gold from other
metals.
Patent: A title deed to a mining property.
Pay streak: A layer or channel within a gravel
deposit that contains a much higher average gold content
that the surrounding gravels.
Phenocryst: A porphyritic crystal inclusion.
Pig: Common term for an ingot of cast metal.
Pillar: Column of ore left for roof support
in underground workings.
Pinched: Narrowed portion of a vein or ore
body.
Pipe: A pipe-like ore body or rock formation;
a diamond pipe.
Pitch: Refers to the relative angle of slope
or dip of an ore deposit.
Pitting: Digging test pits for sampling gravels.
Placer: Any concentration of the heavier and
more durable minerals that has resulted from the combined
actions of erosional forces.
Placer mining: Mining sand and gravel deposits
for their mineral content.
Porosity: The relative quantity of holes or
openings in a substance.
Position Limit: The maximum position, either
net long or net short, in one metal future or in all
futures of one metal combined which may be held or
controlled by one person as prescribed by an exchange
or the Commodity Futures Trading Commission.
Precipitate: The material that settles from
a liquid solution when a particular substance is added
to the solute.
Premium: In gold bullion, the amount by which
the market value of a gold coin or bar exceeds the
actual value of its gold content. Part of the premium
is recovered by the seller at resale. In options,
the price of the option.
Primary: The original or unaltered form.
Prospecting: The search for valuable mineral
deposits.
Proven ore: Material for which tonnage and
grade are computed from dimensions revealed in outcrops,
trenches, underground workings or drill holes; grade
is computed from the results of adequate sampling;
and the sites for inspection, sampling and measurement
are so spaced and the geological character so well
defined that size, shape and mineral content are established.
Probable ore: Material for which tonnage and
grade are computed partly from specific measurements,
samples or production data and partly from projection
for a reasonable distance on geological evidence;
and for which the sites available for inspection,
measurement and sampling are too widely or otherwise
inappropriately spaced to outline the material completely
or to establish its grade throughout.
Put Option: An option that gives the option
buyer the right but not the obligation to sell the
underlying futures contract at a particular price
on or before a particular date.
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Q -
Qualitative
analysis: Determining which metals are present
in a sample.
Quantitative analysis: Determining how much
of a metal is present.
Quartz: Silicon dioxide; a common gangue mineral.
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R -
Ramp:
An underground tunnel providing access for exploration
or the movement of materials and equipment between
mine levels.
Ramp: An inclined underground tunnel which
provides access for exploration or a connection between
levels of a mine.
Reaming: Enlarging the diameter of a hole.
Recovery: The rate and amount of valuable minerals
processed and extracted from a placer deposit.
Recovery Rate: The percentage of metals recovered
in a mineral separation process. Recovery rates vary
considerably depending on physical, metallurgical
and economic circumstances.
Reclamation: The process by which lands disturbed
as a result of mining activity are reclaimed back
to a beneficial land use. Reclamation activity includes
the removal ofbuildings, equipment, machinery and
other physical remnants of mining, closure of tailings
impoundments, leach pads and other mine features,
and contouring, covering and revegetation of waste
rock piles and other disturbed areas.
Recovery rate: A term used in process metallurgy
to indicate the proportion of valuable material obtained
in the processing of an ore. It is generally stated
as a percentage of the material recovered compared
to the total material present.
Refining: Extracting and purifying metals and
minerals. A process of removing impurities from metals
by introducing air and fluxes into the molten metal.
The impurities are removed as gases or slag.
Refractory material: Gold mineralized material
in which the gold is not amenable to recovery by conventional
cyanide methods without any pre-treatment. The refractory
nature can be either silica or sulphide encapsulation
of the gold or the presence of naturally occurring
carbons which reduce gold recovery.
Reserves: That part of a mineral deposit which
could be economically and legally extracted or produced
at the time of the reserve determination. Reserves
are customarily stated in terms of ore when dealing
with metalliferous minerals. There are two categories
of reserves.
Residual: Left over; eroded in place.
Restrike: A modern replica of previously issued
coins. Governments and their mints can choose to "restrike"
a previous issue rather than introduce new coinage.
Rime: A groove or ridge in the bottom of a
stream channel; a slat or block of wood or metal placed
across a sluice box or other placer unit.
Roast: To heat an ore to drive off volatile
substances or oxidize the ore.
Roasting: The treatment of ore by heat and
air, or oxygen enriched air, in order to remove sulphur,
carbon, antimony and arsenic.
Room & pillar: A mining method for underground
mines where most of the rock is removed and pillars
are left intact to provide roof support.
Run-of-Mine Ore: Uncrushed ore in its natural
state just as it is when blasted.
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S -
Saddle:
Formation shaped like a saddle or anticline.
Salting: Intentional or unintentional enrichment
of a sample.
Sampling: The process of selecting and taking
samples from a mineral deposit.
Second-foot: A unit of water measure equal
to one cubic foot per second, or 448.83 gallons per
minute.
Secondary: An alteration of an original formation
or deposit.
Sediment: Eroded material transported and deposited
by water movement.
Sedimentary: Formed by the deposition of eroded
material. Pertaining to sediments laid down by rivers
and streams.
Segregated Account: A special account used
to hold and separate customers' assets from those
of the broker or company.
Semi-autogenous grinding (SAG): A method of
grinding rock into fine powder whereby the grinding
media consist of larger chunks of rock and steel balls.
Settlement: The daily price at which the clearinghouse
settles all accounts between clearing members for
each contract month. Settlement prices are used to
determine both margin calls and invoice prices for
deliveries. The term also refers to a price established
by the clearing organization to calculate account
values and determine margins for those positions still
held and not yet liquidated.
Shaft: A vertical accessway to a mine. Shafts
are used for the movement of personnel and materials,
including ore and non-mineralized rock.
Shaft: A vertical passageway to an underground
mine for moving personnel, equipment, supplies and
material including ore and waste rock.
Shear zone: Area in which rock has been crushed,
shattered or displaced. Formed by combined action
of rivers and oceans.
Shieve: Common term for a pulley.
Sill: An intrusive sheet of igneous rock.
Single jack: A light hammer used for drilling
holes by hand.
Skim-bar: A superficial, thin layer of gold-bearing
sand and gravel that accumulated on the surface of
river gravel deposits.
Slip: Refers to displacement along a fault.
Slope: An inclined entry to underground workings.
Smelting: Reducing metallic ores in a furnace.
Smelting: A metallurgical operation in which
metal is separated from impurities by a process that
includes fusion.
Specific gravity: The relative weight of a
mineral as compared to the weight of an equal volume
of water.
Specimen: A selected piece of rock or ore taken
for examination or display.
Speculator: A person who trades in metals,
either futures or physicals, for a purpose other than
hedging.
Spiral concentrator: A revolving drum or pan
with an interior section made of spiral riffles, used
for gravity concentration of heavy minerals.
Spot Price: The current price in the physical
market for immediate delivery of gold. Sometimes referred
to as the cash price.
Spread: The price at which a commodity or security
will change hands if an option is exercised.
Stamps: Piston-driven rock crushing rods.
Stockwork: A lattice-like network or ore veinlets
in fractured rock.
Stope: An area in an underground mine where
ore is mined. A drift working above the main mine
level.
Stratified: A formation having banded layers.
or beds.
Striated: Having very fine parallel grooves
or scratches.
Stringer: A narrow ore vein or veinlet.
Stripping: Removal of overburden or waste rock
.
Stripping Ratio: In an open pit mine, large
quantities of nonmineralized rock often cover up the
ore and must be removed. The Stripping Ratio is the
number of tons of non-mineralized material removed
per ton of ore mined.
Structure: The general form and type of rock
formation.
Sulphide ore: A sub-group of refractory ore
- mineralized rock in which much of the gold is encapsulated
in sulphides and is not readily amenable to dissolution
by cyanide solutions associated with sulphide minerals
(primarily pyrite) that have not been oxidized. Some
sulphide ore may require autoclaving or roasting prior
to milling.
Sump: A hole sunk below a mine operating area
to collect water seepage. Surf washer: A small sluice
that is placed so that the incoming surf can run up
and down the trough, washing material from a hopper
down over riffles.
Syncline: A folded rock formation that dips
downward.
Tabular: A plate-like structure in certain
minerals.
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T -
Tabular:
A plate-like structure in certain minerals.
Tail: The string of gold particles left in
a pan after the material has been concentrated by
washing.
Tailings: The waste materials left over and
ejected from the outlet of processing equipment after
the valuable minerals have been removed. The neutralized
material discarded after the economically recoverable
metals have been extracted from the ore by a Mill
or by Heap Leaching.
Talus: Broken rock at the bottom of a slope.
Tamping: Compacting material over an explosive
range. Tenor: The relative value or mineral content
of an ore.
Terrace:
A relatively flat area lying between the various
levels of bench gravels.
Till: An unstratified and unconsolidated
sediment deposited by glaciers.
Time Value: Any amount by which an option
premium exceeds the option's intrinsic value.
Topography: The physical features of the
surface in an area.
Ton: A unit of weight equal to 2,000 pounds
or 307.2 kilograms.
Trend: Direction or bearing of any rock formation.
Trommel: A heavy-duty revolving drum and
screen, utilized for washing, breaking up, and removing
larger rocks and retrieving the sands and pebbles
for processing in other placer recovery equipment.
Troy ounce: The most common unit of weight
used to measure quantities of precious metals. One
troy ounce equals 1.09714 avoirdupois ounces or
31.103 grams. Of a fineness of 999.9 parts per 1,000
parts.
Troy weight: System of weights for the precious
metals.
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U -
Ultra
basic: Igneous rocks containing less than 35%
silica.
Umpire assay: Verification of assay results
by another assayer.
Unpatented claim: Usual lode, placer or millsite
claim located under the mining laws.
Upcast: A vertical raise to the ground surface
form an underground mine.
Upper lead: Pay gravel of pay streak in a gravel
deposit that lies in strata well above bedrock.
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V -
Values:
The valuable minerals contained in a deposit, usually
refers to the precious metal content.
Vein: A well-defined mineralized zone within
a confined space.
Volume: A measurement of the amount of material
in a placer, usually stated in cubic outwards.
Volume factor: A factor which takes into account
the swell of loosened gravels after the material has
been excavated. Most intact gravels swell at least
25 percent when they have been loosened.
Vug: An open cavity in a rock.
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W -
Wall:
The sides of a mine working; rock on either side of
an ore body.
Warrant or Warehouse Receipt: Certificate or
physical deposit, which gives title to physical metal
in an exchange-approved warehouse and which is recognized
as good delivery against a short position. Title to
the metal passes when the warrant is endorsed by its
current owner to a new owner.
Water management: Process whereby the groundwater
table m the mining area is lowered by pumping water
from wells, and the water is conveyed and used or
recharged to the groundwater system through infiltration,
reinjection or irrigation return.
Water table: The underground level at which
the ground is saturated with water. The level at which
water will stand in an excavation.
Winze: A shaft sunk in the interior of an underground
mine for ventilation or development purposes.
Workings: Any mine excavation or operating
areas.
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Y -
Yardage:
The number of cubic yards of gravel contained in a
placer deposit; also the number of cubic yards mined
and processed per hour or per day.
Yield: The value of minerals produced from
a deposit per unit of time.
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Z -
Zircon:
A durable, crystalline form of zirconium silicate
that is commonly found in placer deposits.
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