GLOSSARY OF TERMS
ACID MINE WATER: Mine water that contains free sulfuric acid, mainly due to the
weathering of iron pyrites.
ACTINOLITE: A colorless to green mineral that darkens with increased iron content
from green to black.
ACTIVE WORKINGS: Any places in a mine where miners are normally required to
work or travel and which are ventilated and inspected regularly.
ADIT: A horizontal or slightly inclined entrance into a mine from the surface, by which a
mine is entered and dewatered.
AGGLOMERATION: A family of processes that can be used to concentrate valuable
minerals based on their adhesive properties.
AIRWAY: Any passage through which air is carried.
ALCHEMY: The forerunner of modern chemistry. Its chief aims were the transmuting of
baser metals into gold and the discovery of an elixir of life.
ALLOY: A result of two or more metals being melted or otherwise joined together.
Alloys may be formed to harden or strengthen certain metals, such as when silver is
added to gold, or to produce a metal not found in nature, such as when copper and zinc
are joined to form brass. Alloys have properties different from those of their constituent
elements: for example, they are poorer conductors of heat and electricity, they are often
harder, and, with the exception of aluminum alloys, they are more resistant to corrosion.
ALLUVIAL MINING: The practice of working a natural alluvial fan. Alluvial fans are
found where, over many centuries, water has eroded great mountains and deposited wide,
sloping “fans” of loosely packed dirt, stones, gravel, and boulders where the land levels.
AMALGAMATION: A mining term relating to the combination of a metal—such as
silver, platinum, or gold—with mercury. Amalgamation is one of the simplest and easiest
ways of recovering fine gold from concentrates.
ANCIENT STREAMBED: The result of a river being forced to change its course and
seek an alternate route, due to a landslide, earth tremor, or other natural force. “Old
channels” are eagerly sought by prospectors, as their gold-bearing gravels have never
been touched.
ANTICLINE: An upward fold or arch of rock strata.
APRON: The part of the rocker that is stretched across a frame, at an incline, beneath the
hopper. The apron is made of burlap or canvas and traps the fine particles of gold as they
fall through the perforated holes of the hopper’s bottom.
AQUA REGIA: A mixture, containing one part nitric acid to four parts of hydrochloric
acid, that is strong enough to dissolve gold and platinum.
AQUIFER: A water-bearing bed of porous rock, often sandstone.
ARCHING: A fracture process that stabilizes the rock around a mine opening by creating
an arching effect.
ARGENTITE: An ore in which silver is found.
ARSENOPYRITE: An iron arsenic sulfide. It is a hard, metallic, opaque, steel grey to
silver white mineral.
ASSAY: The evaluation or analysis of ore to determine the proportion of gold, silver, or
other valuable metals. Usually an assay is done by chemical methods and is fairly
accurate.
ASSIMILATION: The process by which mercury can absorb gold, silver, or platinum
into a common ball, or alloy, called amalgam, while ignoring lighter sands and gravel.
AVOIRDUPOIS WEIGHT: The common English and American system of weight
measure. This system is not used for medicine, gold, or other precious minerals.
437.5 grains = 1 ounce
7000 grains = 16 ounces
16 ounces = 1 pound
BAKED POTATO METHOD: A method of separating gold from the amalgam.
BAR: A term given to a submerged sandbar in a creek or river. Bars increase in size as
dirt, sand, gravel, black sands, and gold are deposited. Sandbars have produced great
quantities of gold in the past and should not be overlooked today.
BASE-METAL MINING: The mining of metals such as copper, lead, zinc, tin, aluminum, and so forth,
as opposed to precious metals such as silver, gold, or platinum.
BATTERY: Another name for a stamp mill.
BEAM: A bar or straight girder used to support a span of roof between two support props
or walls.
BEDROCK: A term that originally was used to refer to the solid rock bottom of a stream
or river. A false bedrock is formed when the feldspar portion of eroded rocks gathers and
settles, creating a tough clay or cemented gravel. The largest quantities of gold are
generally recovered within a couple of feet above bedrock.
BENCH: A flat area above a stream or river.
BLACK DAMP: A term generally applied to carbon dioxide. Strictly speaking, black
damp is a mixture of carbon dioxide and nitrogen. It is also applied to an atmosphere that
is depleted of oxygen, rather than having an excess of carbon dioxide.
BLACK SAND: A type of sand, usually composed of hematite and magnetite, that is heavier than ordinary
sands and that settles in much the same manner as does gold. Because of their properties, black sands are good
indicators of gold and should never be overlooked.
BLASTING CAP: A detonator containing a charge of detonating compound, which is
ignited by electric current or the spark of a fuse. Blasting caps are used for detonating
explosives.
BLEEDER OR BLEEDER ENTRIES: Special air courses developed and maintained as
part of the mine ventilation system and designed to continuously move air-methane
mixtures emitted by the gob or at the active face away from the active workings and into
the mine’s return air courses.
BONANZA: A term used to describe an exceptionally rich and persistent vein of ore,
usually gold.
BOREHOLE: Any deep or long drill hole, usually associated with a diamond drill.
BROW: A low place in the roof of a mine, giving insufficient headroom.
BULLION: A term used to describe raw gold or silver that is ready to be shipped to the
mint. When the metal has been reduced to nearly pure form, it is then cast into bars or
ingots for easy storage and shipping.
BYPRODUCT: A secondary product obtained while mining something else. For
example, gold is often a byproduct of a copper mining operation, meaning that copper is
the main metal mined, but some gold is also recovered.
CACHE: A temporary hiding place for gold or other wealth, including supplies, food, or
equipment. The word cache is basically used to refer to anything hidden by the owner
until his or her return.
CAGE: In a mine shaft, the device, similar to an elevator car, that is used for hoisting
personnel and materials.
CALAVERITE: A gold ore with a whitish, metallic luster, composed of gold in
combination with tellurium.
CAR: A railway wagon, especially any of the wagons adapted to carrying ore, and waste,
underground.
CARAT: A measure of weight for gold or precious gems. Pure gold is 24 carats.
CELESTIALS: An expression used to describe Chinese miners. The term was in
widespread use during the California gold rush, and was brought into British Columbia
when the forty-niners came north.
CEMENTED GRAVEL: A hard, tightly packed material that is frequently rich in gold. It
can accumulate and form a false bedrock.
CHALCOPYRITE: A copper iron sulfide mineral that crystallizes and has a brassy to
golden yellow color.
CHINA DIGGINGS: A term used to describe an area that was abandoned by most
people as unprofitable, but was still being worked by the Chinese. Some of these often
proved to be far richer than thought.
CLAIM: An area that has been filed with the proper government agency for the
extraction of gold or other metals. The prospector then has the rights to the minerals
within the claim for a certain period of time. The boundaries of the claim were marked by
stakes, piles of rocks, and so forth. A can containing the description and particulars of the
claim was usually placed on or near one of the posts.
CLAIM JUMPER: Someone who seizes or illegally restakes a claim that has already
been filed by another prospector.
COARSE GOLD: Rough, unrefined nuggets of gold, which vary in size. Gold that has
traveled a considerable distance is usually worn smooth; therefore, coarse gold is an
indication of limited travel.
COLOR: A term used to describe the minute specs of gold in gravel. Colors, though
themselves minuscule, are indicators of gold in a particular stream or river.
COMMINUTION: The breaking, crushing, or grinding of ore or rock.
COMPETENT ROCK: Rock that, because of its physical and geological characteristics,
is capable of sustaining openings without any structural support except pillars and walls
left during mining.
CONCENTRATES: The name given to the material that remains in the gold pan, rocker,
sluice, and so forth, after washing. Concentrates are usually composed of black sands,
gold, and silver, but particles of platinum and a variety of other minerals could be
included.
CORE DRILL: A drill used specifically to remove a cylinder of material from solid rock,
so that material can be tested for mineral content without blasting away tons of rock. The
material extracted by the drill is referred to as the core sample.
CORE SAMPLE: A cylindrical sample, generally 1"–5" in diameter, drilled out of an
area to determine the geologic and chemical analysis of the overburden and of coal.
CRETACEOUS: One of the major divisions of the geologic timescale, reaching from the
end of the Jurassic period, millions of years ago, to the beginning of the Paleocene epoch.
CREVICE: A crack or narrow fissure in bedrock, which tends to accumulate and trap
gold. Small cracks can hold large quantities of gold, and are usually the best prospects for
the gold panner.
CRIB: A roof support of prop timbers or ties, laid in alternate cross-layers, log-cabin
style. It may or may not be filled with debris. It also may be called a chock or cog.
CROSSCUT: A passageway driven between the entry and its parallel air course or air
courses for ventilation purposes. Also, a tunnel driven from one seam to another through
or across the intervening measures; sometimes called a “crosscut tunnel” or a
“breakthrough.”
CRUSHER: A machine for crushing rock or other materials. Among the various types of
crushers are the ball mill, the gyratory crusher, the Handsel mill, the hammer mill, the
jaw crusher, the rod mill, rolls, the stamp mill, and the tube mill.
DEAD WORK: A phrase used by prospectors to describe the work of clearing away
overburden to get at the gold-bearing gravel.
DEPOSITS: A term that usually refers to an area where gold or other metal has been
found. There are two types of placer deposits: eluvial deposits, located near the
originating lode; and alluvial deposits, found at considerable distances from the
originating lode.
DIGGINGS: A name usually applied to claims that were currently being worked for
gold, silver, or other ore.
DIORITE: A grey to dark grey intermediate rock that can contain small amounts of
quartz.
DISCOVERY CLAIM: The first claim filed on a given stream or river. The other claims
were then staked above and below the discovery claim, which was legally larger than any
other claim on the creek.
DREDGE: A machine used for scooping or sucking gold-bearing gravel from the
riverbed. There are numerous types and sizes of dredges, ranging from the small,
portable, compact models that can easily be operated by one person to large, barge-type
dredges used for clearing mud from harbor entrances.
DRIFT: A horizontal shaft that leads from a central deposit of ore. Drifts can run for
hundreds, or even thousands, of feet as miners tunnel to trace tiny seams of gold fanning
out from the original strike.
DRY PLACER: A deposit of gold or precious metal found on dry ground.
DRY WASHER: A device used to work claims without the use of water. A dry washer
uses a small billow to blow away the light materials, leaving the gold and heavy particles
to be panned later.
DUST: A term used to refer to particles of gold so minute that they resemble dust. In the
old days, the amount of gold dust a miner could pinch between his thumb and forefinger
constituted one dollar.
EL DORADO: A term, originally derived from a Spanish legend about a land of gold and
plenty, that is now used frequently to describe a place of fabulous wealth or a region
abounding in gold and precious gems.
FINE GOLD: Generally, a term that refers to gold that can pass through a 40-mesh
screen. It includes fine gold and dust, which, in your pan, will appear as color so small
that it can only be collected by amalgamation.
FINENESS: A word used to indicate the purity of gold.
FLAKE GOLD: Small chips of gold, or pieces that have been flattened in transit.
FLOTATION PROCESS: A method for recovering gold from crushed ore and
concentrates.
FLOUR GOLD: An extremely fine gold that is difficult to save. It is uneconomical to
pan flour gold because of its very small flakes and pinpoints of gold.
FLUME: An inclined waterway, most often a channel dug in a hillside to transport water
to hydraulic mining camps. Simply described, flumes are similar to long series of sluices.
FRACTION: A small portion of ground lying between two claims, which the claimants
on either side could not stake without exceeding their legal limits. “Twelve-foot” John
was so named after a twelve-foot fraction on Gold Creek that he worked, which was
located between two other claims. After recovering over $12,000, John sold the fraction,
which then went on to yield over $100,000.
GEOLOGY: The science of the rocks and strata of the earth’s crust.
GLORY HOLE: A term used by miners to describe a small but unusually rich deposit of
gold.
GOLD RUSH: The wild scramble by prospectors to reach the new goldfields.
GRAIN: A term used to describe small particles of gold; grain is also used as a unit of
weight.
GRANODIORITE: A medium- to coarse-grained rock that is among the most abundant
intrusive igneous rocks. It contains quartz and is distinguished from granite.
GRAVEL: The gold-bearing material in a stream that you must wash to recover gold.
GRIZZLY: A device used to keep rocks and boulders out of a sluice box.
HARD-ROCK MINING: A term that usually refers to quartz mining. The process is said
to have originated in California about 1850. First a main shaft had to be sunk, then
horizontal shafts or drifts would be cut that followed the various seams of what was being
mined as they led from the main deposit. As this type of mining required a sizable
investment, the small operator was quickly eliminated.
HAULAGEWAY: Any underground entry or passageway that is designed for transport of
mined material, personnel, or equipment; a haulageway is usually equipped with a track
or belt conveyor.
HEAD FRAME: The heavy timber frame found above most hard-rock mine sites. It was
used to hoist ore from the depths of the mine, and also as an elevator to hoist and lower
workmen.
HOPPER: The tray in the upper end of a rocker.
HYDRAULIC MINING: A mining process in which water under great pressure was
discharged through giant nozzles, called monitors, against a gold-bearing hillside. The
force of the water would wash away the hillside, flushing the silt and gravel through
sluices where it could be separated and the gold recovered. Hydraulicking could—and
often did—completely ruin the landscape.
INGOT: A metal bar, especially of silver or gold, usually cast from a mold for
convenience in handling and measuring.
LITHOLOGY/PETROLOGY: A field of geology that focuses on the study of rocks and
the conditions in which they form.
LODE: A metallic vein in the earth’s crust, especially one of silver or gold. Lodes are the
original source of placer gold.
LONG TOM: A special sluice box of extra length, designed to capture extra-fine
particles of gold.
LOW-GRADE DEPOSITS: Deposits of gold, silver, or other metals that exist in
insufficient concentrations to be worked economically, except through large-scale
methods.
MERCURY: A heavy, liquid metal, silvery white in color, with a very low melting point.
Mercury is used to recover gold, silver, and platinum from concentrates; it is also called
quicksilver.
MINERAL: An inorganic compound, occurring naturally in the earth’s crust, that has a
distinctive set of physical properties and a definite chemical composition.
MOLYBDENUM: A lead-like element. Molybdenum has the sixth-highest melting point
of any element, and for that reason it is often used in high-strength steel alloys.
MOTHER LODE: A vein or streak of gold or other precious metal in the earth’s crust
from which placer deposits originate.
NOBLE METALS: Metals that do not have great chemical activity, such as gold, which
is neither corroded by moisture nor affected by oxygen or ordinary acids.
NUGGET: A rough lump or mass of native gold of no particular size. Nuggets range in
size from the head of a match to nearly two hundred pounds.
ORE: Rock containing metals or their compounds in sufficient quantities to be mined.
OUNCE A DAY: A measure of production. In the early days, ground that yielded an
ounce of gold a day, through panning, was considered rich ground.
OUTCROP: The point where a vein of quartz comes to the surface of the earth’s crust
and is visible.
OVERBURDEN: Generally, the low-grade material that must be first cleared away to get
at the rich, gold-bearing gravel just above bedrock.
PANNING: The act of washing gold-bearing gravel using a gold pan.
PAYDIRT: A term used to describe an area where a prospector has found gold, as in, “he
struck paydirt.”
PENNYWEIGHT: A troy weight equal to 24 grains.
PETERED OUT: A common expression that applied to a claim, mine, or deposit that
had been thoroughly worked over so that only worthless rubble was left behind.
PILLAR MINING: A method of underground mining in which approximately half of the
ore is left in place to support the roof of the active mining area. Large “pillars” are left
while “rooms” of ore are extracted.
PLACER: Generally, a word used to refer to deposits of gold-bearing gravel.
PLACER MINING: The act of recovering gold from placer deposits by means of a gold
pan, rocker, sluice, dredge, and so forth. Placer mining depends largely on water for
washing and separating the gold and gravel.
POCKET: An unusually large concentration of gold in a small area.
POKE: A small leather bag or pouch, usually two inches wide and six inches deep, with a
drawstring at the top. Pokes were used by miners as wallets to carry gold dust and
nuggets.
POORMAN’S DIGGINGS: A term used to describe an area that could be worked by a
miner with a rocker or sluice and with very little capital. The term was not used to
indicate that the area being worked was low grade or yielding small quantities of gold.
PORPHYRY: A type of granite rock characterized by large conspicuous crystals set in a
matrix of finer crystals; porphyry is often used as decorative stone and in building
construction.
PORTAL: The structure surrounding the immediate entrance to a mine; also, the mouth
of an adit or tunnel.
POT HOLE: A cavity formed in bedrock by the action of stones in the eddy of a stream.
Pot holes are highly overrated as gold producers, as any gold caught in them is eventually
ground into fine dust and escapes.
PROSPECTING: The act of searching for gold, silver, copper, lead, or any other
valuable metal. In the case of placer gold deposits, the prospector retrieves the gold as he
finds it, thus becoming a miner. If lodes or low-grade metals are located, the prospector
usually sells or leases the rights to them to a large mining company that has the necessary
equipment and resources to mine them, and he continues looking, or “prospecting,” for
new finds.
PROUSTITE: A sulfosalt mineral consisting of silver sulfarsenide. Proustite is also
known as light red silver or ruby silver ore and is an important source of the metal.
PYRARGYRITE: A mineral consisting of silver sulfantimonide. Pyrargyrite is also
known also as dark red silver ore or ruby silver and is an important source of the metal.
PYRITE: A name for many compounds of metals that contain sulfur or arsenic,
especially iron pyrites or copper pyrites. Pyrite is brass yellow and brittle, but because of
its color it is often mistaken for gold and hence is also known as “fool’s gold.”
PYRRHOTITE: An unusual iron sulfide mineral with a variable iron content; it is similar
to pyrite in color, and it is weakly magnetic.
QUARTZ: One of the most common materials associated with mother lodes. Quartz
consists of pure silica or silicon dioxide and is formed of masses of hexagonal crystals.
Quartz may be transparent, translucent, opaque, colorless, or colored. Most of the hardrock mining done for gold involves mining quartz veins.
RAISE: A secondary or tertiary inclined opening, which may be vertical or near-vertical,
that is driven upward from one level to connect with the level above, or to explore the
ground for a limited distance above one level.
RECOVERY: The act of “recovering” fine gold from the heavy concentrates, usually
through amalgamation.
RIDDLE: A large perforated iron sheet that forms the bottom of the hopper in a rocker
and is used for sifting or screening gravel.
RIFFLES: Obstructions that line the bottom of a rocker, sluice or dredge and collect the
fine gold. Different types of riffles include common riffles, zig-zag riffles, block riffles,
stone riffles, pole riffles, and so forth.
ROCKER: A device consisting of a box that rests on “rockers” and that is used to wash
placer deposits.
SAMPLING: The act of taking a cutting from a representative part of an ore deposit. The
sample should truly represent the deposit’s average value.
SHAFT: A primary vertical or non-vertical opening through mine strata, used for
ventilation or drainage and/or for hoisting of personnel or materials. A shaft connects the
surface with underground workings.
SLUICE BOX: A device invented by a party of Nevada miners in 1850. A sluice box
consists of a long trough leading down from a claim to a Long Tom. The sluice was an
immediate success; it became a standard tool of the California gold rush, and was later
brought north into Washington and Canada.
SLUICING: The act of washing gold from river gravel through the use of a sluice box.
SNIPING: Miner’s jargon for the act of prospecting and reworking old claims, dumps,
and other sites that have been abandoned.
SPHALERITE: A mineral that is the chief ore of zinc and almost always contains
variable iron.
STAKE: A term used to refer to the act of “staking” a legal claim by following the
necessary regulations, or to refer to the occasions when a miner has accumulated enough
gold to retire, either temporarily or permanently. In the latter case, the miner is said to
have “made a stake.”
STAMP MILL: A piece of heavy machinery that is power-operated and that is used to
smash hard-rock ore into a powder so that it can be processed for gold or other precious
metals.
STOPE: An area in the mine supported by surrounding pillars of standing rock in hardrock mining. An excavation in the form of steps made by mining ore from steeply
inclined or vertical veins.
STRIKE: A term used to denote the discovery of gold or silver. Once a “strike,” or
discovery, had been made, hundreds, or even thousands, of prospectors would swarm into
the area.
STULL: A timber placed between two walls of a stope as part of a protective covering or
platform.
SULFANTIMONIDE: A complex salt in which a metal is combined with sulfur and
antimony.
SYNCLINE: A downward-curving fold of rock with layers that dip toward the center of
the formation.
TAILING: Mining waste material that is left or discarded after precious metal has been
removed from ore. Also called dumps, tailings are generally piles of rocks or debris left
from the mining operation. Once considered worthless, tailings have become a target for
modern prospectors. Occasionally, large nuggets were discarded with the stones, or else
valuable metals, unknown to early prospectors, were tossed aside.
TRESTLE: A wooden frame consisting of braced legs fixed underneath horizontal bars,
used to support a sluice or a series of sluices.
TROY WEIGHT: A system of weight measurement for precious gems and metals.
24 grains = 1 pennyweight
20 pennyweights = 1 troy ounce
12 troy ounces = 1 troy pound
TUNNEL: A horizontal, or near-horizontal, underground passage, entry, or haulageway
that is open to the surface at both ends. A tunnel (as opposed to an adit) must pass
completely through a hill or mountain.
WET PLACER: A deposit of gold or other precious metal located under water.
WING DAM: A dam that divided a riverbed that miners wanted to work, lengthwise,
allowing water to flow through sluice boxes and other devices set up to wash the gravel.
WINZE: A secondary or tertiary vertical or near-vertical opening sunk from a point
inside a mine for the purpose of connecting with a lower level or of exploring the ground
for a limited depth below a level.