GLOSSARY OF MINING AND PROSPECTING TERMS
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Some really rusty gold! ...Find out why in our DredgeMaster course.
Adjustable Sluice: The bottom angle of the sluice box can be raised or
lowered as required depending on the condition oof the material being run, water volume,
Amalgamation: The process of using mercury to recover micron gold and
other gold pieces too small to recover easily by panning, gold wheel, bowl or other methods of separating
Ancient Streambed Material: Gravel that is in place from a previous
river course or the one that is there now but has changed course or eroded a deeper channel, stranding
potentially valuable gold deposits in various locations above and below the water line.
Assay: That process by which ore (or metal) is tested to determine what
kind of metals are present and how pure the metal is that is in the sample.
AuWhatfun: Site owner's pen name.
Bang Box: See Header Box
Bar: Gravel or Iron? A gravel bar is formed in the low pressure
areas of rivers and creeks, most often on inside bends. Iron- See "Prybar".
Bedrock: The rock crust of the earth. Placer gold can't penetrate this
layer except in cracks and fissures, though sometimes it can be found several feet into decomposed
Bench: A level or nearly flat area on a hillside.
Bench Deposit: A gravel deposit that is above the modern water line,
usually made up of Ancient Streambed material.
Black Sand: Sand that contains large amounts of iron, hematite,
magnetite and other dark, heavy minerals.
Boulder: Larger than a cobble, can not be picked up by one
Boulder Bound: That
condition in a working dredge hole where you uncovered so many boulders that were too large to remove from the
work area that progress becomes difficult or impossible to continue.
Cemented Gravel: Gravel that is so tightly packed together that it is
reminiscent of concrete. Very difficult to dredge.
Claim: An area usually in 20 acre increments of size, in which
the minerals are "claimed" by a person or association of persons for the purpose of extraction for profit. Rules
for filing and maintaining a "Claim" vary depending on local, State and Federal laws.
Classification: The process of separating sand and gravel into various
sizes using screens with uniform size holes for the purpose of making the process of extracting the "values"
from the gravel more efficient.
Classified Gravels: The state of the concentrated gravels after the
process of classification.
Cleaned Out: An area that has already been mined.
Clean-Up: The process of removing the concentrates from a sluice box
after processing sorted or unsorted materials through the box.
Clouded Out: When dredging and the silt gets stirred up, lowering or
obliterating your visibility.
Cobble: Rocks that are too big to pass through the dredge nozzle, but
not so big that one man can't easily move them.
Color: Traces of gold that can be seen with the naked
Concentrates: The heavy (usually) black sand and metal
particles that are left in a sluicebox after processing bank run or pre-sorted gravels from a
mining operation usually involving a bare sluice box, a sluicebox on a dredge or a
Crevice: A wide crack in the bedrock.
Dive Mask: A device used to see underwater, usually styled like oversize safety
goggles, but some versions integrate the regulator and face mask in one unit. The better Dive Masks allow you
to exhale through a purge valve in the mask making it easier to keep your mask clear for better
Dredge: A machine that usually floats on top of the water that is
designed to draw the sand and gravel up from the bottom of the body of water (lake, stream, river, ocean, etc.)
and deliver that material through a sluicebox in which riffles and materials are placed to allow the
heavier particles such as gold and other precious metals and gems to be trapped as "concentrates" and the
lighter gravels pass on through and are deposited back into the body of water a few feet from where they were
originally picked up. The dredge basically functions like an underwater vacuum, only retaining selective
Dry Suit: A dive suit designed to keep you dry while underwater. These
are designed to keep you warmer in very cold water temperatures.
Dust (gold dust): Bits of gold too small to grasp with your
Face Mask: See "Dive Mask".
Fines: Same as dust or gold dust.
Flour Gold: No, you don’t bake gold bread with this flour! It’s another name for gold
Free Gold: Any gold that does not need chemicals to be separated from concentrates or
Glory Hole: We all hope to hit one of these some day! It is an ultra rich spot that
yields so much gold that when telling about it afterwards, there is no need to exaggerate the
Gold Nugget: see "Nugget"
Gold Path: Or “Common Gold Path” is the path of travel that placer gold takes as it is
moved down river by the force of the water- usually during massive floods.
Good Gold: Well truthfully, there is no bad gold! But good gold is sometimes called
making wages or better while mining. There is a point at which it is not worth continuing in the hole you are
dredging in (see profitability).
Grain: A unit of weight measurement. 480 grains equals 1 Troy
Gram: A unit of weight measurement. 31.1 grams equals one Troy
Gravel: Rocks that are anywhere from a half inch to three inches in
Grizzly: A plate of steel with holes punched in it, a screen or heavy
steel bars to force oversize materials to be rejected and only allow materials to pass through that are "Blank"
(the hole size, say 1 inch) minus. For example, a grizzly that has opening between the bars of 2
inches would leave a pile of 2 inch minus gravel, ready for further processing.
Gut: The deepest part of a creek or river, usually near the
Hard Pack: Gravels that have not been disturbed since being deposited
there during some long ago storm or flood. They are very tight and require some use of pry bars or to dredge
Header Box: Sometimes known as the “bang box” or "crash box" (due to the noise of
gravel banging around inside) and was used on older dredges before the Jet Flair became popular. It is the area
that the rocks and water enter after leaving the dredge hose before entering the sluice box. Its job is to slow
down the material to allow the gold to “fall out” and get trapped in the sluice.
Hookah: Type of diving system whereby the diver is supplied breathable air through a
hose from a compressor on the surface, usually powered by the dredge pump engine but can be a stand alone unit,
sometimes powered by low voltage. A low pressure regulator is used for breathing. The diver is "tethered" to the
compressor, but can stay under water as long as the compressor is running. This is the most common
Hungarian Riffles: A series of bars placed in the sluice box perpendicular to the flow
of the water designed with a bend in them that creates a low pressure area down stream of the water flow to
allow more gold and heavy minerals to be extracted from the flow of water and gravel through the sluice
Iron bar: Tool for prying open bedrock pieces, prying boulders loose,
Jet Flair: The transition tube between the dredge's round suction
hose and the opens up an oval shape as it enters the sluice box.
Lode: Rock that contains one or more valuable minerals but needs
processing to extract the "Values".
Micron Gold: Gold too small to separate from the concentrates without using
amalgamation, shaker table or chemical leaching methods.
Mining Claim: See "Claim"
Mother Lode: The fabled elusive "Fabulously Rich" lode that the
California '49ers thought existed in the High Sierra mountain range which has turned out (so far) to be just
that: a fable. But we keep looking! :)
Nozzle: The metal fitting that is clamped on the the business (suction) end of
the dredge hose.
Nit picking: When the
Nugget: A piece of noble metal (i.e.. Gold, Silver, Platinum, etc.) that will not pass
through a number 10 screen.
Panning: The process used to separate gold from common river sand and
gravel. Gravel is placed in a pan, shaken and moved back and forth to remove the lighter materials.
This method has been used for centuries to sample gravel to determine if the area warrants further investigation
or mining. Also used to trace a placer deposit to it's lode source.
Pay: The term describing the amount the gravel you are mining is
yielding. For example, the location my friend told me he was dredging was "paying" a quarter ounce a day in
Paydirt: The dirt or gravel that contains higher concentrations of gold
and/or other values than the surrounding materials.
Pay Layer: Gravel bars often have layers that are deposited during flood
stage. These layers often act as a false bedrock with the gold being deposited around the old cobbles and
boulders that were there previously.
Pennyweight: Equal to the weight of one penny in the British Empire. It takes twenty
Pennyweight to make one troy ounce.
Platinum Group Metals:
Plug-up: When the dredge hose gets partially or completely clogged with rocks
and/or sand and gravel.
Pontoon: Floatation device to build a foundation in the water for the dredge
Profitability: The point at which you can pay your expenses with the equipment and crew you
have assembled- in the location you are dredging.
Purge Valve: A one-way valve allowing air to pass one direction and does not allow
water in. Used on better Dive Masks and snorkels.
Recovery System: This varies widely in design, but any system that is design to
catch and retain gold or other precious metals or gems.
S.C.U.B.A.: Self Contained Underwater Breathing Apparatus. This allows the
diver more freedom to roam under water but due to the bulky tank and other gear is usually not practical for
Snorkel: A tube held in the mouth while floating face down in the water to
allow you to breath without lifting your face out of the water.
Streak: See- Paystreak
Tailings: The waste material that drops back in the river after working it's
way through the dredge system or other mining gear.
Tracking/ back tracking:
Trommel: Circular metal tube with holes punched in it. This is to allow the smaller
particles to drop through as the "paydirt" is run through with water as a slurry. The oversize cobbles and
gravel run on through as tailings. Watch for cobbles with stringers of gold going into the tailings! A metal
detector mounted in the system could be useful to alert the operator of these
Troy Weight System:
Underwater rock weight:
Up cropped bedrock: A chunk or mass of bedrock extending up through the bottom of the stream
bed which can cause gold to accumulate in one glory hole or can enhance a paystreak if it occurs on the common
gold path traveling down the river.
Wet Suit Heater: (not the hot chocolate you drank before the