Mining Dictionary

Frequently Used Mining Terms

Adit-Tunnel on a vein or lode.

Hardrock Mine

Alluvium- Clay, silt, sand, and gravel deposited by a body of running water during relatively recent geologic time. Includes flood plains, lake beds, and river deltas. Such deposits can contain heavy ores like gold, platinum, diamonds, and tin, which have been eroded and subsequently concentrated by the action of the river or stream.

Amalgam- Quicksilver and other metals, usually gold or silver.

Assay- A measure of the amount of an economic metal within an ore sample.

Ball Mill- Ore grinding device consisting of a rotating cylinder filled with steel balls. Crushed ore is placed in the cylinder and eventually ground as fine as sand-size.

Bedrock- Bed of metalliferous deposit; slate underlying auriferous gravel.

Gold Deposition 1

Blind Lode- Shows no surface outcroppings.

Blossom Rock- Float ore found upon surface or near outcropping lod es.

Breasting- Taking ore from mine face or drift head.

Bullion- Gold, silver uncoined, pure refined metal.

Cage- Elevator to lower and hoist ore cars, men and materials.

Chute- An opening used to pass ore into mine cars.

Claim- Land held by a prospector or mining company for the purpose of mineral exploration. The holder of a claim is generally granted rights to the land in exchange for an agreement to spend a given amount of money on exploratory work.

Classifier- A machine or device that separates minerals on the basis of given criteria, often size and density.

Contact Lode- Lies beween two kinds of rock, e.g. porphyry and slate.

Country Rock- On either side of lode or ledge, usually barren;permanent rock enclosing vein.

Crosscut- Drift run at right angle to ledge go ascertain its width and otherwise prospect it; an opening or level driven across ground from one vein to another.

Deposit- Body of ore distinct from ledge; pocket of gravel or pay dirt.

Drifts- tunnels leading from main shaft or from other tunnels or levels through and along vein.

Dump- Place to deposit ore after taking from mine; pile of ore or waste rock.

Dyke- A long and relatively thin body of igneous rock that, while in the molten state, intruded a fissure in older rocks.

Face- Extreme end of tunnel, drift or excavation.

Float Rock- Fragments of lode floated by water or carried down by other means.

Flume- Box or piping to convey water.

Flux- Any substance used to promote fusion of metals.

Free Gold- Gold easily separated from quartz or dirt.

Gangue- Matrix. Quartz is commonly called gangue rock of gold and silver ores; may be other.

Gravity Separation- Recovery of gold from crushed rock or gravel using gold’s high specific gravity to separate it from lighter material.

Grubstake- Finances or supplies of food, etc., furnished to a prospector in return for an interest in any discoveries made.

Hanging Wall- Upper wall; rock or wall resting on lode or vein. The wall or rock on the upper or topside of an ore deposit.

High-Grader- One who steals rich ore, especially gold, from a mine.

Horse- Mass of wall rock or other barren material obtruding into an unbearing lode or fissure.

Incline- A slanting shaft.

Jig- A piece of milling equipment used to concentrate ore on a screen submerged in water, either by the reciprocating motion of the screen or by the pulsation of water through it.

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.

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

Ledge- Synonymous with lode or vein.

Level- Drifts from main shaft or one to another.

Lithology- The character of a rock described in terms of its structure, color, mineral composition, grain size, and arrangement of its component parts; all those visible features that in the aggregate impart individuality of the rock. Lithology is the basis of correlation in coal mines and commonly is reliable over a distance of a few miles.

Locate- To establish possessory right to claim; property secured designated “claim” or “location”.

Lode- A longitudinal fissure or chasm filled with ore-bearing matter and having well defined side walls; lode, vein and ledge are synonymous; a mineral vein in country rock.

Metallurgy- The study of extracting metals from their ores.

Mine- Comprises certain amount of territory on a lode or vein, together with shafts and machinery.

Muck- Ore or rock that has been broken by blasting.

Petering- Pinching or giving out of ore body.

Placer- Alluvial and other deposits; earth containing gold.

Porphyry- A barren ore, stratisfied reddish, purple or greenish rock, crystal embedded.

Quicksilver- Mercury

Reducing- Separating from foreign substances; reduction of ores is extracting them from the metals contained.

Reserves- Vein material still standing in mine.

Retort- Bullion extracted from amalgam by placing latter in cast iron retort, expelling quicksilver by heat.

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.

Schist- Clay slate.

Shaft- Vertical or incline excavation for prospecting or working mines.

Slag- Scum, dross; waste from smelters.

Sloughing- The slow crumbling and falling away of material from roof, rib, and face, sloughing in.

Sluice- box or trough for washing placer gravel.

Sodium Cyanide- A chemical used in the milling of gold ores to dissolve gold and silver.

Specific Gravity- The weight of a substance compared with the weight of an equal volume of pure water at 4 degrees Celsius.

Spot Price- Current delivery price of a commodity traded in the spot market, also called the cash price

Stamp Mill- machine for crushing ore by the weight of constantly falling pieces of iron, stone, or wood. The action approximates the pulverizing of material with a mortar and pestle.

Stopes- Ore stopes same as ore breasts, except that former means ore overhead or underneath, the latter in front or on the sides.

Streak- A diagnostic characteristic of minerals, where scratching a sample on a piece of unglazed porcelain leaves powder of a characteristic color.

Strike- A find of valuable mineral deposit. The direction, or bearing from true north, of the line of intersection of a mineral deposit or vein with the horizontal plane. The strike of a bed is the direction of a straight line that connects two points of equal elevation on the bed.

Stringer- A narrow vein or irregular filament of a mineral or minerals traversing a rock mass.

Stull- Timber platforms between levels.

Sulphuret- Sulphur combined with metallic, earthy or alkaline base.

Sump- The bottom of a shaft, or any other place in a mine, that is used as a collecting point for drainage water.

Tailings- Auriferous earth once washed.

Telluride- A chemical compound consisting of the element tellurium and another element, often gold or silver.

Tributors- Miners paying percentage of ore.

TommyKnocker- Miners who have been trapped in cave-ins and pound on the rocks for rescue. It is believed that the ghosts of these miners go on knocking in the mine shafts long after the victims have died.

 

Troy Ounce- unit of measure for precious metals. 1 troy ouce equals 31.1034768 grams.

Upraise- Running a drift upwards.

Vein- An opening, fissure, or crack in rock, containing mineralized material.

Visible Gold- Native gold which is discernible, in a hand specimen, to the unaided eye.

Wall- Boundary of vein and enclosing same.

Winze- Shaft connecting one drift or level with another, but not reaching the surface.