The Periodic Table Podcast:

Acidic precipitation: Snow and rain with a low pH, caused by industrial atmospheric emissions.

Acidic rocks: Igneous rocks high in silica.

Acid mine drainage: Acidic runoff water from mine waste dumps and mill tailings.

Adit: A horizontal mine access.

Aerial magnetometer: Measures magnetic field strength from an airplane.

Aeromagnetic survey: A geophysical survey done using magnetometers on aircraft.

Agglomerate: A rock made of volcanic fragments.

Agglomeration: Concentrating minerals based on adhesion properties.

Agitation: In metallurgy, the act of stirring or shaking.

Airborne survey: A survey from an aircraft to obtain data.

Alloy: A compound of multiple metals.

Alluvium: Sedimentary deposits laid down in certain environments.

Alpha meter: Measures positively charged particles from radioactive materials.

Alpha ray: Positively charged particle from certain radioactive materials.

Alteration: Physical or chemical rock change post-formation.

Amorphous: Rocks or minerals without a definite crystal structure.

Amortization: Systematic writing off of account balances.

Amphibolite: A rock mostly made of amphibole and plagioclase.

ANFO: Blasting agent used in many mines.

Annual report: Yearly corporate financial and operational report.

Anode: A metal plate used in electrolytic refining.

Anomaly: Indication of mineralization in underlying bedrock.

Anthracite: A hard, black coal.

Anticline: An arch or fold in rock layers.

Apex: The top of a vein or its closest surface point.

Ash: Residue after coal ignition.

Assay: Chemical test to determine ore metal content.

Assessment work: Work needed to keep legal control of mining claims.

Authorized capital: Refers to capital stock.

Autogenous grinding: Ore grinding using large ore pieces.

Back: Ceiling or roof of an underground mine opening.

Backfill: Waste material filling the void after ore extraction.

Background: Minor radioactivity due to cosmic rays or residual radioactivity.

Ball mill: A cylinder filled with steel balls to crush ore.

Basalt: A dark volcanic rock.

Basement rocks: Older or underlying rock mass.

Base metal: Non-precious metals.

Batholith: A large igneous rock mass.

Bauxite: The main ore of aluminum.

Bear market: When share prices are decreasing.

Bedding: The layering of sedimentary rocks.

Beneficiate: To concentrate or enrich ores.

Bessemer: Low-phosphorus iron ore.

Biotite: A magnesium-iron mica.

Bit: Cutting end of a drill.

Blackjack: Another term for sphalerite.

Blaster: Person responsible for detonating blastholes.

Blast furnace: A vessel for chemical ore reduction.

Blister copper: Crude copper before refining.

Block caving: A mining method involving large ore blocks.

Bull market: When share prices are rising.

Bullion: Metal formed into bars.

Byproduct: Secondary product recovered in processing.

Cable bolt: A support in unstable ground.

Cage: Elevator used in a mine shaft.

Calcine: Concentrate ready for smelting.

Call: An option to buy shares.

Capitalization: Value markets put on a company.

Capital stock: Total ownership of a company.

Carbon-in-pulp: Gold recovery method.

Cash flow: Net inflow/outflow of cash during a period.

Cathode: Metal plate produced by electrolytic refining.

Cesium magnetometer: Geophysical instrument to measure magnetic fields.

Chalcocite: A copper sulphide mineral.

Chalcopyrite: Most important copper ore mineral.

Channel sample: Sample taken from a trench.

Chartered bank: A financial institution for deposits and loans.

Chromite: Chief ore mineral of chromium.

Chute: Opening for ore drawing in a stope.

Cinnabar: A red ore mineral of mercury.

Claim: A land portion held by a prospector or mining company.

Classifier: A mineral-processing machine for size and density.

Clay: Fine-grained material made of hydrous aluminum silicates.

Cleavage: A mineral’s tendency to split.

Closed circuit: Loop in the milling process.

Coal: A carbonaceous rock mined for fuel.

Collar: Timbering or concrete around a shaft mouth.

Decline: A downward underground opening, inclined from the horizontal.

Deduction: An amount deducted from the gross weight of ore for impurities.

Dewatering: The process of removing excess water.

Diamond drill: A drill that cuts by abrasion using embedded diamonds.

Dike: A rock formation that intrudes into a plane.

Dilution: The waste, which is mixed with ore in mining.

Dip: Angle of the beds or layers relative to the horizontal.

Disseminated: Small particles of ore mineral spread through rock.

Drag fold: The result of plastic deformation.

Drift: A horizontal or nearly horizontal underground passage.

Drill-indicated reserves: The amount of reserves calculated by measurements.

Dyke: A long and thick wall of rock, often igneous.

Electrolysis: Process to extract metals.

Electromagnetic survey: A geophysical survey using variations in the Earth’s electromagnetic field.

Elevated gold values: Gold values that are higher than the normal levels.

Epithermal deposit: A mineral deposit occurring near the Earth’s surface.

Exploration: Prospecting, sampling, mapping, diamond drilling to estimate ore reserves.

Exploitation: Extracting minerals from the Earth.

Extrusive: Igneous activity that occurs at the Earth’s surface.

Face: The end of a drift, crosscut, or stope where work is taking place.

Fault: A break in the Earth’s crust.

Feasibility study: A detailed study to determine the viability of a mining project.

Feldspar: A group of crystalline minerals.

Ferrous: Containing iron.

Flotation: A process used to separate mineral particles.

Flow-through shares: Shares in an exploration company.

Flux: A compound added to a smelted material.

Fold: A bend in rock layers.

Free milling: Ores that can be treated and the gold extracted by direct cyanide leaching.

Gabbro: A dark, coarse-grained igneous rock.

Galena: Lead sulfide, the most common ore mineral of lead.

Gangue: The waste minerals in an ore deposit.

Geiger counter: An instrument used to measure the radioactivity.

Geochemistry: The study of the chemical properties and processes of Earth.

Geology: The science of studying the Earth’s structure.

Geophysics: The study of the physical properties of the Earth.

Geothermal energy: Energy derived from the Earth’s internal heat.

Gneiss: A layered or banded crystalline rock.

Gold loan: A form of debt financing for gold mining companies.

Graben: A block of the Earth’s crust that has dropped relative to surrounding blocks.

Gravity meter: An instrument to measure the gravitational field of the Earth.

Gyratory crusher: A machine that crushes ore by an eccentrically gyrating spindle.

Haulage: The transport of mined material.

Head grade: The average grade of ore fed into a mill.

Heap leaching: A process to extract precious metals from ore by placing the crushed ore on a pad in a heap.

Hematite: An oxide of iron, and one of the most common ore minerals.

High-grader: A worker who steals high-grade ore.

Hydrothermal: Relating to hot fluids circulating in the Earth’s crust.

Igneous: Rocks that solidified from a molten state.

Ilmenite: An ore mineral of titanium.

Induced polarization: A method to measure the resistivity of the Earth.

Inferior grade: Relatively low-grade ores.

In situ: In the natural or original position.

Intrusion: A body of igneous rock that has forced its way into pre-existing rocks.

Jaw crusher: A machine to break rock between two steel jaws.

Jig: A machine to concentrate ore by the pulsation of water.

Joint: A fracture dividing rock into two blocks without any offset.

Kimberlite: A volcanic rock, potentially diamond-bearing.


Kyanite: A metamorphic mineral used to make porcelain.

Lagging: Planks or small timbers placed between steel ribs along mine walls.

Lateral: A horizontal underground passage.

Launder: A chute or trough for conveying pulp or ore.

Lava: Molten rock that comes out of a volcano.

Leaching: A chemical process by which a solute is extracted into a solvent.

Magma: Molten rock beneath the Earth’s surface.

Magnetite: An oxide of iron and an important ore of iron.

Manway: A drift used exclusively for the movement of personnel.

Matrix: The fine-grained mass of material in which larger grains, crystals, or minerals are embedded.

Metallurgy: The science and study of the behaviors and properties of metals and their extraction from their ores.

Metamorphism: The change or alteration in a rock caused by external conditions.

Mill: A plant where ore is processed and treated.

Mineral: A naturally occurring homogeneous substance with a definite chemical composition.

Mineralization: The deposition of metals in rock from hydrothermal fluids.

Muck: Loose material in mines, often referring to ore or waste.

Nugget: A small mass of precious metal, usually gold, found free in nature.

Native metal: A metal found in nature in its pure state, not combined with other elements.

Ore: A naturally occurring material that can be profitably mined.

Ore body: An aggregation of ore with sufficient concentration to make mining economically viable.

Outcrop: That part of a geologic formation or structure that appears at the surface of the Earth.

Overburden: Layers of soil and rock covering a coal or ore deposit.

Panning: The simplest method of separating gold from placer material.

Pegmatite: A coarse-grained igneous rock.

Permeability: The ability of a rock or soil to transmit water or other fluids.

Placer: A deposit of sand and gravel containing valuable metals.

Porphyry: A rock texture of relatively large crystals set in a finer-grained matrix.

Quarry: A place where rock or minerals are extracted from the surface.

Quartz: A mineral composed of silicon dioxide.

Reclamation: The restoration of a site after mining or exploration activity is completed.

Refractory ore: Ore that resists the action of chemical reagents in the normal treatment processes.

Reserves: The amount of ore in a deposit that can be economically mined.

Riffle: Bars, slats, or obstructions placed in a sluicing system to capture gold particles.

Sampling: Taking small pieces of rock from a deposit to determine its value.

Seam: A layer of ore or coal.

Shaft: A vertical or inclined excavation in rock for the purpose of providing access to an ore body.

Slag: The vitreous mass left as a residue by the smelting of metallic ore.

Stope: An excavation made in a mine to extract ore.

Tailings: Materials left over after the process of separating the valuable fraction from the ore.

Tunnel: An underground or underwater passage.

Uraninite: A radioactive, black, and gray mineral, an important ore of uranium.

Vein: A fissure or crack in rock filled by minerals.

Volcanic: Pertaining to the activities, structures, or rock types of volcanoes.

Waste: Unmineralized, or sometimes mineralized, rock that is not mined for a profit.

Winze: An internal shaft, or a hole sunk from a shaft or adit.

Xenolith: A fragment of country rock found in an intrusive igneous body.

Yield: The quantity of ore or metal produced in a specified period.

Zinc: A metallic element used primarily in alloys.

Zone: An area of rock with distinct physical characteristics or mineral content.