Reference

Minerals terms and definitions

Minerals and mining terms: geology and deposit types, resource reporting and project studies, mining and processing methods, rare earths and permanent magnets, minor metals, markets and supply security, deep-sea mining and ocean law, and lunar and space resources. These are general reference definitions, not tied to any one report.

277 terms · Updated 21 Oct 2026

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4E basis (4E)In Industry: A reporting basis for platinum-group metal output that counts platinum, palladium, rhodium and gold together.

A

AACE cost estimate classes (Class 4 estimate, Class 3 estimate, AACE 18R-97, AACE): The AACE International scale that grades capital cost estimates from Class 5 (concept, least accurate) to Class 1 (definitive). Accuracy bands narrow as engineering advances.
Abyssal plain (abyssal, abyssal zone): The flat, deep ocean floor, mostly 3,000–6,000 m down, where polymetallic nodules lie.
Alkaline intrusion (alkaline complex, peralkaline intrusion, peralkaline complex): A body of igneous rock unusually rich in sodium and potassium. Peralkaline intrusions can concentrate rare earths, zirconium and niobium, often with uranium and thorium.
AlNiCo magnet (AlNiCo, Alnico): An aluminum-nickel-cobalt magnet with excellent heat stability but low coercivity, used in sensors and instruments.
Alumina (aluminum oxide, Al₂O₃)In Industry: Aluminum oxide (Al₂O₃), the white powder refined from bauxite that is fed to aluminum smelters. About 2 t of alumina make 1 t of aluminum.
Ammonium paratungstate (APT): The main refined tungsten chemical and the industry's price benchmark, made by dissolving concentrate and crystallizing it. It is reduced to oxide and metal powder.
Anode slimes (anode slime, anode mud): The insoluble residue that collects under anodes during copper electrorefining, a source of gold, silver, tellurium and selenium.
Anorthosite (anorthite, plagioclase, plagioclase feldspar, ferroan anorthosite): A pale rock made mostly of plagioclase feldspar that forms the lunar highlands. Its calcium-rich form, anorthite (CaAl₂Si₂O₈), is the Moon's main aluminum source.
Antimony (antimony metal, antimony ingot, antimonial lead): A brittle metalloid used mainly as a flame-retardant additive, in lead-acid batteries, glass and ammunition primers. Metal is traded at ≥99.65% purity.
Antimony trioxide (Sb₂O₃)In Industry: The main industrial antimony compound, used chiefly with halogenated chemicals as a flame-retardant booster in plastics and textiles, and as a catalyst for PET plastic.
Apparent consumption: Production plus imports minus exports, adjusted for stock changes, used to estimate a country's use of a material.
Areas of Particular Environmental Interest (APEI, APEIs): Zones the International Seabed Authority sets aside from mining in the Clarion-Clipperton Zone to protect representative seabed habitat.
Artemis AccordsIn Aerospace: Non-binding principles for civil space exploration, led by the US, covering transparency, interoperability, sharing of scientific data and avoiding harmful interference. Countries join by signing.
Artisanal and small-scale mining (ASM, artisanal mining): Informal, mostly manual mining by individuals and small groups. It supplies much of the world's tantalum and some cobalt and gold, with high safety and traceability risks.
Assay (assays, fire assay): A laboratory analysis that measures the metal content of a rock, concentrate or product sample.
Assessed price (price assessment, price reporting agency, Fastmarkets, Argus, Shanghai Metals Market, SMM): A price set by a price reporting agency from surveyed trades and offers, used for metals without liquid exchange futures, such as tungsten, antimony and rare earths.
Asteroid spectral types (C-type asteroid, S-type asteroid, M-type asteroid, C-type, S-type, M-type): Classes of asteroid by surface composition: C-type are carbon-rich and may hold water; S-type are stony; M-type appear metallic, rich in iron, nickel and possibly platinum group metals.

B

Basket price (PGM basket, basket price per ounce): The combined value of all metals a mine produces per unit of output, such as per 4E ounce for platinum group metal mines.
Bauxite: The main aluminum ore, a weathered rock rich in aluminum hydroxides. It is refined into alumina, and gallium can be recovered along the way.
Bayer process (Bayer liquor): The standard method for refining bauxite into alumina by dissolving it in hot caustic soda. Gallium can be recovered from its process liquor.
BeneficiationIn Finance: Processing that raises the value of ore by removing waste (gangue) minerals, producing a higher-grade concentrate and a waste stream called tailings. Crushing, grinding, flotation and magnetic separation are common steps.
Benthic (benthos, benthic fauna): Relating to the seafloor and the animals that live on or in it.
Bulk sample (bulk sampling): A large sample, often tens to thousands of tonnes, mined and processed to test how ore behaves at scale.
Bushveld Complex (Bushveld, Merensky Reef, UG2, UG2 Reef, Platreef): A huge layered intrusion in South Africa that holds most of the world's platinum group metal reserves. Its main ore layers are the Merensky Reef, the UG2 chromitite and the Platreef.
By-product credit (by-product credits, byproduct credit): Revenue from secondary metals that is subtracted from the cost of the main metal, lowering its reported unit cost.
By-product metal (by-product, byproduct, companion metal): A metal recovered only as a side stream of mining or refining another metal, such as gallium from alumina or indium from zinc. Its supply follows the main metal, not its own price.

C

Capital and operating costsIn Finance: Capital costs (capex) are the upfront spending to build or expand a project, such as the plant, equipment and mine development. Operating costs (opex) are the recurring costs of running it, often quoted per tonne of ore or per unit of product.
Carbonatite: A rare igneous rock made mostly of carbonate minerals. Carbonatites host many of the largest light rare earth deposits.
CarburizationIn Industry: Absorption of carbon into a metal surface at high temperature, which can harden it on purpose or embrittle it in service.
Care and maintenance (placed on care and maintenance): Status of a mine or plant that has stopped production but is kept in condition to restart when prices or conditions improve.
Cassiterite (SnO₂): Tin oxide (SnO₂), the main tin ore mineral, mined from veins and placers.
Cemented carbide (hardmetal, tungsten carbide, carbide tools): Tungsten carbide grains bound with cobalt into an extremely hard, tough material used for cutting tools, drill bits and wear parts.
Chinese antimony export controls (Announcement No. 33, Announcement No. 46, antimony export ban): China has required licences to export antimony ores, metal and oxides since 15 September 2024. A December 2024 policy of refusing US-bound licences was suspended in November 2025 for a year; exports for US military use stay barred.
Chinese rare earth export controls (MOFCOM Announcement No. 18, Announcement No. 18, Announcement No. 61, Announcement No. 70, rare earth export licensing): Since April 2025 China has required licences to export seven medium and heavy rare earths, including dysprosium and terbium, and their oxides, alloys and compounds. A wider October 2025 expansion was suspended in November 2025 for one year.
Chromitite (chromite): A rock made mostly of the chromium mineral chromite. Chromitite reefs such as UG2 carry platinum group metals but are harder to smelt.
Cislunar space (cislunar)In Aerospace: The region between Earth and the Moon, including lunar orbits. Interest in it is growing for exploration, commerce and military awareness.
Clarion-Clipperton Zone (CCZ, Clarion-Clipperton Fracture Zone): A vast Pacific abyssal region between Hawaii and Mexico holding the richest known nodule fields, where most seabed exploration contracts lie.
Co-productIn Sustainability: A useful output produced alongside the main product, such as soybean meal from crushing, glycerol from biodiesel, or propane and naphtha from HVO. Co-products share the upstream emissions through allocation or earn credits through system expansion.
Cobalt-rich ferromanganese crusts (ferromanganese crusts, cobalt crusts, cobalt-rich crusts): Thin metal-rich coatings on seamount rock, carrying cobalt, nickel, manganese and rare earths.
Coercivity (Hcj, intrinsic coercivity): A magnet's resistance to being demagnetized by opposing fields or heat. Heavy rare earths raise it.
Coltan (columbite-tantalite, tantalite, columbite): A dark ore mixing columbite and tantalite, minerals rich in niobium and tantalum. Much is dug by hand in central Africa.
Comminution (crushing and grinding, SAG mill, ball mill, grinding): Crushing and grinding ore to free mineral grains from waste. It is usually the largest energy user in a processing plant.
Common heritage of mankind (common heritage of humankind): The legal principle that certain resources, such as seabed minerals in the Area, belong to humanity as a whole and cannot be claimed by one state.
Concentrate (mineral concentrate, preconcentrate): The upgraded product of mineral processing, with much higher metal content than ore, sold to smelters or refiners. Tungsten concentrate is typically ≈65% WO₃.
Conflict minerals (3TG, conflict mineral): Minerals whose trade may finance armed groups or abuses, defined in US and EU rules as tin, tantalum, tungsten and gold, known as 3TG.
Contained metal (contained metal content, in-situ metal, gross in-situ value): The total metal in a deposit or product, found by multiplying tonnage by grade, before any losses in mining and processing.
Cost, insurance and freight (CIF)In Industry: A trade term in which the seller pays for goods, insurance and shipping to the destination port. Import duties are often calculated on CIF value.
Cracking (acid bake, sulfuric acid bake, caustic cracking, caustic conversion, acid digestion): Breaking down a rare earth or similar concentrate with strong acid or alkali so its metals can be dissolved. Sulfuric acid baking and caustic conversion are common routes.
Critical mineral (critical material)In Finance: A mineral or material considered essential to economic or national security whose supply is at risk of disruption. Governments publish official lists, such as the US Geological Survey critical minerals list.
Critical Raw Materials Act (CRMA, Regulation (EU) 2024/1252)In Batteries: The 2024 EU law, Regulation (EU) 2024/1252, on securing critical raw materials. Its 2030 benchmarks call for EU extraction of 10%, processing of 40% and recycling of 25% of EU needs, and no more than 65% from any one non-EU country.
Cryolite (Na₃AlF₆, smelting bath)In Industry: Sodium aluminum fluoride (Na₃AlF₆), the molten salt bath in which alumina is dissolved for smelting.
Curie temperature (Curie point): The temperature above which a magnetic material loses its magnetism. Working limits are set well below it.
Current efficiencyIn Industry: The share of electric current in an electrolytic cell that produces metal rather than being lost to side reactions. Modern aluminum cells reach ≈95%.
Cut-and-fill mining (drift-and-fill, cut and fill, backfill, paste backfill): An underground method that mines ore in horizontal slices and fills each void, often with cemented tailings, before taking the next slice.
Cut-off grade (cutoff grade): The lowest grade at which rock is counted as ore in a resource or mine plan. Rock below it is treated as waste.

D

De minimis rule (de minimis threshold, 0.1% rule): In export controls, a threshold below which a foreign-made product's controlled content is ignored; above it, the exporting country's controls apply.
Decomposition potential (decomposition voltage): The minimum voltage needed to split a compound by electrolysis. Oxides with higher values, such as calcium and magnesium oxide, are reduced last.
Deep Seabed Hard Mineral Resources Act (DSHMRA, commercial recovery permit, NOAA exploration licence, NOAA exploration license): A 1980 US law under which NOAA licenses US citizens to explore and mine the deep seabed beyond national jurisdiction. A January 2026 NOAA rule allows one combined application for both.
Defense Logistics Agency (DLA, DLA Strategic Materials)In Industry: The US Defense Department agency that buys supplies for the military. Its Strategic Materials office manages the National Defense Stockpile.
Defense Production Act Title III (DPA Title III, Defense Production Act)In Aerospace: A US authority that lets the Defense Department fund, lend to or guarantee domestic production of materials and components critical to national defense.
Delta-v (Δv, delta v)In Aerospace: The total change in velocity a spacecraft can achieve with its propellant, used as the budget for planning a mission. Reaching low Earth orbit from the ground takes ≈9.4 km/s once gravity and drag losses are counted.
DFARS (Defense Federal Acquisition Regulation Supplement)In Aerospace: The US Defense Department's supplement to the Federal Acquisition Regulation, adding defense-specific contract rules. Its clauses restrict sourcing of specialty metals, certain magnets and some Chinese-made components.
DFARS 252.225-7052 (252.225-7052, 10 U.S.C. 4872, 10 U.S.C. 2533c): The US defense contract clause barring NdFeB and samarium-cobalt magnets, tantalum and tungsten from China, Russia, Iran and North Korea. From 1 January 2027 it covers every stage from mining to finished product.
Dilution refrigeratorIn Computing: A cryogenic cooler that reaches a few thousandths of a degree above absolute zero by mixing two helium isotopes. Superconducting quantum computers run inside one.
Disseminated deposit (disseminated ore): A deposit in which ore minerals are scattered as fine grains through the host rock, rather than concentrated in veins. It is usually lower grade but suited to bulk mining.
Dissipative use (dissipative uses): A use that spreads a metal so thinly, as in pigments or flame retardants, that recovering it is impractical.
Dodd-Frank Section 1502 (Section 1502, Form SD, Conflict Minerals Report, Conflict Minerals Rule): The 2010 US law requiring SEC-reporting companies to check whether their 3TG comes from the DRC or neighbors and disclose it each year on Form SD.
Drift (adit): A horizontal underground tunnel used for access, haulage or exploration.
Dual-use (dual-use technology, dual-use goods)In Aerospace: Describes goods, software and technology with both civilian and military uses, such as drones, machine tools and some chips. They are controlled under regimes such as the EAR and the Wassenaar Arrangement.
Dysprosium and terbium (dysprosium, terbium, DyFe): Heavy rare earths added to NdFeB magnets to keep them strong at high temperatures, as in electric vehicle motors. Supply is concentrated in China and Myanmar.

E

Electrorefining (electrolytic refining): Purifying a metal by dissolving an impure anode and plating pure metal onto a cathode.
ElectrowinningIn Industry: Recovering pure metal from a solution by passing current through it, so the metal plates onto cathodes. It is a final step in many hydrometallurgical plants.
Ellingham diagram (Ellingham ordering): A chart of how stable metal oxides are at different temperatures, used to predict which oxides a reducing agent or electrolysis cell will split first.
Entity List (BIS Entity List)In Computing: A US Commerce Department list of foreign companies and organizations that need a license to receive US-controlled items, which is usually denied. Many Chinese chipmakers are on it.
EPA (U.S. Environmental Protection Agency)In Sustainability: The federal agency that runs the Renewable Fuel Standard and its lifecycle analysis, including ILUC.
EU Conflict Minerals Regulation (Regulation (EU) 2017/821, EU 2017/821): Regulation (EU) 2017/821, which since 1 January 2021 requires EU importers of 3TG above set volumes to carry out supply-chain due diligence.
Ex-China price (ex-China, China domestic price, price bifurcation): The price of a material sold outside China, which can sit far above China's domestic price when export controls split the market.
Exclusive economic zone (EEZ, EEZs): The sea out to 200 nautical miles from a country's coast, where it holds rights over fishing, energy and seabed minerals.
Exploration and exploitation licences (exploration licence, exploitation licence, exploitation license, mining licence, mining license, concession): Government permits that first allow searching for minerals in an area and later allow mining them. In Greenland and many civil-law countries an exploitation licence is the mining permit.
Exploration contract (ISA exploration contract, plan of work, exploitation plan of work): An International Seabed Authority contract giving a sponsored contractor exclusive rights to explore a seabed area for a set mineral, usually for 15 years.

F

Feasibility study (DFS, definitive feasibility study, bankable feasibility study): The most detailed engineering and economic study of a mine before a construction decision, used to raise project finance. Bankable or definitive versions carry the tightest cost estimates.
Ferrite magnet (ferrite, ceramic magnet, hard ferrite): A cheap, rare-earth-free ceramic magnet made of iron oxide with strontium or barium. It is far weaker than NdFeB but widely used.
Ferrosilicon (FeSi, FeSi75)In Industry: An alloy of iron and silicon, made in electric furnaces, used to remove oxygen from steel, to treat cast iron and to make magnesium. Grades are named by silicon content, such as FeSi75.
FFC Cambridge process (FFC-Cambridge, electro-deoxidation): A method that removes oxygen from a solid metal oxide by electrolysis in molten calcium chloride at ≈900–950 °C, producing metal powder and oxygen.
Fission surface powerIn Aerospace: A small nuclear reactor designed to power a base on the Moon or Mars, including through the ≈14-day lunar night when solar power is unavailable.
Fluorspar (fluorite, CaF₂, acidspar, acid-grade fluorspar): The mineral fluorite (calcium fluoride, CaF₂), the main source of fluorine for hydrofluoric acid, refrigerants and aluminum smelting. Acid grade is ≥97% CaF₂.
Foreign direct product rule (FDPR)In Aerospace: An EAR provision that extends US export controls to foreign-made items produced with certain US technology, software or equipment.
Foreign entity of concern (FEOC)In Batteries: A US legal category for companies tied to China, Russia, Iran or North Korea, used to bar them from clean-energy tax credits. The 2025 OBBBA law added broader prohibited foreign entity rules for most remaining credits.
Free on board (FOB, FOB China): A trade term in which the seller delivers goods onto the ship at the export port and the buyer pays freight and insurance from there.
Froth flotation (flotation, flotation circuit, cleaner circuit, scavenger circuit, depressant): Separating minerals by making the target grains repel water so they cling to air bubbles and float off as froth. Collectors, frothers and depressants control which minerals float.
Fusion energy (nuclear fusion, fusion power, deuterium-tritium fusion, D-T fusion)In Industry: Energy released when light nuclei, such as deuterium and tritium, combine at temperatures of over 100 million °C. It would produce little long-lived waste; commercial fusion power plants are still under development.

G

Gallium and germanium (gallium, germanium): By-product metals used in chips, optics and solar cells. Gallium comes mostly from alumina refining and germanium from zinc refining and coal ash.
Gangue (gangue minerals, waste rock): The worthless minerals mixed with ore minerals in rock, which processing separates and discards as tailings.
Grain boundary diffusion (GBD, grain-boundary diffusion): Applying dysprosium or terbium to a finished magnet's surface and heating it so they spread along grain edges. It raises heat resistance with far less heavy rare earth.
Grams per tonne (g/t): The usual grade unit for gold and platinum group metal ores. One g/t equals one part per million.
Gravity separation (gravity concentration, dense media separation): Separating minerals by density using jigs, spirals or shaking tables, common for tin, tungsten, tantalum and gold.
Greenfield and brownfield projects (greenfield, brownfield): A greenfield mine is built on an undeveloped site; a brownfield project expands or restarts an existing operation, usually with lower risk and cost.
Greenland Uranium Act (Act No. 20 of 2021, Uranium Act, Greenland uranium ban): Greenland's Act No. 20 of 2021, which bans prospecting, exploring for and mining uranium, including ores with more than 100 ppm uranium. It blocks some uranium-bearing rare earth deposits.
Greisen: Granite altered by hot fluids into quartz and mica, which can host tin and tungsten ores.

H

Hafnium: A metal always found with zirconium and separated during nuclear-grade zirconium production. It is used in superalloys, chip insulators and reactor control rods.
Hall-Héroult process (Hall–Héroult, aluminum smelting, aluminium smelting)In Industry: The standard method for making aluminum: alumina is dissolved in molten cryolite at ≈950 °C and split by electric current, with carbon anodes that burn and release CO₂.
Heavy mineral sands (mineral sands): Beach and dune sands rich in dense minerals such as ilmenite, rutile, zircon and monazite, mined for titanium, zirconium and rare earths.
Helium (liquid helium)In Industry: An inert gas recovered mainly as a byproduct of natural gas processing and liquefaction. Liquid helium, at ≈4 K, cools MRI and research magnets; the gas is vital for chipmaking, fiber drawing and leak testing.
Helium-3 (He-3, ³He, helium 3): A light, stable helium isotope implanted in lunar soil by the solar wind at parts-per-billion levels. It is sought for cryogenic cooling and proposed fusion fuel.
High-pressure acid leaching (HPAL, mixed hydroxide precipitate, MHP): Dissolving nickel and cobalt from laterite ore with sulfuric acid at high temperature and pressure. It yields intermediates such as mixed hydroxide precipitate for battery materials.
Host rock (host mineral): The rock that surrounds or contains a mineral deposit. Its size says nothing about how much metal the deposit holds.
Hydrogen reduction of ilmenite (ilmenite reduction): Heating ilmenite with hydrogen so it gives up oxygen as water, which is then split to make oxygen. It is one of the simplest lunar oxygen routes.
Hydrometallurgy (hydrometallurgical recycling, hydromet)In Batteries: Recovering metals by dissolving them in acid and separating them chemically. It recovers lithium as well as nickel and cobalt at high purity and is now the dominant recycling route.
Hydrothermal vein (quartz vein, vein deposit, hydrothermal deposit): A crack in rock filled with minerals deposited by hot water, often quartz carrying gold, antimony or tungsten.

I

IEA (International Energy Agency)In Sustainability: The Paris-based intergovernmental energy analysis body.
IEA scenarios (STEPS, Stated Policies Scenario, APS, Announced Pledges Scenario, NZE, Net Zero Emissions by 2050 Scenario): Outlook cases the International Energy Agency uses for energy and mineral demand. They include the Stated Policies Scenario, based on policies in place or detailed, the Announced Pledges Scenario and the Net Zero Emissions by 2050 Scenario.
Ilmenite (FeTiO₃): An iron-titanium oxide mineral (FeTiO₃), common in mare basalts and mineral sands. On the Moon it is a leading feed for making oxygen by hydrogen reduction.
In-situ recovery (ISR, in-situ leaching): Extracting metal by pumping a leaching solution through an ore body underground and recovering it from wells, without digging the rock. It is the main uranium mining method.
In-situ resource utilization (ISRU)In Aerospace: Making useful products, such as oxygen, water or propellant, from materials found on the Moon, Mars or asteroids, to cut what must be launched from Earth.
Indigenization (domestic substitution, import substitution)In Industry: Replacing imported technology or inputs with domestically made ones, often under government policy.
Indium and tellurium (indium, tellurium, indium tin oxide, ITO, cadmium telluride, CdTe): By-product metals: indium, recovered from zinc refining, goes into indium tin oxide screen coatings; tellurium, from copper anode slimes, goes into cadmium telluride solar cells.
Inert anode (oxygen-evolving anode, non-consumable anode)In Industry: An aluminum smelting anode made of ceramic, metal or cermet that is not consumed and releases oxygen instead of CO₂. It could remove direct smelting emissions but must survive the corrosive bath for years.
Infill drilling (infill drill program): Closely spaced drilling within a known deposit to raise confidence in its shape and grade, often to upgrade inferred resources.
International Seabed Authority (ISA, Seabed Authority, ISA Council, Legal and Technical Commission): The body set up under UNCLOS, based in Kingston, Jamaica, that grants exploration contracts and is drafting rules for mining in the Area.
Ion exchange (ion-exchange resin): Separating or purifying dissolved metals by passing a solution through resin beads that swap one ion for another.
Ion-adsorption clay (ionic clay, ionic adsorption clay, ion-adsorption deposit, IAC): Weathered clay in which rare earths are loosely held on clay surfaces and can be leached cheaply. Deposits in southern China and Myanmar supply most heavy rare earths.
ITAR (International Traffic in Arms Regulations)In Aerospace: The US State Department rules that control exports of defense articles, services and technical data on the US Munitions List. Sharing controlled data with a foreign person, even inside the US, can count as an export.
ITSCI (International Tin Supply Chain Initiative): The International Tin Supply Chain Initiative, a traceability and due diligence program that tags tin, tantalum and tungsten minerals from mine sites in central Africa.

J

JORC Code (JORC, JORC 2012, Australasian Joint Ore Reserves Committee): The Australasian code for public reporting of exploration results, mineral resources and ore reserves, used by companies listed in Australia and New Zealand. The current edition dates from 2012.

K

KREEP (KREEP basalt): Lunar material enriched in potassium (K), rare earth elements (REE) and phosphorus (P), concentrated around the Procellarum region.

L

Laterite (nickel laterite, lateritic ore): Iron-rich soil and rock formed by deep tropical weathering. Nickel laterites supply much of the world's nickel and some cobalt.
Layered mafic intrusion (layered intrusion, reef): A large body of iron- and magnesium-rich magma that cooled in layers, concentrating chromium, platinum group metals and nickel into thin, continuous ore layers called reefs.
LBMA (London Bullion Market Association, London OTC market): The London Bullion Market Association, which sets trading and refining standards for the London over-the-counter market in gold, silver, platinum and palladium.
Leaching (acid leaching, bioleaching)In Batteries: Dissolving metals out of a solid, such as black mass or ore, with acid or another solution. It is the first chemical step in hydrometallurgy.
Liberation (mineral liberation): The degree to which grinding frees valuable mineral grains from gangue so they can be separated.
Life of mine (LOM, mine life): The planned operating span of a mine, from first production until reserves are exhausted under the mine plan.
Light and heavy rare earths (light rare earths, heavy rare earths, LREE, LREEs, HREE, HREEs, medium rare earths): Rare earths are grouped by atomic weight. Light ones, such as lanthanum, cerium, neodymium and praseodymium, are more abundant; heavy ones, such as dysprosium, terbium and yttrium, are scarcer and costlier.
Lithium carbonate equivalent (LCE)In Batteries: A common unit for comparing lithium content across compounds, expressed as the mass of lithium carbonate that would contain the same lithium. One tonne of lithium metal equals ≈5.3 tonnes LCE.
Locked-cycle test (locked cycle test): A laboratory flotation test that recycles middle streams over several runs to predict steady-state plant recovery and grade.
London Metal Exchange (LME): The main exchange for industrial metal futures and warehouse delivery, setting benchmark prices for copper, aluminum, nickel and zinc.
Lunar regolith (regolith, lunar soil, lunar dust): The layer of loose dust and broken rock covering the Moon, the main feedstock for making oxygen, metals and building material in place.

M

Magnet grade (magnet grades, N52, N42): A code for a magnet's strength and heat rating. In NdFeB grades such as N52 or 38EH, the number gives energy product and the suffix the temperature class.
Magnet powder processing (strip casting, hydrogen decrepitation, jet milling, aligned pressing, vacuum sintering): The main steps in making sintered magnets. The alloy is strip cast into flakes, cracked by hydrogen decrepitation and jet milled to a few microns, then pressed in a magnetic field and vacuum sintered.
Magnet recycling (magnet-to-magnet recycling, HPMS, hydrogen processing of magnet scrap, HDDR): Recovering rare earths from scrap magnets, either by dissolving them chemically or by hydrogen processing that turns old magnets directly into powder for new ones.
Magnetic separation (magnetic separator): Separating minerals by how strongly they respond to a magnet, used to upgrade iron ores, mineral sands and rare earth ores.
Mare and highland regolith (mare, maria, lunar highlands, mare basalt): Mare regolith covers the dark basalt plains and is rich in iron and titanium; highland regolith covers the pale uplands and is rich in aluminum and calcium.
Master alloy (master alloys): A concentrated alloy of a key element, such as dysprosium-iron, added to a melt to control its composition.
Matte (PGM-rich matte, nickel matte)In Industry: A molten mix of metal sulfides produced in smelting, from which copper, nickel or platinum-group metals are later refined.
Maximum energy product (BHmax, (BH)max, energy product, MGOe): The headline measure of a magnet's strength, the peak product of flux density and field, in MGOe or kJ/m³. Top NdFeB grades exceed 50 MGOe.
Metallization (metallisation, oxide-to-metal conversion): Converting purified rare earth oxides into metal or alloy, by molten salt electrolysis or metallothermic reduction. It is a narrow bottleneck outside China.
Metallothermic reduction (calciothermic reduction, magnesiothermic reduction): Producing a metal by reacting its oxide or halide with a more reactive metal such as calcium or magnesium. It is used for samarium, dysprosium, terbium and titanium.
Metallurgical recovery (recovery, plant recovery, metal recovery): The share of metal in the feed that ends up in saleable product. Recovery and grade together set how much metal a plant produces.
Metric tonne unit (mtu, MTU, metric ton unit): The price unit for tungsten concentrate and APT: 10 kg of WO₃, containing ≈7.93 kg of tungsten.
Military specification (MIL-SPEC, mil-spec, MIL-STD)In Industry: A US defense standard defining the properties, testing and packaging a material or product must meet for military purchase.
Mine permitting (plan of operations, notice-level activity): Approvals needed to explore, build and operate a mine, such as environmental reviews, water and air permits and operating plans. On US federal land, larger disturbance needs an approved plan of operations.
Mine-to-magnet (mine to magnet): A supply chain that covers every step from mining and separation through metal, alloy and finished magnets, often within one country or group.
Mineral reserves vs. resourcesIn Finance: A mineral resource is a concentration with reasonable prospects of eventual economic extraction, classed as inferred, indicated or measured. A mineral reserve is the part of indicated and measured resources shown to be economically mineable by at least a pre-feasibility study, classed as probable or proven.
Minerals Security Partnership (MSP): A US-led group of governments, launched in 2022, that coordinates investment in critical mineral projects outside China.
Mining Code (exploitation regulations, ISA Mining Code, draft exploitation regulations): The International Seabed Authority's set of rules for seabed exploration and exploitation. Exploration rules exist, but exploitation regulations were still unadopted after the July 2026 session.
Mining dilution (dilution, ore dilution): Waste rock that ends up mixed with ore during mining, lowering the grade sent to the mill.
Mining royalty (royalty, royalties, sliding-scale royalty, net smelter return royalty, NSR royalty): A payment to a government or landowner based on the value or volume of minerals produced. Sliding-scale royalties rise with the metal price.
Minor metals (minor metal, technology metals): Metals produced in small volumes, often as by-products and without exchange-traded futures, such as gallium, germanium, indium, tellurium, rhenium and hafnium.
Mississippi Valley-type deposit (MVT, MVT deposit): A lead-zinc deposit formed by warm basin brines in carbonate rock, named after the US region where it was first described.
Mixer-settler (mixer-settlers, countercurrent cascade): A tank pair in solvent extraction where two liquids are mixed and then allowed to separate. Rare earth plants link hundreds in countercurrent cascades.
Modifying factors: The mining, processing, economic, legal, environmental and social factors applied to convert a mineral resource into a reserve.
MOFCOM (Ministry of Commerce of China, China Ministry of Commerce): China's Ministry of Commerce, which issues export-control announcements and licenses exports of controlled minerals, materials and technologies.
Molten regolith electrolysis (MRE, molten oxide electrolysis, MOE): Melting regolith at ≈1,600 °C and passing current through it to release oxygen at the anode and metals such as iron and silicon at the cathode, with no added salts.
Molten salt electrolysis (fused salt electrolysis, molten-salt electrolysis): Producing a reactive metal by passing current through its compound dissolved in molten salt. Neodymium and didymium metal are made this way.
Moon Agreement (Moon Treaty, Agreement Governing the Activities of States on the Moon and Other Celestial Bodies): A 1979 UN treaty declaring lunar resources the common heritage of mankind. Few states have joined, and none of the major spacefaring powers.

N

National Defense Stockpile (NDS, strategic stockpile)In Industry: The US government's reserve of strategic and critical materials, held for national defense emergencies and bought and sold by the Defense Logistics Agency.
National space resources laws (Luxembourg space resources law, space resources law): Laws that let companies own resources they extract in space, adopted by Luxembourg in 2017, the UAE in 2019 and Japan in 2021, alongside the 2015 US law.
NdFeB magnet (NdFeB, neodymium magnet, neodymium-iron-boron, Nd₂Fe₁₄B, neo magnet): A neodymium-iron-boron permanent magnet, the strongest commercial type. It powers most electric vehicle motors, wind generators and robots but weakens at high temperature without dysprosium or terbium.
NdPr (NdPr oxide, neodymium-praseodymium, didymium, PrNd): A mixed neodymium-praseodymium oxide or metal, the main rare earth input to NdFeB magnets and the industry's price benchmark. Didymium is the metal form.
Near-Earth asteroid (NEA, NEAs, near-Earth object): An asteroid whose orbit brings it close to Earth's. Some can be reached with less energy than the Moon's surface.
NEPA (National Environmental Policy Act)In Aerospace: The US National Environmental Policy Act, which requires federal agencies to assess environmental effects before major actions, such as licensing a launch site or a higher flight rate.
Net import reliance (import reliance, net import dependence): The share of a country's apparent consumption of a material met by net imports. The USGS reports it each year for every major mineral.
Net present value (NPV) in miningIn Finance: The sum of a project's future cash flows discounted to today, minus its upfront cost. In mining studies it is the headline figure, usually after tax at a stated discount rate such as 8%, and it moves sharply with commodity price assumptions.
NI 43-101 (National Instrument 43-101, 43-101 technical report, CIM Definition Standards, CIM): Canada's rule for disclosing scientific and technical information about mineral projects. Reports must be prepared by a qualified person and follow CIM definitions.
Nodule collector (collector vehicle, collector, riser, riser system, lift system): A seabed vehicle that picks up nodules and pumps them through a riser pipe to a surface ship. The riser and flexible hoses link the two.

O

OECD Due Diligence Guidance (OECD Due Diligence Guidance for Responsible Supply Chains of Minerals, OECD guidance, OECD 3TG supplement): The OECD's framework for responsible mineral supply chains from conflict-affected and high-risk areas, the reference standard behind US and EU conflict minerals rules.
Office of Strategic Capital (OSC)In Aerospace: A US Defense Department office, created in 2022, that makes loans and loan guarantees to companies producing critical technologies.
Old and new scrap (old scrap, new scrap, home scrap, post-consumer scrap): Old scrap comes from products at the end of their life; new scrap is offcuts and rejects from manufacturing, which are easier to recycle.
Open-pit mining (open pit, open-cut mining, surface mining, strip mining): Surface mining from a large excavation dug in benches. It suits large, near-surface deposits and moves more waste than ore.
Ore (ore body, orebody): Rock containing enough of a valuable mineral to be mined and processed at a profit. Whether rock counts as ore depends on prices and costs, not geology alone.
Ore grade (grade, head grade, feed grade): The concentration of a valuable metal or mineral in ore, given as a percentage, in grams per tonne or in parts per million. Higher grade means more metal per tonne mined.
Ore sorting (sensor-based ore sorting): Using sensors such as X-ray or optical scanners to reject waste rock from ore before grinding, cutting processing cost.
Outer Space TreatyIn Aerospace: The 1967 UN treaty that underpins space law. It bars national claims of sovereignty over celestial bodies and weapons of mass destruction in orbit, and makes states responsible for their companies' space activities.
Overburden (prestrip, pre-stripping): Soil and rock lying above an ore body that must be removed before surface mining.

P

Pegmatite (pegmatites): A very coarse-grained igneous rock formed from the last, element-rich melt of a magma. Pegmatites host many lithium, tantalum and niobium deposits.
Permanent magnet (permanent magnets, rare earth magnet, rare earth magnets, REPM): A material that stays magnetized without power, used in motors, generators, speakers and sensors. Rare earth magnets are the strongest.
Permanent magnet synchronous motor (PMSM, PMSG, permanent magnet motor, externally excited synchronous motor, EESM, wound-rotor motor): An electric motor with permanent magnets in its rotor, the most efficient and common type for electric vehicles. Wound-rotor and induction motors avoid rare earths.
Permanently shadowed regions (PSR, PSRs, cold traps, permanently shadowed craters): Polar craters on the Moon that never receive sunlight and stay below ≈110 K, cold enough to trap water ice and other volatiles.
Phosphate rock (phosphorite)In Industry: Sedimentary rock rich in phosphate minerals, mined chiefly in Morocco and Western Sahara, China and the US. It is the raw material for phosphate fertilizer.
Placer deposit (placer, alluvial deposit, placers): Heavy minerals such as gold, tin or zircon concentrated by rivers, waves or wind in sand and gravel.
Platinum group metals (PGM, PGMs, platinum-group metals)In Industry: Six rare metals found together in ore: platinum, palladium, rhodium, ruthenium, iridium and osmium. They are prized as catalysts and are mined mainly in South Africa and Russia.
Polymetallic nodules (manganese nodules, nodules, polymetallic nodule): Potato-sized lumps on the abyssal seafloor rich in manganese, nickel, copper and cobalt, formed over millions of years. The Clarion-Clipperton Zone holds the largest fields.
Porphyry copper deposit (porphyry, porphyry deposit): A very large, low-grade copper deposit formed around a cooling igneous intrusion. Porphyries supply most of the world's copper and much of its molybdenum and rhenium.
Pre-feasibility study (PFS)In Finance: An intermediate engineering and economic study that tests whether a mineral project is viable and selects the preferred way to develop it. Its cost estimates are typically accurate to about 25%, and it is the minimum study needed to declare mineral reserves.
Preliminary economic assessment (PEA, scoping study): An early study of a mineral project's potential economics, which may use inferred resources. It cannot support a reserve estimate.
Price torqueIn Finance: How much more a producer's earnings, cash flow or share price move than the price of the commodity it sells. Because much of a miner's cost is fixed, a 10% rise in the metal price can lift its margin by far more than 10%, and a fall cuts the margin just as sharply. (DataDeep Report on Gold Price Torque)
Prohibited foreign entity (PFE, specified foreign entity, foreign-influenced entity)In Batteries: A US tax-law category created in 2025 covering specified foreign entities, such as companies controlled by China, and foreign-influenced entities tied to them. It bars or limits clean-energy credits, including for batteries.
Proven and probable reserves (proven reserve, probable reserve, proved reserve, 2P reserves): The two classes of mineral reserve: proven reserves come from measured resources, probable reserves from indicated resources, after mining, processing and economic factors are applied.
Pyrometallurgy (pyrometallurgical recycling, smelting)In Batteries: Recovering metals by smelting at high temperature. It handles mixed feed robustly and recovers nickel, cobalt and copper, but loses lithium and aluminum to slag and uses much energy.

Q

Qualified person (QP, competent person): An experienced, professionally registered geologist or engineer who must prepare or sign off on public resource and reserve disclosures. JORC uses the term competent person.

R

Rare earth elements (rare earths, REE, REEs, rare earth metals, lanthanides): The 15 lanthanides plus scandium and yttrium, 17 chemically similar metals. They are not especially rare in the crust but are seldom concentrated and hard to separate.
Rare earth ore minerals (bastnäsite, bastnaesite, monazite, xenotime, eudialyte, allanite): The main minerals mined for rare earths. Bastnäsite and monazite carry mostly light rare earths; xenotime carries heavy ones; eudialyte carries both with zirconium. Monazite is often radioactive from thorium.
Rare earth oxide (REO, TREO, total rare earth oxide, HREO, heavy rare earth oxide): The standard form in which rare earth content and output are measured and traded. TREO is total rare earth oxide; HREO is the heavy share.
Rare earth separation (separation and refining, rare earth refining, separated rare earths): Splitting a mixed rare earth solution into individual high-purity oxides, usually by solvent extraction across hundreds of mixer-settler stages. It is the step China most dominates.
Rare-earth-free magnet (iron nitride magnet, iron nitride): Magnet materials under development that avoid rare earths, such as iron nitride. None yet matches NdFeB at scale.
Reasonable country of origin inquiry (RCOI): The good-faith check a company must run under the US conflict minerals rule to learn where its 3TG came from.
Recovery rate (material recovery rate)In Batteries: The share of a given metal in recycling feed that is recovered in usable form. Recyclers often quote rates of 95% or more for nickel and cobalt; lithium rates are usually lower.
Recycled content (recycled content minimums)In Batteries: The share of a product's material that comes from recycling. EU rules require new industrial and EV batteries to contain set minimums of recycled cobalt, lithium, nickel and lead from August 2031. See the table
Recycling rates (end-of-life recycling rate, EOL recycling rate, recycling input rate, secondary supply): The end-of-life recycling rate is the share of metal in discarded products that is recovered. The recycling input rate is the share of supply that comes from scrap of any kind.
Refractory metals (refractory metal): Metals with very high melting points and hardness: chiefly tungsten, molybdenum, tantalum, niobium and rhenium.
Regolith simulant (lunar simulant, JSC-1A, highland simulant): Earth-made material engineered to mimic lunar or Martian soil, used to test excavation and processing equipment.
Regolith sintering (sintered regolith): Heating regolith until grains fuse, to make bricks, landing pads or printed structures without binders from Earth.
Remanence (remanent magnetization): The magnetic flux density a magnet keeps after the magnetizing field is removed, measured in tesla.
Remotely operated vehicle (ROV, work-class ROV)In Computing: An uncrewed underwater robot controlled from a ship through a tether, used for cable repair, inspection and seabed work.
Reserve-to-production ratio (R/P ratio, R/P, reserve life): Current reserves divided by annual production, giving years of output at today's rate. Reserves grow with exploration and prices, so it is not an exhaustion date.
Resource confidence categories (measured resource, indicated resource, inferred resource, measured and indicated, M&I): Mineral resources are classed by geological confidence: measured is highest, indicated next and inferred lowest. Only measured and indicated resources can be converted to reserves.
Resource nationalism: Government moves to take a larger share of mineral wealth, through higher royalties, state ownership, export bans or local processing rules.
Responsible Minerals Initiative (RMI, Responsible Minerals Assurance Process, RMAP, Conflict Minerals Reporting Template, CMRT): An industry body that audits smelters and refiners against responsible sourcing standards and publishes the Conflict Minerals Reporting Template.
Rhenium: A very rare metal recovered from molybdenum concentrates of porphyry copper ores, used in jet-engine superalloys and refinery catalysts.
Room-and-pillar mining (room and pillar): An underground method that mines ore in rooms and leaves pillars of rock to hold up the roof, suited to flat-lying deposits.
Rotary kiln-electric furnace (RKEF, nickel pig iron, NPI, ferronickel): A smelting route that dries and reduces nickel laterite in a kiln, then melts it in an electric furnace to make ferronickel or nickel pig iron.
Rotterdam in-warehouse price (Rotterdam price, in-warehouse Rotterdam): A European benchmark for minor metals and concentrates delivered into a Rotterdam warehouse, used for tungsten, antimony and others.
Rubble-pile asteroid (rubble pile): An asteroid made of loose rock held together by weak gravity, which makes anchoring and digging difficult.
Run-of-mine ore (ROM, ROM pad, run of mine): Ore as it comes from the mine, before crushing or sorting. The ROM pad is where it is stockpiled ahead of the plant.

S

S-K 1300 (Regulation S-K Subpart 1300, SK-1300, S-K-1300, technical report summary, TRS): The US Securities and Exchange Commission rule for disclosing mining properties, in force since 2021. It requires a qualified person's technical report summary for material properties.
Samarium: A light rare earth used mainly in samarium-cobalt magnets, typically recovered as a minor by-product of mixed rare earth processing.
Samarium-cobalt magnet (SmCo, SmCo5, SmCo₅, Sm2Co17, Sm₂Co₁₇, samarium cobalt): A rare earth magnet that keeps its strength at higher temperatures and resists corrosion and radiation better than NdFeB. It is used in defense, aerospace and high-heat motors.
Seabed mining moratorium (moratorium, precautionary pause): Calls by governments, scientists and companies for a pause on deep-sea mining until its environmental effects are better understood.
Seafloor massive sulfides (SMS, polymetallic sulphides, polymetallic sulfides, seafloor massive sulphides): Copper, zinc, gold and silver deposits built up around hydrothermal vents on mid-ocean ridges.
Section 45X (45X, advanced manufacturing production credit)In Batteries: The US advanced manufacturing production credit. For batteries it pays $35 per kWh of cells and $10 per kWh of modules made and sold in the US, phasing down from 2030 to zero after 2032.
Section 232 (Section 232 tariffs, 232 tariffs)In Industry: A US law, from the Trade Expansion Act of 1962, that lets the president restrict imports that threaten national security. Its steel and aluminum tariffs, first set in 2018, were raised to 50% in June 2025.
Section 301 (Section 301 tariffs, USTR)In Industry: A US trade law that lets the US Trade Representative act against unfair foreign trade practices, the basis for the tariffs placed on many Chinese goods from 2018.
Sediment plume (plume, discharge plume, midwater plume, turbidity current): A cloud of fine sediment stirred up by seabed mining or discharged from the ship, which can drift far and smother seafloor life.
Sintered and bonded magnets (sintered magnet, sintered NdFeB, bonded magnet, bonded NdFeB, hot-deformed magnet): Sintered magnets are pressed from powder and fused in a furnace, giving the highest strength. Bonded magnets mix powder with a binder for complex shapes at lower strength.
Sintering (debinding)In Industry: Bonding powder particles into a solid by heating below the melting point. Binder-jetted metal parts and ceramics are densified this way.
Skarn (skarn deposit, garnet skarn, contact metasomatic deposit): A rock formed where hot fluids from an intrusion react with limestone or similar rock. Skarns host many tungsten, copper and zinc deposits.
Smelter (smelting plant)In Industry: A plant that extracts metal from ore or concentrate by heating it in furnaces, often producing an intermediate such as matte or crude metal for refining.
Solvent extraction (SX)In Batteries: Separating dissolved metals by mixing a water solution with an organic liquid that selectively picks up one metal. It is used both in battery recycling and in rare earth refining.
Specific impulse (Isp)In Aerospace: A measure of rocket engine efficiency: thrust produced per unit of propellant used per second, given in seconds. Higher is better. Hydrogen engines reach ≈450 s in vacuum; kerosene and methane engines sit lower, ≈300–380 s.
Sphalerite (zinc blende): Zinc sulfide, the main zinc ore mineral. Indium, germanium and cadmium are recovered from it as by-products.
Split estate (mineral estate, mineral rights, surface rights): Land where the surface and the minerals beneath it are owned separately. The mineral estate can often be developed despite the surface owner.
Spodumene (spodumene concentrate, SC6)In Batteries: A hard-rock lithium mineral mined chiefly in Australia and refined, largely in China, into lithium chemicals. It is sold as concentrate, often around 6% lithium oxide.
Sponsoring state (sponsoring State, sponsorship): A country that backs a company's application to the International Seabed Authority and is responsible for making sure it complies.
Stabilization clause (stability agreement, fiscal stability agreement): A term in a mining agreement that protects the investor from later changes in tax or law for a set period.
Stibnite (Sb₂S₃, antimony trisulfide): Antimony sulfide (Sb₂S₃), the main antimony ore mineral, found mostly in hydrothermal veins.
Stope (stoping, stope design): An underground opening from which ore is extracted. Stope layout and pillar sizing set how much ore can be recovered safely.
Strip ratio (stripping ratio, waste-to-ore ratio): The tonnes of waste rock that must be removed for each tonne of ore in an open-pit mine. A higher ratio means higher mining cost.
Submerged arc furnace (submerged-arc furnace, carbothermic reduction)In Industry: An electric furnace whose electrodes are buried in the charge, used to make ferroalloys and silicon metal by carbothermic reduction, in which carbon strips oxygen from ore.
Superalloy (nickel superalloy, Inconel)In Industry: A nickel-, cobalt- or iron-based alloy that keeps its strength and resists oxidation at very high temperatures, used in turbines and reactors. Inconel is a common family.
Swarf (magnet swarf): Fine metal chips and sludge from cutting and grinding. In magnet making it is a major feed for recycling.

T

Tailings (tailings dam, tailings storage facility, TSF): The finely ground waste left after minerals are extracted, usually stored behind dams or as dry stacks. Old tailings can sometimes be reprocessed for metal.
Tantalum (Ta₂O₅, tantalum pentoxide): A rare, corrosion-resistant refractory metal. Its main use is capacitors; it is also used in superalloys, chip wiring barriers and medical implants. Ore is priced on Ta₂O₅ content.
Tantalum capacitor (tantalum capacitors, tantalum-polymer capacitor): A small capacitor that uses tantalum powder and a thin tantalum oxide layer to store a lot of charge in little space, valued in phones, cars and defense electronics.
Technology readiness level (TRL)In Aerospace: A 1–9 scale, developed at NASA, for how mature a technology is, from basic principles observed to proven in operation. Agencies and investors use it to judge development risk. See the table
The Area (international seabed area, areas beyond national jurisdiction): Under the Law of the Sea, the seabed beyond any country's national jurisdiction, whose minerals are managed by the International Seabed Authority.
Toll processing (toll treatment, toll refining, tolling): Processing another company's ore or concentrate for a fee, without taking ownership of the metal.
Treatment and refining charges (TC/RC, TC/RCs, treatment charge, refining charge, payability, payable metal): Fees a smelter deducts for processing concentrate, set per tonne and per unit of payable metal. They rise when concentrate is plentiful and fall when it is scarce.
Troy ounce (oz t, troy oz)In Industry: The unit for precious metals, equal to ≈31.1 g, slightly heavier than an ordinary ounce.
Tungsten (wolfram): A very dense, hard metal with the highest melting point of any metal, ≈3,422 °C. Most goes into cemented carbide tools; defense uses include armor-piercing rounds.
Tungsten heavy alloy (heavy alloy, WHA): A dense alloy of ≈90–97% tungsten with nickel and iron or copper, used for counterweights, radiation shielding and kinetic penetrators.
Tungsten ore minerals (scheelite, wolframite): Scheelite (calcium tungstate) and wolframite (iron-manganese tungstate), the two minerals from which almost all tungsten is mined.
Tungsten trioxide basis (WO₃, WO3, tungsten trioxide): Tungsten ore grades and concentrate prices are quoted in tungsten trioxide (WO₃) content, not metal. WO₃ is ≈79% tungsten by weight.
Two-year rule (two year rule): An UNCLOS provision letting a sponsoring state require the ISA to finish exploitation rules within two years. Nauru triggered it in 2021; the deadline passed in 2023 without rules.

U

UNCLOS (United Nations Convention on the Law of the Sea, Law of the Sea, Part XI, 1994 Implementation Agreement): The 1982 UN Convention on the Law of the Sea. Its Part XI, as changed by a 1994 agreement, governs mining in the Area. The US has not ratified it.
Underground mining (underground mine, deep-level mining): Mining through shafts, declines and tunnels to reach deeper or narrower ore bodies. It costs more per tonne than open-pit mining but disturbs less surface.
Units of productionIn Finance: Depreciation based on how much an asset is used, such as tonnes mined or hours operated, relative to its expected total output. It matches the expense to activity and is common in mining and energy.
Unpatented mining claimIn Finance: A claim on US federal land that gives the holder the right to explore for and extract certain minerals without owning the land itself. It must be kept in good standing with annual maintenance fees to the Bureau of Land Management.
Unreliable Entity List: China's list of foreign companies it deems harmful to its interests, which can be barred from trading with or investing in China.
Urban miningIn Batteries: Recovering metals from discarded products such as batteries and electronics instead of mining ore.
US Commercial Space Launch Competitiveness Act (CSLCA, SPACE Act of 2015, 51 U.S.C. 51303): A 2015 US law that lets US citizens own and sell resources they extract from asteroids and other celestial bodies (51 U.S.C. §51303).
USGS critical minerals list (List of Critical Minerals, critical minerals list, US critical minerals list): The US list of minerals judged essential and at supply risk, required by the Energy Act of 2020. The final 2025 list, released in November 2025, has 60 entries, adding copper, silver and uranium.
USGS Mineral Commodity Summaries (Mineral Commodity Summaries, USGS MCS, Minerals Yearbook): The US Geological Survey's annual report on production, reserves, prices, trade and import reliance for ≈90 minerals, published early each year.

V

Volatiles (lunar volatiles, volatile resources): Substances that vaporize easily, such as water, carbon dioxide, ammonia and hydrogen, which may be trapped in lunar polar soil or asteroids.
Volatilization roasting (roasting)In Industry: Heating a sulfide concentrate in air so the target metal leaves as an oxide vapor that is collected as fume. It is used to make crude antimony trioxide.

W

Wassenaar Arrangement (Wassenaar)In Aerospace: A multilateral export-control regime in which participating states agree on lists of conventional arms and dual-use goods to control, then apply them in national rules.
WTO DS431 (DS431, China – Rare Earths): The World Trade Organization case in which China's export duties and quotas on rare earths, tungsten and molybdenum were ruled inconsistent with its trade commitments in 2014.

Z

Zeolite (zeolites, molecular sieve)In Industry: A crystalline aluminosilicate mineral with a regular network of tiny pores, used as a catalyst, ion exchanger, adsorbent and molecular sieve.